Merge branch 'master' into unlock-minitest

430 files changed, 2533 insertions, 1818 deletions

diff --git a/activesupport/CHANGELOG.md b/activesupport/CHANGELOG.md
index 4c3eded38a..facd723bc5 100644
--- a/activesupport/CHANGELOG.md
+++ b/activesupport/CHANGELOG.md
@@ -1,8 +1,44 @@
+*   Add `freeze_time` helper which freezes time to `Time.now` in tests.
+
+    *Prathamesh Sonpatki*
+
+*   Default `ActiveSupport::MessageEncryptor` to use AES 256 GCM encryption.
+
+    On for new Rails 5.2 apps. Upgrading apps can find the config as a new
+    framework default.
+
+    *Assain Jaleel*
+
+*   Cache: `write_multi`
+
+        Rails.cache.write_multi foo: 'bar', baz: 'qux'
+
+    Plus faster fetch_multi with stores that implement `write_multi_entries`.
+    Keys that aren't found may be written to the cache store in one shot
+    instead of separate writes.
+
+    The default implementation simply calls `write_entry` for each entry.
+    Stores may override if they're capable of one-shot bulk writes, like
+    Redis `MSET`.
+
+    *Jeremy Daer*
+
+*   Add default option to module and class attribute accessors.
+
+        mattr_accessor :settings, default: {}
+
+    Works for `mattr_reader`, `mattr_writer`, `cattr_accessor`, `cattr_reader`,
+    and `cattr_writer` as well.
+
+    *Genadi Samokovarov*
+
 *   Add `Date#prev_occurring` and `Date#next_occurring` to return specified next/previous occurring day of week.
 
     *Shota Iguchi*
 
-*   Add default option to class_attribute. Before:
+*   Add default option to `class_attribute`.
+
+    Before:
 
         class_attribute :settings
         self.settings = {}
diff --git a/activesupport/Rakefile b/activesupport/Rakefile
index 2e1c50cc3d..8691a34035 100644
--- a/activesupport/Rakefile
+++ b/activesupport/Rakefile
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "rake/testtask"
 
 task default: :test
diff --git a/activesupport/activesupport.gemspec b/activesupport/activesupport.gemspec
index ed277c81ef..4470de7ec1 100644
--- a/activesupport/activesupport.gemspec
+++ b/activesupport/activesupport.gemspec
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 version = File.read(File.expand_path("../RAILS_VERSION", __dir__)).strip
 
 Gem::Specification.new do |s|
@@ -20,6 +21,11 @@ Gem::Specification.new do |s|
 
   s.rdoc_options.concat ["--encoding",  "UTF-8"]
 
+  s.metadata = {
+    "source_code_uri" => "https://github.com/rails/rails/tree/v#{version}/activesupport",
+    "changelog_uri"   => "https://github.com/rails/rails/blob/v#{version}/activesupport/CHANGELOG.md"
+  }
+
   s.add_dependency "i18n",       "~> 0.7"
   s.add_dependency "tzinfo",     "~> 1.1"
   s.add_dependency "minitest",   "~> 5.1"
diff --git a/activesupport/bin/generate_tables b/activesupport/bin/generate_tables
index 6f62593f14..18199b2171 100755
--- a/activesupport/bin/generate_tables
+++ b/activesupport/bin/generate_tables
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 begin
   $:.unshift(File.expand_path("../lib", __dir__))
diff --git a/activesupport/bin/test b/activesupport/bin/test
index a7beb14b27..c53377cc97 100755
--- a/activesupport/bin/test
+++ b/activesupport/bin/test
@@ -1,4 +1,5 @@
 #!/usr/bin/env ruby
+# frozen_string_literal: true
 
 COMPONENT_ROOT = File.expand_path("..", __dir__)
-require File.expand_path("../tools/test", COMPONENT_ROOT)
+require_relative "../../tools/test"
diff --git a/activesupport/lib/active_support.rb b/activesupport/lib/active_support.rb
index a667fbb54a..65e903aeb9 100644
--- a/activesupport/lib/active_support.rb
+++ b/activesupport/lib/active_support.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 #--
 # Copyright (c) 2005-2017 David Heinemeier Hansson
 #
@@ -22,11 +23,11 @@
 #++
 
 require "securerandom"
-require "active_support/dependencies/autoload"
-require "active_support/version"
-require "active_support/logger"
-require "active_support/lazy_load_hooks"
-require "active_support/core_ext/date_and_time/compatibility"
+require_relative "active_support/dependencies/autoload"
+require_relative "active_support/version"
+require_relative "active_support/logger"
+require_relative "active_support/lazy_load_hooks"
+require_relative "active_support/core_ext/date_and_time/compatibility"
 
 module ActiveSupport
   extend ActiveSupport::Autoload
diff --git a/activesupport/lib/active_support/all.rb b/activesupport/lib/active_support/all.rb
index 72a23075af..89f5d2b258 100644
--- a/activesupport/lib/active_support/all.rb
+++ b/activesupport/lib/active_support/all.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "active_support"
-require "active_support/time"
-require "active_support/core_ext"
+require_relative "time"
+require_relative "core_ext"
diff --git a/activesupport/lib/active_support/array_inquirer.rb b/activesupport/lib/active_support/array_inquirer.rb
index befa1746c6..6dad208e43 100644
--- a/activesupport/lib/active_support/array_inquirer.rb
+++ b/activesupport/lib/active_support/array_inquirer.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # Wrapping an array in an +ArrayInquirer+ gives a friendlier way to check
   # its string-like contents:
diff --git a/activesupport/lib/active_support/backtrace_cleaner.rb b/activesupport/lib/active_support/backtrace_cleaner.rb
index e47c90597f..1ffa2c05a2 100644
--- a/activesupport/lib/active_support/backtrace_cleaner.rb
+++ b/activesupport/lib/active_support/backtrace_cleaner.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # Backtraces often include many lines that are not relevant for the context
   # under review. This makes it hard to find the signal amongst the backtrace
diff --git a/activesupport/lib/active_support/benchmarkable.rb b/activesupport/lib/active_support/benchmarkable.rb
index 70493c8da7..a201b43fdc 100644
--- a/activesupport/lib/active_support/benchmarkable.rb
+++ b/activesupport/lib/active_support/benchmarkable.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/benchmark"
-require "active_support/core_ext/hash/keys"
+# frozen_string_literal: true
+require_relative "core_ext/benchmark"
+require_relative "core_ext/hash/keys"
 
 module ActiveSupport
   module Benchmarkable
diff --git a/activesupport/lib/active_support/builder.rb b/activesupport/lib/active_support/builder.rb
index 0f010c5d96..a7582a4f00 100644
--- a/activesupport/lib/active_support/builder.rb
+++ b/activesupport/lib/active_support/builder.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 begin
   require "builder"
 rescue LoadError => e
diff --git a/activesupport/lib/active_support/cache.rb b/activesupport/lib/active_support/cache.rb
index a1093a2e23..2ced73a0a6 100644
--- a/activesupport/lib/active_support/cache.rb
+++ b/activesupport/lib/active_support/cache.rb
@@ -1,11 +1,12 @@
+# frozen_string_literal: true
 require "zlib"
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/array/wrap"
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/numeric/bytes"
-require "active_support/core_ext/numeric/time"
-require "active_support/core_ext/object/to_param"
-require "active_support/core_ext/string/inflections"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/array/wrap"
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/numeric/bytes"
+require_relative "core_ext/numeric/time"
+require_relative "core_ext/object/to_param"
+require_relative "core_ext/string/inflections"
 
 module ActiveSupport
   # See ActiveSupport::Cache::Store for documentation.
@@ -75,7 +76,7 @@ module ActiveSupport
       #
       # The +key+ argument can also respond to +cache_key+ or +to_param+.
       def expand_cache_key(key, namespace = nil)
-        expanded_cache_key = namespace ? "#{namespace}/" : ""
+        expanded_cache_key = (namespace ? "#{namespace}/" : "").dup
 
         if prefix = ENV["RAILS_CACHE_ID"] || ENV["RAILS_APP_VERSION"]
           expanded_cache_key << "#{prefix}/"
@@ -99,7 +100,7 @@ module ActiveSupport
         # Obtains the specified cache store class, given the name of the +store+.
         # Raises an error when the store class cannot be found.
         def retrieve_store_class(store)
-          require "active_support/cache/#{store}"
+          require_relative "cache/#{store}"
         rescue LoadError => e
           raise "Could not find cache store adapter for #{store} (#{e})"
         else
@@ -373,6 +374,19 @@ module ActiveSupport
         results
       end
 
+      # Cache Storage API to write multiple values at once.
+      def write_multi(hash, options = nil)
+        options = merged_options(options)
+
+        instrument :write_multi, hash, options do |payload|
+          entries = hash.each_with_object({}) do |(name, value), memo|
+            memo[normalize_key(name, options)] = Entry.new(value, options.merge(version: normalize_version(name, options)))
+          end
+
+          write_multi_entries entries, options
+        end
+      end
+
       # Fetches data from the cache, using the given keys. If there is data in
       # the cache with the given keys, then that data is returned. Otherwise,
       # the supplied block is called for each key for which there was no data,
@@ -397,14 +411,15 @@ module ActiveSupport
 
         options = names.extract_options!
         options = merged_options(options)
-        results = read_multi(*names, options)
 
-        names.each_with_object({}) do |name, memo|
-          memo[name] = results.fetch(name) do
-            value = yield name
-            write(name, value, options)
-            value
+        read_multi(*names, options).tap do |results|
+          writes = {}
+
+          (names - results.keys).each do |name|
+            results[name] = writes[name] = yield(name)
           end
+
+          write_multi writes, options
         end
       end
 
@@ -485,7 +500,7 @@ module ActiveSupport
       # The options hash is passed to the underlying cache implementation.
       #
       # All implementations may not support this method.
-      def clear
+      def clear(options = nil)
         raise NotImplementedError.new("#{self.class.name} does not support clear")
       end
 
@@ -521,6 +536,14 @@ module ActiveSupport
           raise NotImplementedError.new
         end
 
+        # Writes multiple entries to the cache implementation. Subclasses MAY
+        # implement this method.
+        def write_multi_entries(hash, options)
+          hash.each do |key, entry|
+            write_entry key, entry, options
+          end
+        end
+
         # Deletes an entry from the cache implementation. Subclasses must
         # implement this method.
         def delete_entry(key, options)
diff --git a/activesupport/lib/active_support/cache/file_store.rb b/activesupport/lib/active_support/cache/file_store.rb
index d5c8585816..87182e0254 100644
--- a/activesupport/lib/active_support/cache/file_store.rb
+++ b/activesupport/lib/active_support/cache/file_store.rb
@@ -1,6 +1,7 @@
-require "active_support/core_ext/marshal"
-require "active_support/core_ext/file/atomic"
-require "active_support/core_ext/string/conversions"
+# frozen_string_literal: true
+require_relative "../core_ext/marshal"
+require_relative "../core_ext/file/atomic"
+require_relative "../core_ext/string/conversions"
 require "uri/common"
 
 module ActiveSupport
@@ -27,7 +28,7 @@ module ActiveSupport
       # Deletes all items from the cache. In this case it deletes all the entries in the specified
       # file store directory except for .keep or .gitkeep. Be careful which directory is specified in your
       # config file when using +FileStore+ because everything in that directory will be deleted.
-      def clear
+      def clear(options = nil)
         root_dirs = exclude_from(cache_path, EXCLUDED_DIRS + GITKEEP_FILES)
         FileUtils.rm_r(root_dirs.collect { |f| File.join(cache_path, f) })
       rescue Errno::ENOENT
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 06fa9f67ad..de05dde8d4 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 begin
   require "dalli"
 rescue LoadError => e
@@ -6,8 +7,8 @@ rescue LoadError => e
 end
 
 require "digest/md5"
-require "active_support/core_ext/marshal"
-require "active_support/core_ext/array/extract_options"
+require_relative "../core_ext/marshal"
+require_relative "../core_ext/array/extract_options"
 
 module ActiveSupport
   module Cache
diff --git a/activesupport/lib/active_support/cache/memory_store.rb b/activesupport/lib/active_support/cache/memory_store.rb
index 56fe1457d0..e1fee72595 100644
--- a/activesupport/lib/active_support/cache/memory_store.rb
+++ b/activesupport/lib/active_support/cache/memory_store.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "monitor"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/cache/null_store.rb b/activesupport/lib/active_support/cache/null_store.rb
index 550659fc56..10ffbb84ea 100644
--- a/activesupport/lib/active_support/cache/null_store.rb
+++ b/activesupport/lib/active_support/cache/null_store.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Cache
     # A cache store implementation which doesn't actually store anything. Useful in
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache.rb b/activesupport/lib/active_support/cache/strategy/local_cache.rb
index 91875a56f5..f3b65bcdef 100644
--- a/activesupport/lib/active_support/cache/strategy/local_cache.rb
+++ b/activesupport/lib/active_support/cache/strategy/local_cache.rb
@@ -1,6 +1,7 @@
-require "active_support/core_ext/object/duplicable"
-require "active_support/core_ext/string/inflections"
-require "active_support/per_thread_registry"
+# frozen_string_literal: true
+require_relative "../../core_ext/object/duplicable"
+require_relative "../../core_ext/string/inflections"
+require_relative "../../per_thread_registry"
 
 module ActiveSupport
   module Cache
@@ -44,7 +45,7 @@ module ActiveSupport
             yield
           end
 
-          def clear
+          def clear(options = nil)
             @data.clear
           end
 
@@ -79,15 +80,15 @@ module ActiveSupport
             local_cache_key)
         end
 
-        def clear # :nodoc:
+        def clear(options = nil) # :nodoc:
           return super unless cache = local_cache
-          cache.clear
+          cache.clear(options)
           super
         end
 
         def cleanup(options = nil) # :nodoc:
           return super unless cache = local_cache
-          cache.clear(options)
+          cache.clear
           super
         end
 
diff --git a/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb b/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb
index 4c3679e4bf..a53e268a92 100644
--- a/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb
+++ b/activesupport/lib/active_support/cache/strategy/local_cache_middleware.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "rack/body_proxy"
 require "rack/utils"
 
diff --git a/activesupport/lib/active_support/callbacks.rb b/activesupport/lib/active_support/callbacks.rb
index ddfa91a342..5cf8dbea90 100644
--- a/activesupport/lib/active_support/callbacks.rb
+++ b/activesupport/lib/active_support/callbacks.rb
@@ -1,11 +1,12 @@
-require "active_support/concern"
-require "active_support/descendants_tracker"
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/class/attribute"
-require "active_support/core_ext/kernel/reporting"
-require "active_support/core_ext/kernel/singleton_class"
-require "active_support/core_ext/string/filters"
-require "active_support/deprecation"
+# frozen_string_literal: true
+require_relative "concern"
+require_relative "descendants_tracker"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/class/attribute"
+require_relative "core_ext/kernel/reporting"
+require_relative "core_ext/kernel/singleton_class"
+require_relative "core_ext/string/filters"
+require_relative "deprecation"
 require "thread"
 
 module ActiveSupport
@@ -596,7 +597,7 @@ module ActiveSupport
             Proc.new do |target, result_lambda|
               terminate = true
               catch(:abort) do
-                result_lambda.call if result_lambda.is_a?(Proc)
+                result_lambda.call
                 terminate = false
               end
               terminate
@@ -662,8 +663,10 @@ module ActiveSupport
 
           if options[:if].is_a?(String) || options[:unless].is_a?(String)
             ActiveSupport::Deprecation.warn(<<-MSG.squish)
-              Passing string to :if and :unless conditional options is deprecated
-              and will be removed in Rails 5.2 without replacement.
+              Passing string to be evaluated in :if and :unless conditional
+              options is deprecated and will be removed in Rails 5.2 without
+              replacement. Pass a symbol for an instance method, or a lambda,
+              proc or block, instead.
             MSG
           end
 
diff --git a/activesupport/lib/active_support/concern.rb b/activesupport/lib/active_support/concern.rb
index 0403eb70ca..f1dcda7dfa 100644
--- a/activesupport/lib/active_support/concern.rb
+++ b/activesupport/lib/active_support/concern.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # A typical module looks like this:
   #
diff --git a/activesupport/lib/active_support/concurrency/share_lock.rb b/activesupport/lib/active_support/concurrency/share_lock.rb
index 4318523b07..060b16f2d6 100644
--- a/activesupport/lib/active_support/concurrency/share_lock.rb
+++ b/activesupport/lib/active_support/concurrency/share_lock.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "thread"
 require "monitor"
 
diff --git a/activesupport/lib/active_support/configurable.rb b/activesupport/lib/active_support/configurable.rb
index f72a893bcc..490925f37e 100644
--- a/activesupport/lib/active_support/configurable.rb
+++ b/activesupport/lib/active_support/configurable.rb
@@ -1,7 +1,8 @@
-require "active_support/concern"
-require "active_support/ordered_options"
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "concern"
+require_relative "ordered_options"
+require_relative "core_ext/array/extract_options"
+require_relative "core_ext/regexp"
 
 module ActiveSupport
   # Configurable provides a <tt>config</tt> method to store and retrieve
diff --git a/activesupport/lib/active_support/core_ext.rb b/activesupport/lib/active_support/core_ext.rb
index 42e0acf66a..784cdc4a78 100644
--- a/activesupport/lib/active_support/core_ext.rb
+++ b/activesupport/lib/active_support/core_ext.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 Dir.glob(File.expand_path("core_ext/*.rb", __dir__)).each do |path|
   require path
 end
diff --git a/activesupport/lib/active_support/core_ext/array.rb b/activesupport/lib/active_support/core_ext/array.rb
index e908386a1c..c2876785dc 100644
--- a/activesupport/lib/active_support/core_ext/array.rb
+++ b/activesupport/lib/active_support/core_ext/array.rb
@@ -1,7 +1,8 @@
-require "active_support/core_ext/array/wrap"
-require "active_support/core_ext/array/access"
-require "active_support/core_ext/array/conversions"
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/array/grouping"
-require "active_support/core_ext/array/prepend_and_append"
-require "active_support/core_ext/array/inquiry"
+# frozen_string_literal: true
+require_relative "array/wrap"
+require_relative "array/access"
+require_relative "array/conversions"
+require_relative "array/extract_options"
+require_relative "array/grouping"
+require_relative "array/prepend_and_append"
+require_relative "array/inquiry"
diff --git a/activesupport/lib/active_support/core_ext/array/access.rb b/activesupport/lib/active_support/core_ext/array/access.rb
index fca33c9d69..b6e576ad29 100644
--- a/activesupport/lib/active_support/core_ext/array/access.rb
+++ b/activesupport/lib/active_support/core_ext/array/access.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Array
   # Returns the tail of the array from +position+.
   #
diff --git a/activesupport/lib/active_support/core_ext/array/conversions.rb b/activesupport/lib/active_support/core_ext/array/conversions.rb
index cac15e1100..eeafde78a4 100644
--- a/activesupport/lib/active_support/core_ext/array/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/array/conversions.rb
@@ -1,8 +1,9 @@
-require "active_support/xml_mini"
-require "active_support/core_ext/hash/keys"
-require "active_support/core_ext/string/inflections"
-require "active_support/core_ext/object/to_param"
-require "active_support/core_ext/object/to_query"
+# frozen_string_literal: true
+require_relative "../../xml_mini"
+require_relative "../hash/keys"
+require_relative "../string/inflections"
+require_relative "../object/to_param"
+require_relative "../object/to_query"
 
 class Array
   # Converts the array to a comma-separated sentence where the last element is
@@ -179,7 +180,7 @@ class Array
   #   </messages>
   #
   def to_xml(options = {})
-    require "active_support/builder" unless defined?(Builder)
+    require_relative "../../builder" unless defined?(Builder)
 
     options = options.dup
     options[:indent]  ||= 2
diff --git a/activesupport/lib/active_support/core_ext/array/extract_options.rb b/activesupport/lib/active_support/core_ext/array/extract_options.rb
index 9008a0df2a..8204d42caf 100644
--- a/activesupport/lib/active_support/core_ext/array/extract_options.rb
+++ b/activesupport/lib/active_support/core_ext/array/extract_options.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # By default, only instances of Hash itself are extractable.
   # Subclasses of Hash may implement this method and return
diff --git a/activesupport/lib/active_support/core_ext/array/grouping.rb b/activesupport/lib/active_support/core_ext/array/grouping.rb
index 0d798e5c4e..706c576691 100644
--- a/activesupport/lib/active_support/core_ext/array/grouping.rb
+++ b/activesupport/lib/active_support/core_ext/array/grouping.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Array
   # Splits or iterates over the array in groups of size +number+,
   # padding any remaining slots with +fill_with+ unless it is +false+.
diff --git a/activesupport/lib/active_support/core_ext/array/inquiry.rb b/activesupport/lib/active_support/core_ext/array/inquiry.rb
index 66fa5fcd0c..b8a1bbdbc7 100644
--- a/activesupport/lib/active_support/core_ext/array/inquiry.rb
+++ b/activesupport/lib/active_support/core_ext/array/inquiry.rb
@@ -1,4 +1,5 @@
-require "active_support/array_inquirer"
+# frozen_string_literal: true
+require_relative "../../array_inquirer"
 
 class Array
   # Wraps the array in an +ArrayInquirer+ object, which gives a friendlier way
diff --git a/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb b/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
index 88a34128c9..2dd1547765 100644
--- a/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
+++ b/activesupport/lib/active_support/core_ext/array/prepend_and_append.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Array
   # The human way of thinking about adding stuff to the end of a list is with append.
   alias_method :append,  :push unless [].respond_to?(:append)
diff --git a/activesupport/lib/active_support/core_ext/array/wrap.rb b/activesupport/lib/active_support/core_ext/array/wrap.rb
index b611d34c27..adb25718e4 100644
--- a/activesupport/lib/active_support/core_ext/array/wrap.rb
+++ b/activesupport/lib/active_support/core_ext/array/wrap.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Array
   # Wraps its argument in an array unless it is already an array (or array-like).
   #
diff --git a/activesupport/lib/active_support/core_ext/benchmark.rb b/activesupport/lib/active_support/core_ext/benchmark.rb
index 2300953860..2db6e5f1c5 100644
--- a/activesupport/lib/active_support/core_ext/benchmark.rb
+++ b/activesupport/lib/active_support/core_ext/benchmark.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "benchmark"
 
 class << Benchmark
diff --git a/activesupport/lib/active_support/core_ext/big_decimal.rb b/activesupport/lib/active_support/core_ext/big_decimal.rb
index 7b4f87f10e..fd860f6fbd 100644
--- a/activesupport/lib/active_support/core_ext/big_decimal.rb
+++ b/activesupport/lib/active_support/core_ext/big_decimal.rb
@@ -1 +1,2 @@
-require "active_support/core_ext/big_decimal/conversions"
+# frozen_string_literal: true
+require_relative "big_decimal/conversions"
diff --git a/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb b/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb
index decd4e1699..1729f00530 100644
--- a/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/big_decimal/conversions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "bigdecimal"
 require "bigdecimal/util"
 
diff --git a/activesupport/lib/active_support/core_ext/class.rb b/activesupport/lib/active_support/core_ext/class.rb
index 6a19e862d0..882102831f 100644
--- a/activesupport/lib/active_support/core_ext/class.rb
+++ b/activesupport/lib/active_support/core_ext/class.rb
@@ -1,2 +1,3 @@
-require "active_support/core_ext/class/attribute"
-require "active_support/core_ext/class/subclasses"
+# frozen_string_literal: true
+require_relative "class/attribute"
+require_relative "class/subclasses"
diff --git a/activesupport/lib/active_support/core_ext/class/attribute.rb b/activesupport/lib/active_support/core_ext/class/attribute.rb
index 8caddcd5c3..a6da65e96d 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute.rb
@@ -1,6 +1,7 @@
-require "active_support/core_ext/kernel/singleton_class"
-require "active_support/core_ext/module/remove_method"
-require "active_support/core_ext/array/extract_options"
+# frozen_string_literal: true
+require_relative "../kernel/singleton_class"
+require_relative "../module/remove_method"
+require_relative "../array/extract_options"
 
 class Class
   # Declare a class-level attribute whose value is inheritable by subclasses.
diff --git a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
index 0f767925ed..0345478c59 100644
--- a/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
+++ b/activesupport/lib/active_support/core_ext/class/attribute_accessors.rb
@@ -1,4 +1,5 @@
+# frozen_string_literal: true
 # cattr_* became mattr_* aliases in 7dfbd91b0780fbd6a1dd9bfbc176e10894871d2d,
 # but we keep this around for libraries that directly require it knowing they
 # want cattr_*. No need to deprecate.
-require "active_support/core_ext/module/attribute_accessors"
+require_relative "../module/attribute_accessors"
diff --git a/activesupport/lib/active_support/core_ext/class/subclasses.rb b/activesupport/lib/active_support/core_ext/class/subclasses.rb
index 62397d9508..ce7b422cfb 100644
--- a/activesupport/lib/active_support/core_ext/class/subclasses.rb
+++ b/activesupport/lib/active_support/core_ext/class/subclasses.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/module/anonymous"
-require "active_support/core_ext/module/reachable"
+# frozen_string_literal: true
+require_relative "../module/anonymous"
+require_relative "../module/reachable"
 
 class Class
   begin
diff --git a/activesupport/lib/active_support/core_ext/date.rb b/activesupport/lib/active_support/core_ext/date.rb
index 4f66804da2..88bae739b6 100644
--- a/activesupport/lib/active_support/core_ext/date.rb
+++ b/activesupport/lib/active_support/core_ext/date.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/date/acts_like"
-require "active_support/core_ext/date/blank"
-require "active_support/core_ext/date/calculations"
-require "active_support/core_ext/date/conversions"
-require "active_support/core_ext/date/zones"
+# frozen_string_literal: true
+require_relative "date/acts_like"
+require_relative "date/blank"
+require_relative "date/calculations"
+require_relative "date/conversions"
+require_relative "date/zones"
diff --git a/activesupport/lib/active_support/core_ext/date/acts_like.rb b/activesupport/lib/active_support/core_ext/date/acts_like.rb
index 46fe99ad47..c8ab7b5241 100644
--- a/activesupport/lib/active_support/core_ext/date/acts_like.rb
+++ b/activesupport/lib/active_support/core_ext/date/acts_like.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/acts_like"
+# frozen_string_literal: true
+require_relative "../object/acts_like"
 
 class Date
   # Duck-types as a Date-like class. See Object#acts_like?.
diff --git a/activesupport/lib/active_support/core_ext/date/blank.rb b/activesupport/lib/active_support/core_ext/date/blank.rb
index edd2847126..a28e726902 100644
--- a/activesupport/lib/active_support/core_ext/date/blank.rb
+++ b/activesupport/lib/active_support/core_ext/date/blank.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "date"
 
 class Date #:nodoc:
diff --git a/activesupport/lib/active_support/core_ext/date/calculations.rb b/activesupport/lib/active_support/core_ext/date/calculations.rb
index d6f60cac04..d0ac71210a 100644
--- a/activesupport/lib/active_support/core_ext/date/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date/calculations.rb
@@ -1,9 +1,10 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/duration"
-require "active_support/core_ext/object/acts_like"
-require "active_support/core_ext/date/zones"
-require "active_support/core_ext/time/zones"
-require "active_support/core_ext/date_and_time/calculations"
+require_relative "../../duration"
+require_relative "../object/acts_like"
+require_relative "zones"
+require_relative "../time/zones"
+require_relative "../date_and_time/calculations"
 
 class Date
   include DateAndTime::Calculations
diff --git a/activesupport/lib/active_support/core_ext/date/conversions.rb b/activesupport/lib/active_support/core_ext/date/conversions.rb
index 0f59c754fe..6c493dc2c8 100644
--- a/activesupport/lib/active_support/core_ext/date/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/date/conversions.rb
@@ -1,7 +1,8 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/inflector/methods"
-require "active_support/core_ext/date/zones"
-require "active_support/core_ext/module/remove_method"
+require_relative "../../inflector/methods"
+require_relative "zones"
+require_relative "../module/remove_method"
 
 class Date
   DATE_FORMATS = {
diff --git a/activesupport/lib/active_support/core_ext/date/zones.rb b/activesupport/lib/active_support/core_ext/date/zones.rb
index da23fe4892..f9bb6f733b 100644
--- a/activesupport/lib/active_support/core_ext/date/zones.rb
+++ b/activesupport/lib/active_support/core_ext/date/zones.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/core_ext/date_and_time/zones"
+require_relative "../date_and_time/zones"
 
 class Date
   include DateAndTime::Zones
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
index e2e1d3e359..4e93851259 100644
--- a/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_and_time/calculations.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/try"
+# frozen_string_literal: true
+require_relative "../object/try"
 
 module DateAndTime
   module Calculations
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb b/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb
index ab80392460..ffb1cbd6e5 100644
--- a/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb
+++ b/activesupport/lib/active_support/core_ext/date_and_time/compatibility.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/module/attribute_accessors"
+# frozen_string_literal: true
+require_relative "../module/attribute_accessors"
 
 module DateAndTime
   module Compatibility
@@ -9,6 +10,6 @@ module DateAndTime
     # of the receiver. For backwards compatibility we're overriding
     # this behavior, but new apps will have an initializer that sets
     # this to true, because the new behavior is preferred.
-    mattr_accessor(:preserve_timezone, instance_writer: false) { false }
+    mattr_accessor :preserve_timezone, instance_writer: false, default: false
   end
 end
diff --git a/activesupport/lib/active_support/core_ext/date_and_time/zones.rb b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
index edd724f1d0..4cc94d4ece 100644
--- a/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
+++ b/activesupport/lib/active_support/core_ext/date_and_time/zones.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module DateAndTime
   module Zones
     # Returns the simultaneous time in <tt>Time.zone</tt> if a zone is given or
diff --git a/activesupport/lib/active_support/core_ext/date_time.rb b/activesupport/lib/active_support/core_ext/date_time.rb
index 6fd498f864..fba37a5169 100644
--- a/activesupport/lib/active_support/core_ext/date_time.rb
+++ b/activesupport/lib/active_support/core_ext/date_time.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/date_time/acts_like"
-require "active_support/core_ext/date_time/blank"
-require "active_support/core_ext/date_time/calculations"
-require "active_support/core_ext/date_time/compatibility"
-require "active_support/core_ext/date_time/conversions"
+# frozen_string_literal: true
+require_relative "date_time/acts_like"
+require_relative "date_time/blank"
+require_relative "date_time/calculations"
+require_relative "date_time/compatibility"
+require_relative "date_time/conversions"
diff --git a/activesupport/lib/active_support/core_ext/date_time/acts_like.rb b/activesupport/lib/active_support/core_ext/date_time/acts_like.rb
index 6f50f55a53..74a2758830 100644
--- a/activesupport/lib/active_support/core_ext/date_time/acts_like.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/acts_like.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/core_ext/object/acts_like"
+require_relative "../object/acts_like"
 
 class DateTime
   # Duck-types as a Date-like class. See Object#acts_like?.
diff --git a/activesupport/lib/active_support/core_ext/date_time/blank.rb b/activesupport/lib/active_support/core_ext/date_time/blank.rb
index b475fd926d..874c7554a3 100644
--- a/activesupport/lib/active_support/core_ext/date_time/blank.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/blank.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "date"
 
 class DateTime #:nodoc:
diff --git a/activesupport/lib/active_support/core_ext/date_time/calculations.rb b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
index 7a9eb8c266..91289175ed 100644
--- a/activesupport/lib/active_support/core_ext/date_time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/calculations.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "date"
 
 class DateTime
diff --git a/activesupport/lib/active_support/core_ext/date_time/compatibility.rb b/activesupport/lib/active_support/core_ext/date_time/compatibility.rb
index 870391aeaa..e2bb02d855 100644
--- a/activesupport/lib/active_support/core_ext/date_time/compatibility.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/compatibility.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/date_and_time/compatibility"
-require "active_support/core_ext/module/remove_method"
+# frozen_string_literal: true
+require_relative "../date_and_time/compatibility"
+require_relative "../module/remove_method"
 
 class DateTime
   include DateAndTime::Compatibility
diff --git a/activesupport/lib/active_support/core_ext/date_time/conversions.rb b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
index d9b3743858..2a35f9dbfb 100644
--- a/activesupport/lib/active_support/core_ext/date_time/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/date_time/conversions.rb
@@ -1,8 +1,9 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/inflector/methods"
-require "active_support/core_ext/time/conversions"
-require "active_support/core_ext/date_time/calculations"
-require "active_support/values/time_zone"
+require_relative "../../inflector/methods"
+require_relative "../time/conversions"
+require_relative "calculations"
+require_relative "../../values/time_zone"
 
 class DateTime
   # Convert to a formatted string. See Time::DATE_FORMATS for predefined formats.
diff --git a/activesupport/lib/active_support/core_ext/digest/uuid.rb b/activesupport/lib/active_support/core_ext/digest/uuid.rb
index e6d60e3267..26a300feb6 100644
--- a/activesupport/lib/active_support/core_ext/digest/uuid.rb
+++ b/activesupport/lib/active_support/core_ext/digest/uuid.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "securerandom"
 
 module Digest
diff --git a/activesupport/lib/active_support/core_ext/enumerable.rb b/activesupport/lib/active_support/core_ext/enumerable.rb
index 3a4ae6cb8b..a744b78e1c 100644
--- a/activesupport/lib/active_support/core_ext/enumerable.rb
+++ b/activesupport/lib/active_support/core_ext/enumerable.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Enumerable
   # Enumerable#sum was added in Ruby 2.4, but it only works with Numeric elements
   # when we omit an identity.
diff --git a/activesupport/lib/active_support/core_ext/file.rb b/activesupport/lib/active_support/core_ext/file.rb
index 6d99bad2af..9de5fbb63c 100644
--- a/activesupport/lib/active_support/core_ext/file.rb
+++ b/activesupport/lib/active_support/core_ext/file.rb
@@ -1 +1,2 @@
-require "active_support/core_ext/file/atomic"
+# frozen_string_literal: true
+require_relative "file/atomic"
diff --git a/activesupport/lib/active_support/core_ext/file/atomic.rb b/activesupport/lib/active_support/core_ext/file/atomic.rb
index 8d6c0d3685..5b30e93357 100644
--- a/activesupport/lib/active_support/core_ext/file/atomic.rb
+++ b/activesupport/lib/active_support/core_ext/file/atomic.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "fileutils"
 
 class File
diff --git a/activesupport/lib/active_support/core_ext/hash.rb b/activesupport/lib/active_support/core_ext/hash.rb
index c819307e8a..24b6adeb5f 100644
--- a/activesupport/lib/active_support/core_ext/hash.rb
+++ b/activesupport/lib/active_support/core_ext/hash.rb
@@ -1,9 +1,10 @@
-require "active_support/core_ext/hash/compact"
-require "active_support/core_ext/hash/conversions"
-require "active_support/core_ext/hash/deep_merge"
-require "active_support/core_ext/hash/except"
-require "active_support/core_ext/hash/indifferent_access"
-require "active_support/core_ext/hash/keys"
-require "active_support/core_ext/hash/reverse_merge"
-require "active_support/core_ext/hash/slice"
-require "active_support/core_ext/hash/transform_values"
+# frozen_string_literal: true
+require_relative "hash/compact"
+require_relative "hash/conversions"
+require_relative "hash/deep_merge"
+require_relative "hash/except"
+require_relative "hash/indifferent_access"
+require_relative "hash/keys"
+require_relative "hash/reverse_merge"
+require_relative "hash/slice"
+require_relative "hash/transform_values"
diff --git a/activesupport/lib/active_support/core_ext/hash/compact.rb b/activesupport/lib/active_support/core_ext/hash/compact.rb
index e357284be0..ddccbe7d16 100644
--- a/activesupport/lib/active_support/core_ext/hash/compact.rb
+++ b/activesupport/lib/active_support/core_ext/hash/compact.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   unless Hash.instance_methods(false).include?(:compact)
     # Returns a hash with non +nil+ values.
diff --git a/activesupport/lib/active_support/core_ext/hash/conversions.rb b/activesupport/lib/active_support/core_ext/hash/conversions.rb
index 2a58a7f1ca..193004608a 100644
--- a/activesupport/lib/active_support/core_ext/hash/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/hash/conversions.rb
@@ -1,11 +1,12 @@
-require "active_support/xml_mini"
-require "active_support/time"
-require "active_support/core_ext/object/blank"
-require "active_support/core_ext/object/to_param"
-require "active_support/core_ext/object/to_query"
-require "active_support/core_ext/array/wrap"
-require "active_support/core_ext/hash/reverse_merge"
-require "active_support/core_ext/string/inflections"
+# frozen_string_literal: true
+require_relative "../../xml_mini"
+require_relative "../../time"
+require_relative "../object/blank"
+require_relative "../object/to_param"
+require_relative "../object/to_query"
+require_relative "../array/wrap"
+require_relative "reverse_merge"
+require_relative "../string/inflections"
 
 class Hash
   # Returns a string containing an XML representation of its receiver:
@@ -71,7 +72,7 @@ class Hash
   # configure your own builder with the <tt>:builder</tt> option. The method also accepts
   # options like <tt>:dasherize</tt> and friends, they are forwarded to the builder.
   def to_xml(options = {})
-    require "active_support/builder" unless defined?(Builder)
+    require_relative "../../builder" unless defined?(Builder)
 
     options = options.dup
     options[:indent]  ||= 2
diff --git a/activesupport/lib/active_support/core_ext/hash/deep_merge.rb b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
index 9c9faf67ea..1c6627a597 100644
--- a/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
+++ b/activesupport/lib/active_support/core_ext/hash/deep_merge.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Returns a new hash with +self+ and +other_hash+ merged recursively.
   #
diff --git a/activesupport/lib/active_support/core_ext/hash/except.rb b/activesupport/lib/active_support/core_ext/hash/except.rb
index 2f6d38c1f6..e31c7c61e4 100644
--- a/activesupport/lib/active_support/core_ext/hash/except.rb
+++ b/activesupport/lib/active_support/core_ext/hash/except.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Returns a hash that includes everything except given keys.
   #   hash = { a: true, b: false, c: nil }
diff --git a/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
index 3e1ccecb6c..7727f0751e 100644
--- a/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
+++ b/activesupport/lib/active_support/core_ext/hash/indifferent_access.rb
@@ -1,4 +1,5 @@
-require "active_support/hash_with_indifferent_access"
+# frozen_string_literal: true
+require_relative "../../hash_with_indifferent_access"
 
 class Hash
   # Returns an <tt>ActiveSupport::HashWithIndifferentAccess</tt> out of its receiver:
diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index b7089357a8..b38ea9ba50 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Returns a new hash with all keys converted using the +block+ operation.
   #
diff --git a/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb b/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb
index 061c959442..2055d06385 100644
--- a/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb
+++ b/activesupport/lib/active_support/core_ext/hash/reverse_merge.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Merges the caller into +other_hash+. For example,
   #
diff --git a/activesupport/lib/active_support/core_ext/hash/slice.rb b/activesupport/lib/active_support/core_ext/hash/slice.rb
index 161b00dfb3..bd370931e4 100644
--- a/activesupport/lib/active_support/core_ext/hash/slice.rb
+++ b/activesupport/lib/active_support/core_ext/hash/slice.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Slices a hash to include only the given keys. Returns a hash containing
   # the given keys.
diff --git a/activesupport/lib/active_support/core_ext/hash/transform_values.rb b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
index 2f693bff0c..b6e2734193 100644
--- a/activesupport/lib/active_support/core_ext/hash/transform_values.rb
+++ b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Hash
   # Returns a new hash with the results of running +block+ once for every value.
   # The keys are unchanged.
diff --git a/activesupport/lib/active_support/core_ext/integer.rb b/activesupport/lib/active_support/core_ext/integer.rb
index 8f0c55f9d3..2042b5d311 100644
--- a/activesupport/lib/active_support/core_ext/integer.rb
+++ b/activesupport/lib/active_support/core_ext/integer.rb
@@ -1,3 +1,4 @@
-require "active_support/core_ext/integer/multiple"
-require "active_support/core_ext/integer/inflections"
-require "active_support/core_ext/integer/time"
+# frozen_string_literal: true
+require_relative "integer/multiple"
+require_relative "integer/inflections"
+require_relative "integer/time"
diff --git a/activesupport/lib/active_support/core_ext/integer/inflections.rb b/activesupport/lib/active_support/core_ext/integer/inflections.rb
index bc21b65533..de756446ba 100644
--- a/activesupport/lib/active_support/core_ext/integer/inflections.rb
+++ b/activesupport/lib/active_support/core_ext/integer/inflections.rb
@@ -1,4 +1,5 @@
-require "active_support/inflector"
+# frozen_string_literal: true
+require_relative "../../inflector"
 
 class Integer
   # Ordinalize turns a number into an ordinal string used to denote the
diff --git a/activesupport/lib/active_support/core_ext/integer/multiple.rb b/activesupport/lib/active_support/core_ext/integer/multiple.rb
index c668c7c2eb..2e4d78e66c 100644
--- a/activesupport/lib/active_support/core_ext/integer/multiple.rb
+++ b/activesupport/lib/active_support/core_ext/integer/multiple.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Integer
   # Check whether the integer is evenly divisible by the argument.
   #
diff --git a/activesupport/lib/active_support/core_ext/integer/time.rb b/activesupport/lib/active_support/core_ext/integer/time.rb
index 74baae3639..583ef456f3 100644
--- a/activesupport/lib/active_support/core_ext/integer/time.rb
+++ b/activesupport/lib/active_support/core_ext/integer/time.rb
@@ -1,5 +1,6 @@
-require "active_support/duration"
-require "active_support/core_ext/numeric/time"
+# frozen_string_literal: true
+require_relative "../../duration"
+require_relative "../numeric/time"
 
 class Integer
   # Enables the use of time calculations and declarations, like <tt>45.minutes +
diff --git a/activesupport/lib/active_support/core_ext/kernel.rb b/activesupport/lib/active_support/core_ext/kernel.rb
index 3d41ff7876..9ac0ba3749 100644
--- a/activesupport/lib/active_support/core_ext/kernel.rb
+++ b/activesupport/lib/active_support/core_ext/kernel.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/kernel/agnostics"
-require "active_support/core_ext/kernel/concern"
-require "active_support/core_ext/kernel/reporting"
-require "active_support/core_ext/kernel/singleton_class"
+# frozen_string_literal: true
+require_relative "kernel/agnostics"
+require_relative "kernel/concern"
+require_relative "kernel/reporting"
+require_relative "kernel/singleton_class"
diff --git a/activesupport/lib/active_support/core_ext/kernel/agnostics.rb b/activesupport/lib/active_support/core_ext/kernel/agnostics.rb
index 64837d87aa..84a48979c4 100644
--- a/activesupport/lib/active_support/core_ext/kernel/agnostics.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/agnostics.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Object
   # Makes backticks behave (somewhat more) similarly on all platforms.
   # On win32 `nonexistent_command` raises Errno::ENOENT; on Unix, the
diff --git a/activesupport/lib/active_support/core_ext/kernel/concern.rb b/activesupport/lib/active_support/core_ext/kernel/concern.rb
index 307a7f7a63..e6df8aa46e 100644
--- a/activesupport/lib/active_support/core_ext/kernel/concern.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/concern.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/module/concerning"
+# frozen_string_literal: true
+require_relative "../module/concerning"
 
 module Kernel
   module_function
diff --git a/activesupport/lib/active_support/core_ext/kernel/reporting.rb b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
index c02618d5f3..822efb5aae 100644
--- a/activesupport/lib/active_support/core_ext/kernel/reporting.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/reporting.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Kernel
   module_function
 
diff --git a/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb b/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb
index 9bbf1bbd73..5f9c008f6e 100644
--- a/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb
+++ b/activesupport/lib/active_support/core_ext/kernel/singleton_class.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module Kernel
   # class_eval on an object acts like singleton_class.class_eval.
   def class_eval(*args, &block)
diff --git a/activesupport/lib/active_support/core_ext/load_error.rb b/activesupport/lib/active_support/core_ext/load_error.rb
index d273487010..55177efdaf 100644
--- a/activesupport/lib/active_support/core_ext/load_error.rb
+++ b/activesupport/lib/active_support/core_ext/load_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class LoadError
   REGEXPS = [
     /^no such file to load -- (.+)$/i,
diff --git a/activesupport/lib/active_support/core_ext/marshal.rb b/activesupport/lib/active_support/core_ext/marshal.rb
index bba2b3be2e..13b1d0cf95 100644
--- a/activesupport/lib/active_support/core_ext/marshal.rb
+++ b/activesupport/lib/active_support/core_ext/marshal.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module MarshalWithAutoloading # :nodoc:
     def load(source, proc = nil)
diff --git a/activesupport/lib/active_support/core_ext/module.rb b/activesupport/lib/active_support/core_ext/module.rb
index 2930255557..6c304292eb 100644
--- a/activesupport/lib/active_support/core_ext/module.rb
+++ b/activesupport/lib/active_support/core_ext/module.rb
@@ -1,11 +1,12 @@
-require "active_support/core_ext/module/aliasing"
-require "active_support/core_ext/module/introspection"
-require "active_support/core_ext/module/anonymous"
-require "active_support/core_ext/module/reachable"
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/module/attribute_accessors_per_thread"
-require "active_support/core_ext/module/attr_internal"
-require "active_support/core_ext/module/concerning"
-require "active_support/core_ext/module/delegation"
-require "active_support/core_ext/module/deprecation"
-require "active_support/core_ext/module/remove_method"
+# frozen_string_literal: true
+require_relative "module/aliasing"
+require_relative "module/introspection"
+require_relative "module/anonymous"
+require_relative "module/reachable"
+require_relative "module/attribute_accessors"
+require_relative "module/attribute_accessors_per_thread"
+require_relative "module/attr_internal"
+require_relative "module/concerning"
+require_relative "module/delegation"
+require_relative "module/deprecation"
+require_relative "module/remove_method"
diff --git a/activesupport/lib/active_support/core_ext/module/aliasing.rb b/activesupport/lib/active_support/core_ext/module/aliasing.rb
index c48bd3354a..62eb9e4c76 100644
--- a/activesupport/lib/active_support/core_ext/module/aliasing.rb
+++ b/activesupport/lib/active_support/core_ext/module/aliasing.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
   # Allows you to make aliases for attributes, which includes
   # getter, setter, and a predicate.
diff --git a/activesupport/lib/active_support/core_ext/module/anonymous.rb b/activesupport/lib/active_support/core_ext/module/anonymous.rb
index 510c9a5430..7d10240199 100644
--- a/activesupport/lib/active_support/core_ext/module/anonymous.rb
+++ b/activesupport/lib/active_support/core_ext/module/anonymous.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
   # A module may or may not have a name.
   #
diff --git a/activesupport/lib/active_support/core_ext/module/attr_internal.rb b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
index 5081d5f7a3..8d37460dbc 100644
--- a/activesupport/lib/active_support/core_ext/module/attr_internal.rb
+++ b/activesupport/lib/active_support/core_ext/module/attr_internal.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
   # Declares an attribute reader backed by an internally-named instance variable.
   def attr_internal_reader(*attrs)
diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
index 2c24081eb9..430b1accbc 100644
--- a/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
+++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../array/extract_options"
+require_relative "../regexp"
 
 # Extends the module object with class/module and instance accessors for
 # class/module attributes, just like the native attr* accessors for instance
@@ -38,13 +39,10 @@ class Module
   #
   #   Person.new.hair_colors # => NoMethodError
   #
-  #
-  # Also, you can pass a block to set up the attribute with a default value.
+  # You can set a default value for the attribute.
   #
   #   module HairColors
-  #     mattr_reader :hair_colors do
-  #       [:brown, :black, :blonde, :red]
-  #     end
+  #     mattr_reader :hair_colors, default: [:brown, :black, :blonde, :red]
   #   end
   #
   #   class Person
@@ -52,8 +50,7 @@ class Module
   #   end
   #
   #   Person.new.hair_colors # => [:brown, :black, :blonde, :red]
-  def mattr_reader(*syms)
-    options = syms.extract_options!
+  def mattr_reader(*syms, instance_reader: true, instance_accessor: true, default: nil)
     syms.each do |sym|
       raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@ -64,14 +61,16 @@ class Module
         end
       EOS
 
-      unless options[:instance_reader] == false || options[:instance_accessor] == false
+      if instance_reader && instance_accessor
         class_eval(<<-EOS, __FILE__, __LINE__ + 1)
           def #{sym}
             @@#{sym}
           end
         EOS
       end
-      class_variable_set("@@#{sym}", yield) if block_given?
+
+      sym_default_value = (block_given? && default.nil?) ? yield : default
+      class_variable_set("@@#{sym}", sym_default_value) unless sym_default_value.nil?
     end
   end
   alias :cattr_reader :mattr_reader
@@ -107,12 +106,10 @@ class Module
   #
   #   Person.new.hair_colors = [:blonde, :red] # => NoMethodError
   #
-  # Also, you can pass a block to set up the attribute with a default value.
+  # You can set a default value for the attribute.
   #
   #   module HairColors
-  #     mattr_writer :hair_colors do
-  #       [:brown, :black, :blonde, :red]
-  #     end
+  #     mattr_writer :hair_colors, default: [:brown, :black, :blonde, :red]
   #   end
   #
   #   class Person
@@ -120,8 +117,7 @@ class Module
   #   end
   #
   #   Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
-  def mattr_writer(*syms)
-    options = syms.extract_options!
+  def mattr_writer(*syms, instance_writer: true, instance_accessor: true, default: nil)
     syms.each do |sym|
       raise NameError.new("invalid attribute name: #{sym}") unless /\A[_A-Za-z]\w*\z/.match?(sym)
       class_eval(<<-EOS, __FILE__, __LINE__ + 1)
@@ -132,14 +128,16 @@ class Module
         end
       EOS
 
-      unless options[:instance_writer] == false || options[:instance_accessor] == false
+      if instance_writer && instance_accessor
         class_eval(<<-EOS, __FILE__, __LINE__ + 1)
           def #{sym}=(obj)
             @@#{sym} = obj
           end
         EOS
       end
-      send("#{sym}=", yield) if block_given?
+
+      sym_default_value = (block_given? && default.nil?) ? yield : default
+      send("#{sym}=", sym_default_value) unless sym_default_value.nil?
     end
   end
   alias :cattr_writer :mattr_writer
@@ -197,12 +195,10 @@ class Module
   #   Person.new.hair_colors = [:brown]  # => NoMethodError
   #   Person.new.hair_colors             # => NoMethodError
   #
-  # Also you can pass a block to set up the attribute with a default value.
+  # You can set a default value for the attribute.
   #
   #   module HairColors
-  #     mattr_accessor :hair_colors do
-  #       [:brown, :black, :blonde, :red]
-  #     end
+  #     mattr_accessor :hair_colors, default: [:brown, :black, :blonde, :red]
   #   end
   #
   #   class Person
@@ -210,9 +206,9 @@ class Module
   #   end
   #
   #   Person.class_variable_get("@@hair_colors") # => [:brown, :black, :blonde, :red]
-  def mattr_accessor(*syms, &blk)
-    mattr_reader(*syms, &blk)
-    mattr_writer(*syms)
+  def mattr_accessor(*syms, instance_reader: true, instance_writer: true, instance_accessor: true, default: nil, &blk)
+    mattr_reader(*syms, instance_reader: instance_reader, instance_accessor: instance_accessor, default: default, &blk)
+    mattr_writer(*syms, instance_writer: instance_writer, instance_accessor: instance_accessor, default: default)
   end
   alias :cattr_accessor :mattr_accessor
 end
diff --git a/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb b/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb
index 1e82b4acc2..bc5d4b6dda 100644
--- a/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb
+++ b/activesupport/lib/active_support/core_ext/module/attribute_accessors_per_thread.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/array/extract_options"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../array/extract_options"
+require_relative "../regexp"
 
 # Extends the module object with class/module and instance accessors for
 # class/module attributes, just like the native attr* accessors for instance
diff --git a/activesupport/lib/active_support/core_ext/module/concerning.rb b/activesupport/lib/active_support/core_ext/module/concerning.rb
index 97b0a382ce..e4e49746b6 100644
--- a/activesupport/lib/active_support/core_ext/module/concerning.rb
+++ b/activesupport/lib/active_support/core_ext/module/concerning.rb
@@ -1,4 +1,5 @@
-require "active_support/concern"
+# frozen_string_literal: true
+require_relative "../../concern"
 
 class Module
   # = Bite-sized separation of concerns
diff --git a/activesupport/lib/active_support/core_ext/module/delegation.rb b/activesupport/lib/active_support/core_ext/module/delegation.rb
index 13f3894e6c..46c84eb509 100644
--- a/activesupport/lib/active_support/core_ext/module/delegation.rb
+++ b/activesupport/lib/active_support/core_ext/module/delegation.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "set"
-require "active_support/core_ext/regexp"
+require_relative "../regexp"
 
 class Module
   # Error generated by +delegate+ when a method is called on +nil+ and +allow_nil+
@@ -174,7 +175,7 @@ class Module
     to = to.to_s
     to = "self.#{to}" if DELEGATION_RESERVED_METHOD_NAMES.include?(to)
 
-    methods.each do |method|
+    methods.map do |method|
       # Attribute writer methods only accept one argument. Makes sure []=
       # methods still accept two arguments.
       definition = /[^\]]=$/.match?(method) ? "arg" : "*args, &block"
diff --git a/activesupport/lib/active_support/core_ext/module/deprecation.rb b/activesupport/lib/active_support/core_ext/module/deprecation.rb
index f3f2e7f5fc..98dfaad760 100644
--- a/activesupport/lib/active_support/core_ext/module/deprecation.rb
+++ b/activesupport/lib/active_support/core_ext/module/deprecation.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
   #   deprecate :foo
   #   deprecate bar: 'message'
diff --git a/activesupport/lib/active_support/core_ext/module/introspection.rb b/activesupport/lib/active_support/core_ext/module/introspection.rb
index ca20a6d4c5..69122885ec 100644
--- a/activesupport/lib/active_support/core_ext/module/introspection.rb
+++ b/activesupport/lib/active_support/core_ext/module/introspection.rb
@@ -1,4 +1,5 @@
-require "active_support/inflector"
+# frozen_string_literal: true
+require_relative "../../inflector"
 
 class Module
   # Returns the name of the module containing this one.
diff --git a/activesupport/lib/active_support/core_ext/module/reachable.rb b/activesupport/lib/active_support/core_ext/module/reachable.rb
index b89a38f26c..023894055f 100644
--- a/activesupport/lib/active_support/core_ext/module/reachable.rb
+++ b/activesupport/lib/active_support/core_ext/module/reachable.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/module/anonymous"
-require "active_support/core_ext/string/inflections"
+# frozen_string_literal: true
+require_relative "anonymous"
+require_relative "../string/inflections"
 
 class Module
   def reachable? #:nodoc:
diff --git a/activesupport/lib/active_support/core_ext/module/remove_method.rb b/activesupport/lib/active_support/core_ext/module/remove_method.rb
index d5ec16d68a..c17808b244 100644
--- a/activesupport/lib/active_support/core_ext/module/remove_method.rb
+++ b/activesupport/lib/active_support/core_ext/module/remove_method.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Module
   # Removes the named method, if it exists.
   def remove_possible_method(method)
diff --git a/activesupport/lib/active_support/core_ext/name_error.rb b/activesupport/lib/active_support/core_ext/name_error.rb
index 6b447d772b..1bcb6ded3c 100644
--- a/activesupport/lib/active_support/core_ext/name_error.rb
+++ b/activesupport/lib/active_support/core_ext/name_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class NameError
   # Extract the name of the missing constant from the exception message.
   #
diff --git a/activesupport/lib/active_support/core_ext/numeric.rb b/activesupport/lib/active_support/core_ext/numeric.rb
index 6062f9e3a8..6c407bc1ff 100644
--- a/activesupport/lib/active_support/core_ext/numeric.rb
+++ b/activesupport/lib/active_support/core_ext/numeric.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/numeric/bytes"
-require "active_support/core_ext/numeric/time"
-require "active_support/core_ext/numeric/inquiry"
-require "active_support/core_ext/numeric/conversions"
+# frozen_string_literal: true
+require_relative "numeric/bytes"
+require_relative "numeric/time"
+require_relative "numeric/inquiry"
+require_relative "numeric/conversions"
diff --git a/activesupport/lib/active_support/core_ext/numeric/bytes.rb b/activesupport/lib/active_support/core_ext/numeric/bytes.rb
index dfbca32474..23e1e39dd8 100644
--- a/activesupport/lib/active_support/core_ext/numeric/bytes.rb
+++ b/activesupport/lib/active_support/core_ext/numeric/bytes.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Numeric
   KILOBYTE = 1024
   MEGABYTE = KILOBYTE * 1024
diff --git a/activesupport/lib/active_support/core_ext/numeric/conversions.rb b/activesupport/lib/active_support/core_ext/numeric/conversions.rb
index 4f6621693e..b8cff9aeb9 100644
--- a/activesupport/lib/active_support/core_ext/numeric/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/numeric/conversions.rb
@@ -1,6 +1,7 @@
-require "active_support/core_ext/big_decimal/conversions"
-require "active_support/number_helper"
-require "active_support/core_ext/module/deprecation"
+# frozen_string_literal: true
+require_relative "../big_decimal/conversions"
+require_relative "../../number_helper"
+require_relative "../module/deprecation"
 
 module ActiveSupport::NumericWithFormat
   # Provides options for converting numbers into formatted strings.
diff --git a/activesupport/lib/active_support/core_ext/numeric/inquiry.rb b/activesupport/lib/active_support/core_ext/numeric/inquiry.rb
index ec79701189..baccf87848 100644
--- a/activesupport/lib/active_support/core_ext/numeric/inquiry.rb
+++ b/activesupport/lib/active_support/core_ext/numeric/inquiry.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 unless 1.respond_to?(:positive?) # TODO: Remove this file when we drop support to ruby < 2.3
   class Numeric
     # Returns true if the number is positive.
diff --git a/activesupport/lib/active_support/core_ext/numeric/time.rb b/activesupport/lib/active_support/core_ext/numeric/time.rb
index 2e6c70d418..382a8cd162 100644
--- a/activesupport/lib/active_support/core_ext/numeric/time.rb
+++ b/activesupport/lib/active_support/core_ext/numeric/time.rb
@@ -1,8 +1,9 @@
-require "active_support/duration"
-require "active_support/core_ext/time/calculations"
-require "active_support/core_ext/time/acts_like"
-require "active_support/core_ext/date/calculations"
-require "active_support/core_ext/date/acts_like"
+# frozen_string_literal: true
+require_relative "../../duration"
+require_relative "../time/calculations"
+require_relative "../time/acts_like"
+require_relative "../date/calculations"
+require_relative "../date/acts_like"
 
 class Numeric
   # Enables the use of time calculations and declarations, like 45.minutes + 2.hours + 4.years.
diff --git a/activesupport/lib/active_support/core_ext/object.rb b/activesupport/lib/active_support/core_ext/object.rb
index 58bbf78601..cd350d5c45 100644
--- a/activesupport/lib/active_support/core_ext/object.rb
+++ b/activesupport/lib/active_support/core_ext/object.rb
@@ -1,14 +1,15 @@
-require "active_support/core_ext/object/acts_like"
-require "active_support/core_ext/object/blank"
-require "active_support/core_ext/object/duplicable"
-require "active_support/core_ext/object/deep_dup"
-require "active_support/core_ext/object/try"
-require "active_support/core_ext/object/inclusion"
+# frozen_string_literal: true
+require_relative "object/acts_like"
+require_relative "object/blank"
+require_relative "object/duplicable"
+require_relative "object/deep_dup"
+require_relative "object/try"
+require_relative "object/inclusion"
 
-require "active_support/core_ext/object/conversions"
-require "active_support/core_ext/object/instance_variables"
+require_relative "object/conversions"
+require_relative "object/instance_variables"
 
-require "active_support/core_ext/object/json"
-require "active_support/core_ext/object/to_param"
-require "active_support/core_ext/object/to_query"
-require "active_support/core_ext/object/with_options"
+require_relative "object/json"
+require_relative "object/to_param"
+require_relative "object/to_query"
+require_relative "object/with_options"
diff --git a/activesupport/lib/active_support/core_ext/object/acts_like.rb b/activesupport/lib/active_support/core_ext/object/acts_like.rb
index 3912cc5ace..b856e1ba16 100644
--- a/activesupport/lib/active_support/core_ext/object/acts_like.rb
+++ b/activesupport/lib/active_support/core_ext/object/acts_like.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Object
   # A duck-type assistant method. For example, Active Support extends Date
   # to define an <tt>acts_like_date?</tt> method, and extends Time to define
diff --git a/activesupport/lib/active_support/core_ext/object/blank.rb b/activesupport/lib/active_support/core_ext/object/blank.rb
index bdb50ee291..fd10e1bf72 100644
--- a/activesupport/lib/active_support/core_ext/object/blank.rb
+++ b/activesupport/lib/active_support/core_ext/object/blank.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../regexp"
 
 class Object
   # An object is blank if it's false, empty, or a whitespace string.
diff --git a/activesupport/lib/active_support/core_ext/object/conversions.rb b/activesupport/lib/active_support/core_ext/object/conversions.rb
index 918ebcdc9f..846e3a4fa7 100644
--- a/activesupport/lib/active_support/core_ext/object/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/object/conversions.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/to_param"
-require "active_support/core_ext/object/to_query"
-require "active_support/core_ext/array/conversions"
-require "active_support/core_ext/hash/conversions"
+# frozen_string_literal: true
+require_relative "to_param"
+require_relative "to_query"
+require_relative "../array/conversions"
+require_relative "../hash/conversions"
diff --git a/activesupport/lib/active_support/core_ext/object/deep_dup.rb b/activesupport/lib/active_support/core_ext/object/deep_dup.rb
index 5ac649e552..ac7537b500 100644
--- a/activesupport/lib/active_support/core_ext/object/deep_dup.rb
+++ b/activesupport/lib/active_support/core_ext/object/deep_dup.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/duplicable"
+# frozen_string_literal: true
+require_relative "duplicable"
 
 class Object
   # Returns a deep copy of object if it's duplicable. If it's
diff --git a/activesupport/lib/active_support/core_ext/object/duplicable.rb b/activesupport/lib/active_support/core_ext/object/duplicable.rb
index b028df97ee..0838b1fb70 100644
--- a/activesupport/lib/active_support/core_ext/object/duplicable.rb
+++ b/activesupport/lib/active_support/core_ext/object/duplicable.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 #--
 # Most objects are cloneable, but not all. For example you can't dup methods:
 #
diff --git a/activesupport/lib/active_support/core_ext/object/inclusion.rb b/activesupport/lib/active_support/core_ext/object/inclusion.rb
index 98bf820d36..525ddcb575 100644
--- a/activesupport/lib/active_support/core_ext/object/inclusion.rb
+++ b/activesupport/lib/active_support/core_ext/object/inclusion.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Object
   # Returns true if this object is included in the argument. Argument must be
   # any object which responds to +#include?+. Usage:
diff --git a/activesupport/lib/active_support/core_ext/object/instance_variables.rb b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
index 593a7a4940..0a06125210 100644
--- a/activesupport/lib/active_support/core_ext/object/instance_variables.rb
+++ b/activesupport/lib/active_support/core_ext/object/instance_variables.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Object
   # Returns a hash with string keys that maps instance variable names without "@" to their
   # corresponding values.
diff --git a/activesupport/lib/active_support/core_ext/object/json.rb b/activesupport/lib/active_support/core_ext/object/json.rb
index 1c4d181443..3c8846029f 100644
--- a/activesupport/lib/active_support/core_ext/object/json.rb
+++ b/activesupport/lib/active_support/core_ext/object/json.rb
@@ -1,16 +1,17 @@
+# frozen_string_literal: true
 # Hack to load json gem first so we can overwrite its to_json.
 require "json"
 require "bigdecimal"
 require "uri/generic"
 require "pathname"
-require "active_support/core_ext/big_decimal/conversions" # for #to_s
-require "active_support/core_ext/hash/except"
-require "active_support/core_ext/hash/slice"
-require "active_support/core_ext/object/instance_variables"
+require_relative "../big_decimal/conversions" # for #to_s
+require_relative "../hash/except"
+require_relative "../hash/slice"
+require_relative "instance_variables"
 require "time"
-require "active_support/core_ext/time/conversions"
-require "active_support/core_ext/date_time/conversions"
-require "active_support/core_ext/date/conversions"
+require_relative "../time/conversions"
+require_relative "../date_time/conversions"
+require_relative "../date/conversions"
 
 # The JSON gem adds a few modules to Ruby core classes containing :to_json definition, overwriting
 # their default behavior. That said, we need to define the basic to_json method in all of them,
diff --git a/activesupport/lib/active_support/core_ext/object/to_param.rb b/activesupport/lib/active_support/core_ext/object/to_param.rb
index 5eeaf03163..0b172829db 100644
--- a/activesupport/lib/active_support/core_ext/object/to_param.rb
+++ b/activesupport/lib/active_support/core_ext/object/to_param.rb
@@ -1 +1,2 @@
-require "active_support/core_ext/object/to_query"
+# frozen_string_literal: true
+require_relative "to_query"
diff --git a/activesupport/lib/active_support/core_ext/object/to_query.rb b/activesupport/lib/active_support/core_ext/object/to_query.rb
index a3a3abacbb..f85e0eaa6f 100644
--- a/activesupport/lib/active_support/core_ext/object/to_query.rb
+++ b/activesupport/lib/active_support/core_ext/object/to_query.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "cgi"
 
 class Object
diff --git a/activesupport/lib/active_support/core_ext/object/try.rb b/activesupport/lib/active_support/core_ext/object/try.rb
index b2be619b2d..952fba4541 100644
--- a/activesupport/lib/active_support/core_ext/object/try.rb
+++ b/activesupport/lib/active_support/core_ext/object/try.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "delegate"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/core_ext/object/with_options.rb b/activesupport/lib/active_support/core_ext/object/with_options.rb
index 3a44e08630..22a0034d7d 100644
--- a/activesupport/lib/active_support/core_ext/object/with_options.rb
+++ b/activesupport/lib/active_support/core_ext/object/with_options.rb
@@ -1,4 +1,5 @@
-require "active_support/option_merger"
+# frozen_string_literal: true
+require_relative "../../option_merger"
 
 class Object
   # An elegant way to factor duplication out of options passed to a series of
diff --git a/activesupport/lib/active_support/core_ext/range.rb b/activesupport/lib/active_support/core_ext/range.rb
index 3190e3ff76..db4c63380b 100644
--- a/activesupport/lib/active_support/core_ext/range.rb
+++ b/activesupport/lib/active_support/core_ext/range.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/range/conversions"
-require "active_support/core_ext/range/include_range"
-require "active_support/core_ext/range/overlaps"
-require "active_support/core_ext/range/each"
+# frozen_string_literal: true
+require_relative "range/conversions"
+require_relative "range/include_range"
+require_relative "range/overlaps"
+require_relative "range/each"
diff --git a/activesupport/lib/active_support/core_ext/range/conversions.rb b/activesupport/lib/active_support/core_ext/range/conversions.rb
index 69ea046cb6..5038a15cdf 100644
--- a/activesupport/lib/active_support/core_ext/range/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/range/conversions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport::RangeWithFormat
   RANGE_FORMATS = {
     db: Proc.new { |start, stop| "BETWEEN '#{start.to_s(:db)}' AND '#{stop.to_s(:db)}'" }
diff --git a/activesupport/lib/active_support/core_ext/range/each.rb b/activesupport/lib/active_support/core_ext/range/each.rb
index dc6dad5ced..aeea8c867b 100644
--- a/activesupport/lib/active_support/core_ext/range/each.rb
+++ b/activesupport/lib/active_support/core_ext/range/each.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module EachTimeWithZone #:nodoc:
     def each(&block)
diff --git a/activesupport/lib/active_support/core_ext/range/include_range.rb b/activesupport/lib/active_support/core_ext/range/include_range.rb
index c69e1e3fb9..d307750a23 100644
--- a/activesupport/lib/active_support/core_ext/range/include_range.rb
+++ b/activesupport/lib/active_support/core_ext/range/include_range.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module IncludeWithRange #:nodoc:
     # Extends the default Range#include? to support range comparisons.
diff --git a/activesupport/lib/active_support/core_ext/range/overlaps.rb b/activesupport/lib/active_support/core_ext/range/overlaps.rb
index 603657c180..ecdfbd803b 100644
--- a/activesupport/lib/active_support/core_ext/range/overlaps.rb
+++ b/activesupport/lib/active_support/core_ext/range/overlaps.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Range
   # Compare two ranges and see if they overlap each other
   #  (1..5).overlaps?(4..6) # => true
diff --git a/activesupport/lib/active_support/core_ext/regexp.rb b/activesupport/lib/active_support/core_ext/regexp.rb
index d77d01bf42..23b337ba67 100644
--- a/activesupport/lib/active_support/core_ext/regexp.rb
+++ b/activesupport/lib/active_support/core_ext/regexp.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class Regexp #:nodoc:
   def multiline?
     options & MULTILINE == MULTILINE
diff --git a/activesupport/lib/active_support/core_ext/securerandom.rb b/activesupport/lib/active_support/core_ext/securerandom.rb
index a57685bea1..033ac356bd 100644
--- a/activesupport/lib/active_support/core_ext/securerandom.rb
+++ b/activesupport/lib/active_support/core_ext/securerandom.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "securerandom"
 
 module SecureRandom
diff --git a/activesupport/lib/active_support/core_ext/string.rb b/activesupport/lib/active_support/core_ext/string.rb
index 4cb3200875..cefd82fa20 100644
--- a/activesupport/lib/active_support/core_ext/string.rb
+++ b/activesupport/lib/active_support/core_ext/string.rb
@@ -1,13 +1,14 @@
-require "active_support/core_ext/string/conversions"
-require "active_support/core_ext/string/filters"
-require "active_support/core_ext/string/multibyte"
-require "active_support/core_ext/string/starts_ends_with"
-require "active_support/core_ext/string/inflections"
-require "active_support/core_ext/string/access"
-require "active_support/core_ext/string/behavior"
-require "active_support/core_ext/string/output_safety"
-require "active_support/core_ext/string/exclude"
-require "active_support/core_ext/string/strip"
-require "active_support/core_ext/string/inquiry"
-require "active_support/core_ext/string/indent"
-require "active_support/core_ext/string/zones"
+# frozen_string_literal: true
+require_relative "string/conversions"
+require_relative "string/filters"
+require_relative "string/multibyte"
+require_relative "string/starts_ends_with"
+require_relative "string/inflections"
+require_relative "string/access"
+require_relative "string/behavior"
+require_relative "string/output_safety"
+require_relative "string/exclude"
+require_relative "string/strip"
+require_relative "string/inquiry"
+require_relative "string/indent"
+require_relative "string/zones"
diff --git a/activesupport/lib/active_support/core_ext/string/access.rb b/activesupport/lib/active_support/core_ext/string/access.rb
index 6133826f37..11f4bf8052 100644
--- a/activesupport/lib/active_support/core_ext/string/access.rb
+++ b/activesupport/lib/active_support/core_ext/string/access.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # If you pass a single integer, returns a substring of one character at that
   # position. The first character of the string is at position 0, the next at
diff --git a/activesupport/lib/active_support/core_ext/string/behavior.rb b/activesupport/lib/active_support/core_ext/string/behavior.rb
index 710f1f4670..e63888991d 100644
--- a/activesupport/lib/active_support/core_ext/string/behavior.rb
+++ b/activesupport/lib/active_support/core_ext/string/behavior.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # Enables more predictable duck-typing on String-like classes. See <tt>Object#acts_like?</tt>.
   def acts_like_string?
diff --git a/activesupport/lib/active_support/core_ext/string/conversions.rb b/activesupport/lib/active_support/core_ext/string/conversions.rb
index 221b4969cc..a0b771f41e 100644
--- a/activesupport/lib/active_support/core_ext/string/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/string/conversions.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "date"
-require "active_support/core_ext/time/calculations"
+require_relative "../time/calculations"
 
 class String
   # Converts a string to a Time value.
diff --git a/activesupport/lib/active_support/core_ext/string/exclude.rb b/activesupport/lib/active_support/core_ext/string/exclude.rb
index 0ac684f6ee..2893a6eeed 100644
--- a/activesupport/lib/active_support/core_ext/string/exclude.rb
+++ b/activesupport/lib/active_support/core_ext/string/exclude.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # The inverse of <tt>String#include?</tt>. Returns true if the string
   # does not include the other string.
diff --git a/activesupport/lib/active_support/core_ext/string/filters.rb b/activesupport/lib/active_support/core_ext/string/filters.rb
index a9ec2eb842..e05cf024f6 100644
--- a/activesupport/lib/active_support/core_ext/string/filters.rb
+++ b/activesupport/lib/active_support/core_ext/string/filters.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # Returns the string, first removing all whitespace on both ends of
   # the string, and then changing remaining consecutive whitespace
diff --git a/activesupport/lib/active_support/core_ext/string/indent.rb b/activesupport/lib/active_support/core_ext/string/indent.rb
index d7b58301d3..a38198a8e6 100644
--- a/activesupport/lib/active_support/core_ext/string/indent.rb
+++ b/activesupport/lib/active_support/core_ext/string/indent.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # Same as +indent+, except it indents the receiver in-place.
   #
diff --git a/activesupport/lib/active_support/core_ext/string/inflections.rb b/activesupport/lib/active_support/core_ext/string/inflections.rb
index b27cfe53f4..78caa0832f 100644
--- a/activesupport/lib/active_support/core_ext/string/inflections.rb
+++ b/activesupport/lib/active_support/core_ext/string/inflections.rb
@@ -1,5 +1,6 @@
-require "active_support/inflector/methods"
-require "active_support/inflector/transliterate"
+# frozen_string_literal: true
+require_relative "../../inflector/methods"
+require_relative "../../inflector/transliterate"
 
 # String inflections define new methods on the String class to transform names for different purposes.
 # For instance, you can figure out the name of a table from the name of a class.
diff --git a/activesupport/lib/active_support/core_ext/string/inquiry.rb b/activesupport/lib/active_support/core_ext/string/inquiry.rb
index c95d83beae..0fe532fb8c 100644
--- a/activesupport/lib/active_support/core_ext/string/inquiry.rb
+++ b/activesupport/lib/active_support/core_ext/string/inquiry.rb
@@ -1,4 +1,5 @@
-require "active_support/string_inquirer"
+# frozen_string_literal: true
+require_relative "../../string_inquirer"
 
 class String
   # Wraps the current string in the <tt>ActiveSupport::StringInquirer</tt> class,
diff --git a/activesupport/lib/active_support/core_ext/string/multibyte.rb b/activesupport/lib/active_support/core_ext/string/multibyte.rb
index 1c73182259..403e4be011 100644
--- a/activesupport/lib/active_support/core_ext/string/multibyte.rb
+++ b/activesupport/lib/active_support/core_ext/string/multibyte.rb
@@ -1,4 +1,5 @@
-require "active_support/multibyte"
+# frozen_string_literal: true
+require_relative "../../multibyte"
 
 class String
   # == Multibyte proxy
diff --git a/activesupport/lib/active_support/core_ext/string/output_safety.rb b/activesupport/lib/active_support/core_ext/string/output_safety.rb
index 94ce3f6a61..4bfc582eb5 100644
--- a/activesupport/lib/active_support/core_ext/string/output_safety.rb
+++ b/activesupport/lib/active_support/core_ext/string/output_safety.rb
@@ -1,6 +1,7 @@
+# frozen_string_literal: true
 require "erb"
-require "active_support/core_ext/kernel/singleton_class"
-require "active_support/multibyte/unicode"
+require_relative "../kernel/singleton_class"
+require_relative "../../multibyte/unicode"
 
 class ERB
   module Util
diff --git a/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb b/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb
index 641acf62d0..f072fbf7d7 100644
--- a/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb
+++ b/activesupport/lib/active_support/core_ext/string/starts_ends_with.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   alias_method :starts_with?, :start_with?
   alias_method :ends_with?, :end_with?
diff --git a/activesupport/lib/active_support/core_ext/string/strip.rb b/activesupport/lib/active_support/core_ext/string/strip.rb
index bb62e6c0ba..979b6bd767 100644
--- a/activesupport/lib/active_support/core_ext/string/strip.rb
+++ b/activesupport/lib/active_support/core_ext/string/strip.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class String
   # Strips indentation in heredocs.
   #
diff --git a/activesupport/lib/active_support/core_ext/string/zones.rb b/activesupport/lib/active_support/core_ext/string/zones.rb
index de5a28e4f7..a911fdab3c 100644
--- a/activesupport/lib/active_support/core_ext/string/zones.rb
+++ b/activesupport/lib/active_support/core_ext/string/zones.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/string/conversions"
-require "active_support/core_ext/time/zones"
+# frozen_string_literal: true
+require_relative "conversions"
+require_relative "../time/zones"
 
 class String
   # Converts String to a TimeWithZone in the current zone if Time.zone or Time.zone_default
diff --git a/activesupport/lib/active_support/core_ext/time.rb b/activesupport/lib/active_support/core_ext/time.rb
index b1ae4a45d9..cfa9b82b06 100644
--- a/activesupport/lib/active_support/core_ext/time.rb
+++ b/activesupport/lib/active_support/core_ext/time.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/time/acts_like"
-require "active_support/core_ext/time/calculations"
-require "active_support/core_ext/time/compatibility"
-require "active_support/core_ext/time/conversions"
-require "active_support/core_ext/time/zones"
+# frozen_string_literal: true
+require_relative "time/acts_like"
+require_relative "time/calculations"
+require_relative "time/compatibility"
+require_relative "time/conversions"
+require_relative "time/zones"
diff --git a/activesupport/lib/active_support/core_ext/time/acts_like.rb b/activesupport/lib/active_support/core_ext/time/acts_like.rb
index cf4b2539c5..776456506c 100644
--- a/activesupport/lib/active_support/core_ext/time/acts_like.rb
+++ b/activesupport/lib/active_support/core_ext/time/acts_like.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/acts_like"
+# frozen_string_literal: true
+require_relative "../object/acts_like"
 
 class Time
   # Duck-types as a Time-like class. See Object#acts_like?.
diff --git a/activesupport/lib/active_support/core_ext/time/calculations.rb b/activesupport/lib/active_support/core_ext/time/calculations.rb
index d3f23f4663..4cfb702674 100644
--- a/activesupport/lib/active_support/core_ext/time/calculations.rb
+++ b/activesupport/lib/active_support/core_ext/time/calculations.rb
@@ -1,9 +1,10 @@
-require "active_support/duration"
-require "active_support/core_ext/time/conversions"
-require "active_support/time_with_zone"
-require "active_support/core_ext/time/zones"
-require "active_support/core_ext/date_and_time/calculations"
-require "active_support/core_ext/date/calculations"
+# frozen_string_literal: true
+require_relative "../../duration"
+require_relative "conversions"
+require_relative "../../time_with_zone"
+require_relative "zones"
+require_relative "../date_and_time/calculations"
+require_relative "../date/calculations"
 
 class Time
   include DateAndTime::Calculations
diff --git a/activesupport/lib/active_support/core_ext/time/compatibility.rb b/activesupport/lib/active_support/core_ext/time/compatibility.rb
index 45e86b77ce..ce69e5f478 100644
--- a/activesupport/lib/active_support/core_ext/time/compatibility.rb
+++ b/activesupport/lib/active_support/core_ext/time/compatibility.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/date_and_time/compatibility"
-require "active_support/core_ext/module/remove_method"
+# frozen_string_literal: true
+require_relative "../date_and_time/compatibility"
+require_relative "../module/remove_method"
 
 class Time
   include DateAndTime::Compatibility
diff --git a/activesupport/lib/active_support/core_ext/time/conversions.rb b/activesupport/lib/active_support/core_ext/time/conversions.rb
index 595bda6b4f..5cb0f9c980 100644
--- a/activesupport/lib/active_support/core_ext/time/conversions.rb
+++ b/activesupport/lib/active_support/core_ext/time/conversions.rb
@@ -1,5 +1,6 @@
-require "active_support/inflector/methods"
-require "active_support/values/time_zone"
+# frozen_string_literal: true
+require_relative "../../inflector/methods"
+require_relative "../../values/time_zone"
 
 class Time
   DATE_FORMATS = {
diff --git a/activesupport/lib/active_support/core_ext/time/zones.rb b/activesupport/lib/active_support/core_ext/time/zones.rb
index 87b5ad903a..3794eab3f5 100644
--- a/activesupport/lib/active_support/core_ext/time/zones.rb
+++ b/activesupport/lib/active_support/core_ext/time/zones.rb
@@ -1,6 +1,7 @@
-require "active_support/time_with_zone"
-require "active_support/core_ext/time/acts_like"
-require "active_support/core_ext/date_and_time/zones"
+# frozen_string_literal: true
+require_relative "../../time_with_zone"
+require_relative "acts_like"
+require_relative "../date_and_time/zones"
 
 class Time
   include DateAndTime::Zones
diff --git a/activesupport/lib/active_support/core_ext/uri.rb b/activesupport/lib/active_support/core_ext/uri.rb
index 342a5fcd52..f93dbdf2cd 100644
--- a/activesupport/lib/active_support/core_ext/uri.rb
+++ b/activesupport/lib/active_support/core_ext/uri.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "uri"
 str = "\xE6\x97\xA5\xE6\x9C\xAC\xE8\xAA\x9E" # Ni-ho-nn-go in UTF-8, means Japanese.
 parser = URI::Parser.new
diff --git a/activesupport/lib/active_support/current_attributes.rb b/activesupport/lib/active_support/current_attributes.rb
index 872b0663c7..1857700486 100644
--- a/activesupport/lib/active_support/current_attributes.rb
+++ b/activesupport/lib/active_support/current_attributes.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # Abstract super class that provides a thread-isolated attributes singleton, which resets automatically
   # before and after each request. This allows you to keep all the per-request attributes easily
diff --git a/activesupport/lib/active_support/dependencies.rb b/activesupport/lib/active_support/dependencies.rb
index e125b657f2..a11d4a834b 100644
--- a/activesupport/lib/active_support/dependencies.rb
+++ b/activesupport/lib/active_support/dependencies.rb
@@ -1,25 +1,25 @@
+# frozen_string_literal: true
 require "set"
 require "thread"
 require "concurrent/map"
 require "pathname"
-require "active_support/core_ext/module/aliasing"
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/module/introspection"
-require "active_support/core_ext/module/anonymous"
-require "active_support/core_ext/object/blank"
-require "active_support/core_ext/kernel/reporting"
-require "active_support/core_ext/load_error"
-require "active_support/core_ext/name_error"
-require "active_support/core_ext/string/starts_ends_with"
-require "active_support/dependencies/interlock"
-require "active_support/inflector"
+require_relative "core_ext/module/aliasing"
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/module/introspection"
+require_relative "core_ext/module/anonymous"
+require_relative "core_ext/object/blank"
+require_relative "core_ext/kernel/reporting"
+require_relative "core_ext/load_error"
+require_relative "core_ext/name_error"
+require_relative "core_ext/string/starts_ends_with"
+require_relative "dependencies/interlock"
+require_relative "inflector"
 
 module ActiveSupport #:nodoc:
   module Dependencies #:nodoc:
     extend self
 
-    mattr_accessor :interlock
-    self.interlock = Interlock.new
+    mattr_accessor :interlock, default: Interlock.new
 
     # :doc:
 
@@ -46,46 +46,37 @@ module ActiveSupport #:nodoc:
     # :nodoc:
 
     # Should we turn on Ruby warnings on the first load of dependent files?
-    mattr_accessor :warnings_on_first_load
-    self.warnings_on_first_load = false
+    mattr_accessor :warnings_on_first_load, default: false
 
     # All files ever loaded.
-    mattr_accessor :history
-    self.history = Set.new
+    mattr_accessor :history, default: Set.new
 
     # All files currently loaded.
-    mattr_accessor :loaded
-    self.loaded = Set.new
+    mattr_accessor :loaded, default: Set.new
 
     # Stack of files being loaded.
-    mattr_accessor :loading
-    self.loading = []
+    mattr_accessor :loading, default: []
 
     # Should we load files or require them?
-    mattr_accessor :mechanism
-    self.mechanism = ENV["NO_RELOAD"] ? :require : :load
+    mattr_accessor :mechanism, default: ENV["NO_RELOAD"] ? :require : :load
 
     # The set of directories from which we may automatically load files. Files
     # under these directories will be reloaded on each request in development mode,
     # unless the directory also appears in autoload_once_paths.
-    mattr_accessor :autoload_paths
-    self.autoload_paths = []
+    mattr_accessor :autoload_paths, default: []
 
     # The set of directories from which automatically loaded constants are loaded
     # only once. All directories in this set must also be present in +autoload_paths+.
-    mattr_accessor :autoload_once_paths
-    self.autoload_once_paths = []
+    mattr_accessor :autoload_once_paths, default: []
 
     # An array of qualified constant names that have been loaded. Adding a name
     # to this array will cause it to be unloaded the next time Dependencies are
     # cleared.
-    mattr_accessor :autoloaded_constants
-    self.autoloaded_constants = []
+    mattr_accessor :autoloaded_constants, default: []
 
     # An array of constant names that need to be unloaded on every request. Used
     # to allow arbitrary constants to be marked for unloading.
-    mattr_accessor :explicitly_unloadable_constants
-    self.explicitly_unloadable_constants = []
+    mattr_accessor :explicitly_unloadable_constants, default: []
 
     # The WatchStack keeps a stack of the modules being watched as files are
     # loaded. If a file in the process of being loaded (parent.rb) triggers the
@@ -175,8 +166,7 @@ module ActiveSupport #:nodoc:
     end
 
     # An internal stack used to record which constants are loaded by any block.
-    mattr_accessor :constant_watch_stack
-    self.constant_watch_stack = WatchStack.new
+    mattr_accessor :constant_watch_stack, default: WatchStack.new
 
     # Module includes this module.
     module ModuleConstMissing #:nodoc:
diff --git a/activesupport/lib/active_support/dependencies/autoload.rb b/activesupport/lib/active_support/dependencies/autoload.rb
index 13036d521d..fcf550be3d 100644
--- a/activesupport/lib/active_support/dependencies/autoload.rb
+++ b/activesupport/lib/active_support/dependencies/autoload.rb
@@ -1,4 +1,5 @@
-require "active_support/inflector/methods"
+# frozen_string_literal: true
+require_relative "../inflector/methods"
 
 module ActiveSupport
   # Autoload and eager load conveniences for your library.
diff --git a/activesupport/lib/active_support/dependencies/interlock.rb b/activesupport/lib/active_support/dependencies/interlock.rb
index e4e18439c5..0d80484c00 100644
--- a/activesupport/lib/active_support/dependencies/interlock.rb
+++ b/activesupport/lib/active_support/dependencies/interlock.rb
@@ -1,4 +1,5 @@
-require "active_support/concurrency/share_lock"
+# frozen_string_literal: true
+require_relative "../concurrency/share_lock"
 
 module ActiveSupport #:nodoc:
   module Dependencies #:nodoc:
diff --git a/activesupport/lib/active_support/deprecation.rb b/activesupport/lib/active_support/deprecation.rb
index 35cddcfde6..3e914de316 100644
--- a/activesupport/lib/active_support/deprecation.rb
+++ b/activesupport/lib/active_support/deprecation.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "singleton"
 
 module ActiveSupport
@@ -12,13 +13,13 @@ module ActiveSupport
     # a circular require warning for active_support/deprecation.rb.
     #
     # So, we define the constant first, and load dependencies later.
-    require "active_support/deprecation/instance_delegator"
-    require "active_support/deprecation/behaviors"
-    require "active_support/deprecation/reporting"
-    require "active_support/deprecation/constant_accessor"
-    require "active_support/deprecation/method_wrappers"
-    require "active_support/deprecation/proxy_wrappers"
-    require "active_support/core_ext/module/deprecation"
+    require_relative "deprecation/instance_delegator"
+    require_relative "deprecation/behaviors"
+    require_relative "deprecation/reporting"
+    require_relative "deprecation/constant_accessor"
+    require_relative "deprecation/method_wrappers"
+    require_relative "deprecation/proxy_wrappers"
+    require_relative "core_ext/module/deprecation"
 
     include Singleton
     include InstanceDelegator
@@ -33,7 +34,7 @@ module ActiveSupport
     # and the second is a library name.
     #
     #   ActiveSupport::Deprecation.new('2.0', 'MyLibrary')
-    def initialize(deprecation_horizon = "5.3", gem_name = "Rails")
+    def initialize(deprecation_horizon = "6.0", gem_name = "Rails")
       self.gem_name = gem_name
       self.deprecation_horizon = deprecation_horizon
       # By default, warnings are not silenced and debugging is off.
diff --git a/activesupport/lib/active_support/deprecation/behaviors.rb b/activesupport/lib/active_support/deprecation/behaviors.rb
index a9a182f212..5b7f67db53 100644
--- a/activesupport/lib/active_support/deprecation/behaviors.rb
+++ b/activesupport/lib/active_support/deprecation/behaviors.rb
@@ -1,4 +1,5 @@
-require "active_support/notifications"
+# frozen_string_literal: true
+require_relative "../notifications"
 
 module ActiveSupport
   # Raised when <tt>ActiveSupport::Deprecation::Behavior#behavior</tt> is set with <tt>:raise</tt>.
@@ -25,7 +26,7 @@ module ActiveSupport
             if defined?(Rails.logger) && Rails.logger
               Rails.logger
             else
-              require "active_support/logger"
+              require_relative "../logger"
               ActiveSupport::Logger.new($stderr)
             end
         logger.warn message
diff --git a/activesupport/lib/active_support/deprecation/constant_accessor.rb b/activesupport/lib/active_support/deprecation/constant_accessor.rb
index 2b19de365f..17850a2b39 100644
--- a/activesupport/lib/active_support/deprecation/constant_accessor.rb
+++ b/activesupport/lib/active_support/deprecation/constant_accessor.rb
@@ -1,4 +1,5 @@
-require "active_support/inflector/methods"
+# frozen_string_literal: true
+require_relative "../inflector/methods"
 
 module ActiveSupport
   class Deprecation
diff --git a/activesupport/lib/active_support/deprecation/instance_delegator.rb b/activesupport/lib/active_support/deprecation/instance_delegator.rb
index 6d390f3b37..4a62df4714 100644
--- a/activesupport/lib/active_support/deprecation/instance_delegator.rb
+++ b/activesupport/lib/active_support/deprecation/instance_delegator.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/kernel/singleton_class"
-require "active_support/core_ext/module/delegation"
+# frozen_string_literal: true
+require_relative "../core_ext/kernel/singleton_class"
+require_relative "../core_ext/module/delegation"
 
 module ActiveSupport
   class Deprecation
diff --git a/activesupport/lib/active_support/deprecation/method_wrappers.rb b/activesupport/lib/active_support/deprecation/method_wrappers.rb
index 930d71e8d2..94c7960a9d 100644
--- a/activesupport/lib/active_support/deprecation/method_wrappers.rb
+++ b/activesupport/lib/active_support/deprecation/method_wrappers.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/module/aliasing"
-require "active_support/core_ext/array/extract_options"
+# frozen_string_literal: true
+require_relative "../core_ext/module/aliasing"
+require_relative "../core_ext/array/extract_options"
 
 module ActiveSupport
   class Deprecation
diff --git a/activesupport/lib/active_support/deprecation/proxy_wrappers.rb b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
index ce39e9a232..cd3d7dcad4 100644
--- a/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
+++ b/activesupport/lib/active_support/deprecation/proxy_wrappers.rb
@@ -1,5 +1,6 @@
-require "active_support/inflector/methods"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../inflector/methods"
+require_relative "../core_ext/regexp"
 
 module ActiveSupport
   class Deprecation
diff --git a/activesupport/lib/active_support/deprecation/reporting.rb b/activesupport/lib/active_support/deprecation/reporting.rb
index 140bdccbb3..f190e47b64 100644
--- a/activesupport/lib/active_support/deprecation/reporting.rb
+++ b/activesupport/lib/active_support/deprecation/reporting.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "rbconfig"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/descendants_tracker.rb b/activesupport/lib/active_support/descendants_tracker.rb
index 27861e01d0..4f759f2f26 100644
--- a/activesupport/lib/active_support/descendants_tracker.rb
+++ b/activesupport/lib/active_support/descendants_tracker.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # This module provides an internal implementation to track descendants
   # which is faster than iterating through ObjectSpace.
diff --git a/activesupport/lib/active_support/duration.rb b/activesupport/lib/active_support/duration.rb
index 39deb2313f..15d550e3ee 100644
--- a/activesupport/lib/active_support/duration.rb
+++ b/activesupport/lib/active_support/duration.rb
@@ -1,8 +1,9 @@
-require "active_support/core_ext/array/conversions"
-require "active_support/core_ext/module/delegation"
-require "active_support/core_ext/object/acts_like"
-require "active_support/core_ext/string/filters"
-require "active_support/deprecation"
+# frozen_string_literal: true
+require_relative "core_ext/array/conversions"
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/object/acts_like"
+require_relative "core_ext/string/filters"
+require_relative "deprecation"
 
 module ActiveSupport
   # Provides accurate date and time measurements using Date#advance and
diff --git a/activesupport/lib/active_support/duration/iso8601_parser.rb b/activesupport/lib/active_support/duration/iso8601_parser.rb
index e96cb8e883..10f9e1fd0f 100644
--- a/activesupport/lib/active_support/duration/iso8601_parser.rb
+++ b/activesupport/lib/active_support/duration/iso8601_parser.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "strscan"
-require "active_support/core_ext/regexp"
+require_relative "../core_ext/regexp"
 
 module ActiveSupport
   class Duration
diff --git a/activesupport/lib/active_support/duration/iso8601_serializer.rb b/activesupport/lib/active_support/duration/iso8601_serializer.rb
index e5d458b3ab..829f935e3a 100644
--- a/activesupport/lib/active_support/duration/iso8601_serializer.rb
+++ b/activesupport/lib/active_support/duration/iso8601_serializer.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/object/blank"
-require "active_support/core_ext/hash/transform_values"
+# frozen_string_literal: true
+require_relative "../core_ext/object/blank"
+require_relative "../core_ext/hash/transform_values"
 
 module ActiveSupport
   class Duration
@@ -15,12 +16,12 @@ module ActiveSupport
         parts, sign = normalize
         return "PT0S".freeze if parts.empty?
 
-        output = "P"
+        output = "P".dup
         output << "#{parts[:years]}Y"   if parts.key?(:years)
         output << "#{parts[:months]}M"  if parts.key?(:months)
         output << "#{parts[:weeks]}W"   if parts.key?(:weeks)
         output << "#{parts[:days]}D"    if parts.key?(:days)
-        time = ""
+        time = "".dup
         time << "#{parts[:hours]}H"     if parts.key?(:hours)
         time << "#{parts[:minutes]}M"   if parts.key?(:minutes)
         if parts.key?(:seconds)
diff --git a/activesupport/lib/active_support/evented_file_update_checker.rb b/activesupport/lib/active_support/evented_file_update_checker.rb
index f59f5d17dc..3c456beac6 100644
--- a/activesupport/lib/active_support/evented_file_update_checker.rb
+++ b/activesupport/lib/active_support/evented_file_update_checker.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "set"
 require "pathname"
 require "concurrent/atomic/atomic_boolean"
diff --git a/activesupport/lib/active_support/execution_wrapper.rb b/activesupport/lib/active_support/execution_wrapper.rb
index ca88e7876b..189c06b811 100644
--- a/activesupport/lib/active_support/execution_wrapper.rb
+++ b/activesupport/lib/active_support/execution_wrapper.rb
@@ -1,4 +1,5 @@
-require "active_support/callbacks"
+# frozen_string_literal: true
+require_relative "callbacks"
 
 module ActiveSupport
   class ExecutionWrapper
diff --git a/activesupport/lib/active_support/executor.rb b/activesupport/lib/active_support/executor.rb
index a6400cae0a..2fd6325993 100644
--- a/activesupport/lib/active_support/executor.rb
+++ b/activesupport/lib/active_support/executor.rb
@@ -1,4 +1,5 @@
-require "active_support/execution_wrapper"
+# frozen_string_literal: true
+require_relative "execution_wrapper"
 
 module ActiveSupport
   class Executor < ExecutionWrapper
diff --git a/activesupport/lib/active_support/file_update_checker.rb b/activesupport/lib/active_support/file_update_checker.rb
index 2b5e3c1350..0201e86d1e 100644
--- a/activesupport/lib/active_support/file_update_checker.rb
+++ b/activesupport/lib/active_support/file_update_checker.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/time/calculations"
+# frozen_string_literal: true
+require_relative "core_ext/time/calculations"
 
 module ActiveSupport
   # FileUpdateChecker specifies the API used by Rails to watch files
diff --git a/activesupport/lib/active_support/gem_version.rb b/activesupport/lib/active_support/gem_version.rb
index 371a39a5e6..d6015b0161 100644
--- a/activesupport/lib/active_support/gem_version.rb
+++ b/activesupport/lib/active_support/gem_version.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # Returns the version of the currently loaded Active Support as a <tt>Gem::Version</tt>.
   def self.gem_version
diff --git a/activesupport/lib/active_support/gzip.rb b/activesupport/lib/active_support/gzip.rb
index 95a86889ec..fd9263500c 100644
--- a/activesupport/lib/active_support/gzip.rb
+++ b/activesupport/lib/active_support/gzip.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "zlib"
 require "stringio"
 
diff --git a/activesupport/lib/active_support/hash_with_indifferent_access.rb b/activesupport/lib/active_support/hash_with_indifferent_access.rb
index 3b185dd86b..6ede4559ba 100644
--- a/activesupport/lib/active_support/hash_with_indifferent_access.rb
+++ b/activesupport/lib/active_support/hash_with_indifferent_access.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/hash/keys"
-require "active_support/core_ext/hash/reverse_merge"
+# frozen_string_literal: true
+require_relative "core_ext/hash/keys"
+require_relative "core_ext/hash/reverse_merge"
 
 module ActiveSupport
   # Implements a hash where keys <tt>:foo</tt> and <tt>"foo"</tt> are considered
diff --git a/activesupport/lib/active_support/i18n.rb b/activesupport/lib/active_support/i18n.rb
index 1a1f1a1257..4548c89cbb 100644
--- a/activesupport/lib/active_support/i18n.rb
+++ b/activesupport/lib/active_support/i18n.rb
@@ -1,13 +1,14 @@
-require "active_support/core_ext/hash/deep_merge"
-require "active_support/core_ext/hash/except"
-require "active_support/core_ext/hash/slice"
+# frozen_string_literal: true
+require_relative "core_ext/hash/deep_merge"
+require_relative "core_ext/hash/except"
+require_relative "core_ext/hash/slice"
 begin
   require "i18n"
 rescue LoadError => e
   $stderr.puts "The i18n gem is not available. Please add it to your Gemfile and run bundle install"
   raise e
 end
-require "active_support/lazy_load_hooks"
+require_relative "lazy_load_hooks"
 
 ActiveSupport.run_load_hooks(:i18n)
 I18n.load_path << File.expand_path("locale/en.yml", __dir__)
diff --git a/activesupport/lib/active_support/i18n_railtie.rb b/activesupport/lib/active_support/i18n_railtie.rb
index 51fe6f3418..6a249e3906 100644
--- a/activesupport/lib/active_support/i18n_railtie.rb
+++ b/activesupport/lib/active_support/i18n_railtie.rb
@@ -1,6 +1,7 @@
+# frozen_string_literal: true
 require "active_support"
-require "active_support/file_update_checker"
-require "active_support/core_ext/array/wrap"
+require_relative "file_update_checker"
+require_relative "core_ext/array/wrap"
 
 # :enddoc:
 
diff --git a/activesupport/lib/active_support/inflections.rb b/activesupport/lib/active_support/inflections.rb
index afa7d1f325..339931b865 100644
--- a/activesupport/lib/active_support/inflections.rb
+++ b/activesupport/lib/active_support/inflections.rb
@@ -1,4 +1,5 @@
-require "active_support/inflector/inflections"
+# frozen_string_literal: true
+require_relative "inflector/inflections"
 
 #--
 # Defines the standard inflection rules. These are the starting point for
diff --git a/activesupport/lib/active_support/inflector.rb b/activesupport/lib/active_support/inflector.rb
index 48631b16a8..abfce1c17c 100644
--- a/activesupport/lib/active_support/inflector.rb
+++ b/activesupport/lib/active_support/inflector.rb
@@ -1,7 +1,8 @@
+# frozen_string_literal: true
 # in case active_support/inflector is required without the rest of active_support
-require "active_support/inflector/inflections"
-require "active_support/inflector/transliterate"
-require "active_support/inflector/methods"
+require_relative "inflector/inflections"
+require_relative "inflector/transliterate"
+require_relative "inflector/methods"
 
-require "active_support/inflections"
-require "active_support/core_ext/string/inflections"
+require_relative "inflections"
+require_relative "core_ext/string/inflections"
diff --git a/activesupport/lib/active_support/inflector/inflections.rb b/activesupport/lib/active_support/inflector/inflections.rb
index c47a2e34e1..b8f7cc4c6d 100644
--- a/activesupport/lib/active_support/inflector/inflections.rb
+++ b/activesupport/lib/active_support/inflector/inflections.rb
@@ -1,7 +1,8 @@
+# frozen_string_literal: true
 require "concurrent/map"
-require "active_support/core_ext/array/prepend_and_append"
-require "active_support/core_ext/regexp"
-require "active_support/i18n"
+require_relative "../core_ext/array/prepend_and_append"
+require_relative "../core_ext/regexp"
+require_relative "../i18n"
 
 module ActiveSupport
   module Inflector
diff --git a/activesupport/lib/active_support/inflector/methods.rb b/activesupport/lib/active_support/inflector/methods.rb
index ff1a0cb8c7..0e6fd145a2 100644
--- a/activesupport/lib/active_support/inflector/methods.rb
+++ b/activesupport/lib/active_support/inflector/methods.rb
@@ -1,5 +1,6 @@
-require "active_support/inflections"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../inflections"
+require_relative "../core_ext/regexp"
 
 module ActiveSupport
   # The Inflector transforms words from singular to plural, class names to table
diff --git a/activesupport/lib/active_support/inflector/transliterate.rb b/activesupport/lib/active_support/inflector/transliterate.rb
index de6dd2720b..6267142628 100644
--- a/activesupport/lib/active_support/inflector/transliterate.rb
+++ b/activesupport/lib/active_support/inflector/transliterate.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/string/multibyte"
-require "active_support/i18n"
+# frozen_string_literal: true
+require_relative "../core_ext/string/multibyte"
+require_relative "../i18n"
 
 module ActiveSupport
   module Inflector
diff --git a/activesupport/lib/active_support/json.rb b/activesupport/lib/active_support/json.rb
index da938d1555..043750e05c 100644
--- a/activesupport/lib/active_support/json.rb
+++ b/activesupport/lib/active_support/json.rb
@@ -1,2 +1,3 @@
-require "active_support/json/decoding"
-require "active_support/json/encoding"
+# frozen_string_literal: true
+require_relative "json/decoding"
+require_relative "json/encoding"
diff --git a/activesupport/lib/active_support/json/decoding.rb b/activesupport/lib/active_support/json/decoding.rb
index f487fa0c65..515a11edf1 100644
--- a/activesupport/lib/active_support/json/decoding.rb
+++ b/activesupport/lib/active_support/json/decoding.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/module/delegation"
+# frozen_string_literal: true
+require_relative "../core_ext/module/attribute_accessors"
+require_relative "../core_ext/module/delegation"
 require "json"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/json/encoding.rb b/activesupport/lib/active_support/json/encoding.rb
index defaf3f395..153f1fdbd2 100644
--- a/activesupport/lib/active_support/json/encoding.rb
+++ b/activesupport/lib/active_support/json/encoding.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/object/json"
-require "active_support/core_ext/module/delegation"
+# frozen_string_literal: true
+require_relative "../core_ext/object/json"
+require_relative "../core_ext/module/delegation"
 
 module ActiveSupport
   class << self
diff --git a/activesupport/lib/active_support/key_generator.rb b/activesupport/lib/active_support/key_generator.rb
index 23ab804eb1..a0b2a70ee3 100644
--- a/activesupport/lib/active_support/key_generator.rb
+++ b/activesupport/lib/active_support/key_generator.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "concurrent/map"
 require "openssl"
 
diff --git a/activesupport/lib/active_support/lazy_load_hooks.rb b/activesupport/lib/active_support/lazy_load_hooks.rb
index 720ed47331..b1fc6b331b 100644
--- a/activesupport/lib/active_support/lazy_load_hooks.rb
+++ b/activesupport/lib/active_support/lazy_load_hooks.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # lazy_load_hooks allows Rails to lazily load a lot of components and thus
   # making the app boot faster. Because of this feature now there is no need to
diff --git a/activesupport/lib/active_support/log_subscriber.rb b/activesupport/lib/active_support/log_subscriber.rb
index e2c4f33565..a5b502a30e 100644
--- a/activesupport/lib/active_support/log_subscriber.rb
+++ b/activesupport/lib/active_support/log_subscriber.rb
@@ -1,6 +1,7 @@
-require "active_support/core_ext/module/attribute_accessors"
-require "active_support/core_ext/class/attribute"
-require "active_support/subscriber"
+# frozen_string_literal: true
+require_relative "core_ext/module/attribute_accessors"
+require_relative "core_ext/class/attribute"
+require_relative "subscriber"
 
 module ActiveSupport
   # ActiveSupport::LogSubscriber is an object set to consume
@@ -49,8 +50,7 @@ module ActiveSupport
     CYAN    = "\e[36m"
     WHITE   = "\e[37m"
 
-    mattr_accessor :colorize_logging
-    self.colorize_logging = true
+    mattr_accessor :colorize_logging, default: true
 
     class << self
       def logger
@@ -81,8 +81,10 @@ module ActiveSupport
 
     def finish(name, id, payload)
       super if logger
-    rescue Exception => e
-      logger.error "Could not log #{name.inspect} event. #{e.class}: #{e.message} #{e.backtrace}"
+    rescue => e
+      if logger
+        logger.error "Could not log #{name.inspect} event. #{e.class}: #{e.message} #{e.backtrace}"
+      end
     end
 
   private
diff --git a/activesupport/lib/active_support/log_subscriber/test_helper.rb b/activesupport/lib/active_support/log_subscriber/test_helper.rb
index 953ee77c2a..7f25d6b0b3 100644
--- a/activesupport/lib/active_support/log_subscriber/test_helper.rb
+++ b/activesupport/lib/active_support/log_subscriber/test_helper.rb
@@ -1,6 +1,7 @@
-require "active_support/log_subscriber"
-require "active_support/logger"
-require "active_support/notifications"
+# frozen_string_literal: true
+require_relative "../log_subscriber"
+require_relative "../logger"
+require_relative "../notifications"
 
 module ActiveSupport
   class LogSubscriber
diff --git a/activesupport/lib/active_support/logger.rb b/activesupport/lib/active_support/logger.rb
index ea09d7d2df..2bbff5892d 100644
--- a/activesupport/lib/active_support/logger.rb
+++ b/activesupport/lib/active_support/logger.rb
@@ -1,5 +1,6 @@
-require "active_support/logger_silence"
-require "active_support/logger_thread_safe_level"
+# frozen_string_literal: true
+require_relative "logger_silence"
+require_relative "logger_thread_safe_level"
 require "logger"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/logger_silence.rb b/activesupport/lib/active_support/logger_silence.rb
index 632994cf50..5c8d4dba5e 100644
--- a/activesupport/lib/active_support/logger_silence.rb
+++ b/activesupport/lib/active_support/logger_silence.rb
@@ -1,13 +1,13 @@
-require "active_support/concern"
-require "active_support/core_ext/module/attribute_accessors"
+# frozen_string_literal: true
+require_relative "concern"
+require_relative "core_ext/module/attribute_accessors"
 require "concurrent"
 
 module LoggerSilence
   extend ActiveSupport::Concern
 
   included do
-    cattr_accessor :silencer
-    self.silencer = true
+    cattr_accessor :silencer, default: true
   end
 
   # Silences the logger for the duration of the block.
diff --git a/activesupport/lib/active_support/logger_thread_safe_level.rb b/activesupport/lib/active_support/logger_thread_safe_level.rb
index 7fb175dea6..4b5f2e7fb3 100644
--- a/activesupport/lib/active_support/logger_thread_safe_level.rb
+++ b/activesupport/lib/active_support/logger_thread_safe_level.rb
@@ -1,4 +1,5 @@
-require "active_support/concern"
+# frozen_string_literal: true
+require_relative "concern"
 
 module ActiveSupport
   module LoggerThreadSafeLevel # :nodoc:
diff --git a/activesupport/lib/active_support/message_encryptor.rb b/activesupport/lib/active_support/message_encryptor.rb
index 726e1464ad..03e7d5b436 100644
--- a/activesupport/lib/active_support/message_encryptor.rb
+++ b/activesupport/lib/active_support/message_encryptor.rb
@@ -1,7 +1,8 @@
+# frozen_string_literal: true
 require "openssl"
 require "base64"
-require "active_support/core_ext/array/extract_options"
-require "active_support/message_verifier"
+require_relative "core_ext/array/extract_options"
+require_relative "message_verifier"
 
 module ActiveSupport
   # MessageEncryptor is a simple way to encrypt values which get stored
@@ -13,13 +14,24 @@ module ActiveSupport
   # This can be used in situations similar to the <tt>MessageVerifier</tt>, but
   # where you don't want users to be able to determine the value of the payload.
   #
-  #   salt  = SecureRandom.random_bytes(64)
-  #   key   = ActiveSupport::KeyGenerator.new('password').generate_key(salt, 32) # => "\x89\xE0\x156\xAC..."
-  #   crypt = ActiveSupport::MessageEncryptor.new(key)                           # => #<ActiveSupport::MessageEncryptor ...>
-  #   encrypted_data = crypt.encrypt_and_sign('my secret data')                  # => "NlFBTTMwOUV5UlA1QlNEN2xkY2d6eThYWWh..."
-  #   crypt.decrypt_and_verify(encrypted_data)                                   # => "my secret data"
+  #   len   = ActiveSupport::MessageEncryptor.key_len
+  #   salt  = SecureRandom.random_bytes(len)
+  #   key   = ActiveSupport::KeyGenerator.new('password').generate_key(salt, len) # => "\x89\xE0\x156\xAC..."
+  #   crypt = ActiveSupport::MessageEncryptor.new(key)                            # => #<ActiveSupport::MessageEncryptor ...>
+  #   encrypted_data = crypt.encrypt_and_sign('my secret data')                   # => "NlFBTTMwOUV5UlA1QlNEN2xkY2d6eThYWWh..."
+  #   crypt.decrypt_and_verify(encrypted_data)                                    # => "my secret data"
   class MessageEncryptor
-    DEFAULT_CIPHER = "aes-256-cbc"
+    class << self
+      attr_accessor :use_authenticated_message_encryption #:nodoc:
+
+      def default_cipher #:nodoc:
+        if use_authenticated_message_encryption
+          "aes-256-gcm"
+        else
+          "aes-256-cbc"
+        end
+      end
+    end
 
     module NullSerializer #:nodoc:
       def self.load(value)
@@ -45,7 +57,7 @@ module ActiveSupport
     OpenSSLCipherError = OpenSSL::Cipher::CipherError
 
     # Initialize a new MessageEncryptor. +secret+ must be at least as long as
-    # the cipher key size. For the default 'aes-256-cbc' cipher, this is 256
+    # the cipher key size. For the default 'aes-256-gcm' cipher, this is 256
     # bits. If you are using a user-entered secret, you can generate a suitable
     # key by using <tt>ActiveSupport::KeyGenerator</tt> or a similar key
     # derivation function.
@@ -57,7 +69,7 @@ module ActiveSupport
     #
     # Options:
     # * <tt>:cipher</tt>     - Cipher to use. Can be any cipher returned by
-    #   <tt>OpenSSL::Cipher.ciphers</tt>. Default is 'aes-256-cbc'.
+    #   <tt>OpenSSL::Cipher.ciphers</tt>. Default is 'aes-256-gcm'.
     # * <tt>:digest</tt> - String of digest to use for signing. Default is
     #   +SHA1+. Ignored when using an AEAD cipher like 'aes-256-gcm'.
     # * <tt>:serializer</tt> - Object serializer to use. Default is +Marshal+.
@@ -66,7 +78,7 @@ module ActiveSupport
       sign_secret = signature_key_or_options.first
       @secret = secret
       @sign_secret = sign_secret
-      @cipher = options[:cipher] || DEFAULT_CIPHER
+      @cipher = options[:cipher] || self.class.default_cipher
       @digest = options[:digest] || "SHA1" unless aead_mode?
       @verifier = resolve_verifier
       @serializer = options[:serializer] || Marshal
@@ -85,7 +97,7 @@ module ActiveSupport
     end
 
     # Given a cipher, returns the key length of the cipher to help generate the key of desired size
-    def self.key_len(cipher = DEFAULT_CIPHER)
+    def self.key_len(cipher = default_cipher)
       OpenSSL::Cipher.new(cipher).key_len
     end
 
@@ -104,7 +116,7 @@ module ActiveSupport
         encrypted_data << cipher.final
 
         blob = "#{::Base64.strict_encode64 encrypted_data}--#{::Base64.strict_encode64 iv}"
-        blob << "--#{::Base64.strict_encode64 cipher.auth_tag}" if aead_mode?
+        blob = "#{blob}--#{::Base64.strict_encode64 cipher.auth_tag}" if aead_mode?
         blob
       end
 
diff --git a/activesupport/lib/active_support/message_verifier.rb b/activesupport/lib/active_support/message_verifier.rb
index 8419e858c6..2eb09e41e0 100644
--- a/activesupport/lib/active_support/message_verifier.rb
+++ b/activesupport/lib/active_support/message_verifier.rb
@@ -1,6 +1,7 @@
+# frozen_string_literal: true
 require "base64"
-require "active_support/core_ext/object/blank"
-require "active_support/security_utils"
+require_relative "core_ext/object/blank"
+require_relative "security_utils"
 
 module ActiveSupport
   # +MessageVerifier+ makes it easy to generate and verify messages which are
diff --git a/activesupport/lib/active_support/multibyte.rb b/activesupport/lib/active_support/multibyte.rb
index f7c7befee0..0a3418ae95 100644
--- a/activesupport/lib/active_support/multibyte.rb
+++ b/activesupport/lib/active_support/multibyte.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport #:nodoc:
   module Multibyte
     autoload :Chars, "active_support/multibyte/chars"
diff --git a/activesupport/lib/active_support/multibyte/chars.rb b/activesupport/lib/active_support/multibyte/chars.rb
index 8c58466556..7bd1200fa6 100644
--- a/activesupport/lib/active_support/multibyte/chars.rb
+++ b/activesupport/lib/active_support/multibyte/chars.rb
@@ -1,8 +1,9 @@
-require "active_support/json"
-require "active_support/core_ext/string/access"
-require "active_support/core_ext/string/behavior"
-require "active_support/core_ext/module/delegation"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../json"
+require_relative "../core_ext/string/access"
+require_relative "../core_ext/string/behavior"
+require_relative "../core_ext/module/delegation"
+require_relative "../core_ext/regexp"
 
 module ActiveSupport #:nodoc:
   module Multibyte #:nodoc:
diff --git a/activesupport/lib/active_support/multibyte/unicode.rb b/activesupport/lib/active_support/multibyte/unicode.rb
index 8223e45e5a..92575b1c9b 100644
--- a/activesupport/lib/active_support/multibyte/unicode.rb
+++ b/activesupport/lib/active_support/multibyte/unicode.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Multibyte
     module Unicode
diff --git a/activesupport/lib/active_support/notifications.rb b/activesupport/lib/active_support/notifications.rb
index 37dfdc0422..88ba85d8c7 100644
--- a/activesupport/lib/active_support/notifications.rb
+++ b/activesupport/lib/active_support/notifications.rb
@@ -1,6 +1,7 @@
-require "active_support/notifications/instrumenter"
-require "active_support/notifications/fanout"
-require "active_support/per_thread_registry"
+# frozen_string_literal: true
+require_relative "notifications/instrumenter"
+require_relative "notifications/fanout"
+require_relative "per_thread_registry"
 
 module ActiveSupport
   # = Notifications
diff --git a/activesupport/lib/active_support/notifications/fanout.rb b/activesupport/lib/active_support/notifications/fanout.rb
index 9da115f552..b69d1bcd25 100644
--- a/activesupport/lib/active_support/notifications/fanout.rb
+++ b/activesupport/lib/active_support/notifications/fanout.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "mutex_m"
 require "concurrent/map"
 
diff --git a/activesupport/lib/active_support/notifications/instrumenter.rb b/activesupport/lib/active_support/notifications/instrumenter.rb
index e11e2e0689..00936f5b9e 100644
--- a/activesupport/lib/active_support/notifications/instrumenter.rb
+++ b/activesupport/lib/active_support/notifications/instrumenter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "securerandom"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/number_helper.rb b/activesupport/lib/active_support/number_helper.rb
index 9cb2821cb6..965664eb65 100644
--- a/activesupport/lib/active_support/number_helper.rb
+++ b/activesupport/lib/active_support/number_helper.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     extend ActiveSupport::Autoload
diff --git a/activesupport/lib/active_support/number_helper/number_converter.rb b/activesupport/lib/active_support/number_helper/number_converter.rb
index ce363287cf..d2be18ce27 100644
--- a/activesupport/lib/active_support/number_helper/number_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_converter.rb
@@ -1,8 +1,9 @@
-require "active_support/core_ext/big_decimal/conversions"
-require "active_support/core_ext/object/blank"
-require "active_support/core_ext/hash/keys"
-require "active_support/i18n"
-require "active_support/core_ext/class/attribute"
+# frozen_string_literal: true
+require_relative "../core_ext/big_decimal/conversions"
+require_relative "../core_ext/object/blank"
+require_relative "../core_ext/hash/keys"
+require_relative "../i18n"
+require_relative "../core_ext/class/attribute"
 
 module ActiveSupport
   module NumberHelper
diff --git a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
index 0f9dce722f..c260b5b126 100644
--- a/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_currency_converter.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/numeric/inquiry"
+# frozen_string_literal: true
+require_relative "../core_ext/numeric/inquiry"
 
 module ActiveSupport
   module NumberHelper
diff --git a/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
index e3b35531b1..620e6b4282 100644
--- a/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_delimited_converter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToDelimitedConverter < NumberConverter #:nodoc:
diff --git a/activesupport/lib/active_support/number_helper/number_to_human_converter.rb b/activesupport/lib/active_support/number_helper/number_to_human_converter.rb
index 040343b5dd..852a76fbb6 100644
--- a/activesupport/lib/active_support/number_helper/number_to_human_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_human_converter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToHumanConverter < NumberConverter # :nodoc:
diff --git a/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
index f263dbe9f8..a1ebb92fe7 100644
--- a/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_human_size_converter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToHumanSizeConverter < NumberConverter #:nodoc:
diff --git a/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb b/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb
index ac647ca9b7..9285d7d93f 100644
--- a/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_percentage_converter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToPercentageConverter < NumberConverter # :nodoc:
diff --git a/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb b/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb
index 1de9f50f34..e1f2fec55b 100644
--- a/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_phone_converter.rb
@@ -1,8 +1,9 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToPhoneConverter < NumberConverter #:nodoc:
       def convert
-        str = country_code(opts[:country_code])
+        str = country_code(opts[:country_code]).dup
         str << convert_to_phone_number(number.to_s.strip)
         str << phone_ext(opts[:extension])
       end
diff --git a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
index c32d85a45f..6e8b5ee653 100644
--- a/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
+++ b/activesupport/lib/active_support/number_helper/number_to_rounded_converter.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class NumberToRoundedConverter < NumberConverter # :nodoc:
diff --git a/activesupport/lib/active_support/number_helper/rounding_helper.rb b/activesupport/lib/active_support/number_helper/rounding_helper.rb
index d9644df17d..f5d5f4664b 100644
--- a/activesupport/lib/active_support/number_helper/rounding_helper.rb
+++ b/activesupport/lib/active_support/number_helper/rounding_helper.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module NumberHelper
     class RoundingHelper # :nodoc:
@@ -40,11 +41,11 @@ module ActiveSupport
         def convert_to_decimal(number)
           case number
           when Float, String
-            number = BigDecimal(number.to_s)
+            BigDecimal(number.to_s)
           when Rational
-            number = BigDecimal(number, digit_count(number.to_i) + precision)
+            BigDecimal(number, digit_count(number.to_i) + precision)
           else
-            number = number.to_d
+            number.to_d
           end
         end
 
diff --git a/activesupport/lib/active_support/option_merger.rb b/activesupport/lib/active_support/option_merger.rb
index 0f2caa98f2..5788332349 100644
--- a/activesupport/lib/active_support/option_merger.rb
+++ b/activesupport/lib/active_support/option_merger.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/hash/deep_merge"
+# frozen_string_literal: true
+require_relative "core_ext/hash/deep_merge"
 
 module ActiveSupport
   class OptionMerger #:nodoc:
diff --git a/activesupport/lib/active_support/ordered_hash.rb b/activesupport/lib/active_support/ordered_hash.rb
index 3aa0a14f04..b07b89447e 100644
--- a/activesupport/lib/active_support/ordered_hash.rb
+++ b/activesupport/lib/active_support/ordered_hash.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "yaml"
 
 YAML.add_builtin_type("omap") do |type, val|
diff --git a/activesupport/lib/active_support/ordered_options.rb b/activesupport/lib/active_support/ordered_options.rb
index 04d6dfaf9c..457418a79a 100644
--- a/activesupport/lib/active_support/ordered_options.rb
+++ b/activesupport/lib/active_support/ordered_options.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/object/blank"
+# frozen_string_literal: true
+require_relative "core_ext/object/blank"
 
 module ActiveSupport
   # Usually key value pairs are handled something like this:
diff --git a/activesupport/lib/active_support/per_thread_registry.rb b/activesupport/lib/active_support/per_thread_registry.rb
index 02431704d3..662c88d17d 100644
--- a/activesupport/lib/active_support/per_thread_registry.rb
+++ b/activesupport/lib/active_support/per_thread_registry.rb
@@ -1,4 +1,5 @@
-require "active_support/core_ext/module/delegation"
+# frozen_string_literal: true
+require_relative "core_ext/module/delegation"
 
 module ActiveSupport
   # NOTE: This approach has been deprecated for end-user code in favor of {thread_mattr_accessor}[rdoc-ref:Module#thread_mattr_accessor] and friends.
diff --git a/activesupport/lib/active_support/proxy_object.rb b/activesupport/lib/active_support/proxy_object.rb
index 20a0fd8e62..df84ab6225 100644
--- a/activesupport/lib/active_support/proxy_object.rb
+++ b/activesupport/lib/active_support/proxy_object.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # A class with no predefined methods that behaves similarly to Builder's
   # BlankSlate. Used for proxy classes.
diff --git a/activesupport/lib/active_support/rails.rb b/activesupport/lib/active_support/rails.rb
index f6b018f0d3..c4fae94d5e 100644
--- a/activesupport/lib/active_support/rails.rb
+++ b/activesupport/lib/active_support/rails.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 # This is private interface.
 #
 # Rails components cherry pick from Active Support as needed, but there are a
@@ -9,25 +10,25 @@
 # Rails and can change anytime.
 
 # Defines Object#blank? and Object#present?.
-require "active_support/core_ext/object/blank"
+require_relative "core_ext/object/blank"
 
 # Rails own autoload, eager_load, etc.
-require "active_support/dependencies/autoload"
+require_relative "dependencies/autoload"
 
 # Support for ClassMethods and the included macro.
-require "active_support/concern"
+require_relative "concern"
 
 # Defines Class#class_attribute.
-require "active_support/core_ext/class/attribute"
+require_relative "core_ext/class/attribute"
 
 # Defines Module#delegate.
-require "active_support/core_ext/module/delegation"
+require_relative "core_ext/module/delegation"
 
 # Defines ActiveSupport::Deprecation.
-require "active_support/deprecation"
+require_relative "deprecation"
 
 # Defines Regexp#match?.
 #
 # This should be removed when Rails needs Ruby 2.4 or later, and the require
 # added where other Regexp extensions are being used (easy to grep).
-require "active_support/core_ext/regexp"
+require_relative "core_ext/regexp"
diff --git a/activesupport/lib/active_support/railtie.rb b/activesupport/lib/active_support/railtie.rb
index 1b4ecf4d72..7903d229c0 100644
--- a/activesupport/lib/active_support/railtie.rb
+++ b/activesupport/lib/active_support/railtie.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "active_support"
-require "active_support/i18n_railtie"
+require_relative "i18n_railtie"
 
 module ActiveSupport
   class Railtie < Rails::Railtie # :nodoc:
@@ -7,6 +8,13 @@ module ActiveSupport
 
     config.eager_load_namespaces << ActiveSupport
 
+    initializer "active_support.set_authenticated_message_encryption" do |app|
+      if app.config.active_support.respond_to?(:use_authenticated_message_encryption)
+        ActiveSupport::MessageEncryptor.use_authenticated_message_encryption =
+          app.config.active_support.use_authenticated_message_encryption
+      end
+    end
+
     initializer "active_support.reset_all_current_attributes_instances" do |app|
       app.reloader.before_class_unload { ActiveSupport::CurrentAttributes.clear_all }
       app.executor.to_run              { ActiveSupport::CurrentAttributes.reset_all }
@@ -27,21 +35,14 @@ module ActiveSupport
       rescue TZInfo::DataSourceNotFound => e
         raise e.exception "tzinfo-data is not present. Please add gem 'tzinfo-data' to your Gemfile and run bundle install"
       end
-      require "active_support/core_ext/time/zones"
-      zone_default = Time.find_zone!(app.config.time_zone)
-
-      unless zone_default
-        raise "Value assigned to config.time_zone not recognized. " \
-          'Run "rake time:zones:all" for a time zone names list.'
-      end
-
-      Time.zone_default = zone_default
+      require_relative "core_ext/time/zones"
+      Time.zone_default = Time.find_zone!(app.config.time_zone)
     end
 
     # Sets the default week start
     # If assigned value is not a valid day symbol (e.g. :sunday, :monday, ...), an exception will be raised.
     initializer "active_support.initialize_beginning_of_week" do |app|
-      require "active_support/core_ext/date/calculations"
+      require_relative "core_ext/date/calculations"
       beginning_of_week_default = Date.find_beginning_of_week!(app.config.beginning_of_week)
 
       Date.beginning_of_week_default = beginning_of_week_default
diff --git a/activesupport/lib/active_support/reloader.rb b/activesupport/lib/active_support/reloader.rb
index 9558146201..6e81c95961 100644
--- a/activesupport/lib/active_support/reloader.rb
+++ b/activesupport/lib/active_support/reloader.rb
@@ -1,4 +1,5 @@
-require "active_support/execution_wrapper"
+# frozen_string_literal: true
+require_relative "execution_wrapper"
 
 module ActiveSupport
   #--
diff --git a/activesupport/lib/active_support/rescuable.rb b/activesupport/lib/active_support/rescuable.rb
index 826832ba7d..db736f5c23 100644
--- a/activesupport/lib/active_support/rescuable.rb
+++ b/activesupport/lib/active_support/rescuable.rb
@@ -1,6 +1,7 @@
-require "active_support/concern"
-require "active_support/core_ext/class/attribute"
-require "active_support/core_ext/string/inflections"
+# frozen_string_literal: true
+require_relative "concern"
+require_relative "core_ext/class/attribute"
+require_relative "core_ext/string/inflections"
 
 module ActiveSupport
   # Rescuable module adds support for easier exception handling.
diff --git a/activesupport/lib/active_support/security_utils.rb b/activesupport/lib/active_support/security_utils.rb
index b655d64449..2e61a72213 100644
--- a/activesupport/lib/active_support/security_utils.rb
+++ b/activesupport/lib/active_support/security_utils.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "digest"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/string_inquirer.rb b/activesupport/lib/active_support/string_inquirer.rb
index 90eac89c9e..03bcbb2555 100644
--- a/activesupport/lib/active_support/string_inquirer.rb
+++ b/activesupport/lib/active_support/string_inquirer.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   # Wrapping a string in this class gives you a prettier way to test
   # for equality. The value returned by <tt>Rails.env</tt> is wrapped
diff --git a/activesupport/lib/active_support/subscriber.rb b/activesupport/lib/active_support/subscriber.rb
index 2924139755..23268e990a 100644
--- a/activesupport/lib/active_support/subscriber.rb
+++ b/activesupport/lib/active_support/subscriber.rb
@@ -1,5 +1,6 @@
-require "active_support/per_thread_registry"
-require "active_support/notifications"
+# frozen_string_literal: true
+require_relative "per_thread_registry"
+require_relative "notifications"
 
 module ActiveSupport
   # ActiveSupport::Subscriber is an object set to consume
diff --git a/activesupport/lib/active_support/tagged_logging.rb b/activesupport/lib/active_support/tagged_logging.rb
index ad134c49b6..7c06c0579f 100644
--- a/activesupport/lib/active_support/tagged_logging.rb
+++ b/activesupport/lib/active_support/tagged_logging.rb
@@ -1,7 +1,8 @@
-require "active_support/core_ext/module/delegation"
-require "active_support/core_ext/object/blank"
+# frozen_string_literal: true
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/object/blank"
 require "logger"
-require "active_support/logger"
+require_relative "logger"
 
 module ActiveSupport
   # Wraps any standard Logger object to provide tagging capabilities.
diff --git a/activesupport/lib/active_support/test_case.rb b/activesupport/lib/active_support/test_case.rb
index 3de4ccc1da..df2d3002c9 100644
--- a/activesupport/lib/active_support/test_case.rb
+++ b/activesupport/lib/active_support/test_case.rb
@@ -1,15 +1,16 @@
+# frozen_string_literal: true
 gem "minitest" # make sure we get the gem, not stdlib
 require "minitest"
-require "active_support/testing/tagged_logging"
-require "active_support/testing/setup_and_teardown"
-require "active_support/testing/assertions"
-require "active_support/testing/deprecation"
-require "active_support/testing/declarative"
-require "active_support/testing/isolation"
-require "active_support/testing/constant_lookup"
-require "active_support/testing/time_helpers"
-require "active_support/testing/file_fixtures"
-require "active_support/core_ext/kernel/reporting"
+require_relative "testing/tagged_logging"
+require_relative "testing/setup_and_teardown"
+require_relative "testing/assertions"
+require_relative "testing/deprecation"
+require_relative "testing/declarative"
+require_relative "testing/isolation"
+require_relative "testing/constant_lookup"
+require_relative "testing/time_helpers"
+require_relative "testing/file_fixtures"
+require_relative "core_ext/kernel/reporting"
 
 module ActiveSupport
   class TestCase < ::Minitest::Test
diff --git a/activesupport/lib/active_support/testing/assertions.rb b/activesupport/lib/active_support/testing/assertions.rb
index 28e1df8870..d7bb5e5bdf 100644
--- a/activesupport/lib/active_support/testing/assertions.rb
+++ b/activesupport/lib/active_support/testing/assertions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     module Assertions
diff --git a/activesupport/lib/active_support/testing/autorun.rb b/activesupport/lib/active_support/testing/autorun.rb
index a18788f38e..40ae696a34 100644
--- a/activesupport/lib/active_support/testing/autorun.rb
+++ b/activesupport/lib/active_support/testing/autorun.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 gem "minitest"
 
 require "minitest"
diff --git a/activesupport/lib/active_support/testing/constant_lookup.rb b/activesupport/lib/active_support/testing/constant_lookup.rb
index 647395d2b3..a231697979 100644
--- a/activesupport/lib/active_support/testing/constant_lookup.rb
+++ b/activesupport/lib/active_support/testing/constant_lookup.rb
@@ -1,5 +1,6 @@
-require "active_support/concern"
-require "active_support/inflector"
+# frozen_string_literal: true
+require_relative "../concern"
+require_relative "../inflector"
 
 module ActiveSupport
   module Testing
diff --git a/activesupport/lib/active_support/testing/declarative.rb b/activesupport/lib/active_support/testing/declarative.rb
index 53ab3ebf78..601f6fb16d 100644
--- a/activesupport/lib/active_support/testing/declarative.rb
+++ b/activesupport/lib/active_support/testing/declarative.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     module Declarative
diff --git a/activesupport/lib/active_support/testing/deprecation.rb b/activesupport/lib/active_support/testing/deprecation.rb
index 58911570e8..1145afceff 100644
--- a/activesupport/lib/active_support/testing/deprecation.rb
+++ b/activesupport/lib/active_support/testing/deprecation.rb
@@ -1,5 +1,6 @@
-require "active_support/deprecation"
-require "active_support/core_ext/regexp"
+# frozen_string_literal: true
+require_relative "../deprecation"
+require_relative "../core_ext/regexp"
 
 module ActiveSupport
   module Testing
diff --git a/activesupport/lib/active_support/testing/file_fixtures.rb b/activesupport/lib/active_support/testing/file_fixtures.rb
index affb84cda5..56f80fb547 100644
--- a/activesupport/lib/active_support/testing/file_fixtures.rb
+++ b/activesupport/lib/active_support/testing/file_fixtures.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     # Adds simple access to sample files called file fixtures.
diff --git a/activesupport/lib/active_support/testing/isolation.rb b/activesupport/lib/active_support/testing/isolation.rb
index 54c3263efa..4d43c06085 100644
--- a/activesupport/lib/active_support/testing/isolation.rb
+++ b/activesupport/lib/active_support/testing/isolation.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     module Isolation
diff --git a/activesupport/lib/active_support/testing/method_call_assertions.rb b/activesupport/lib/active_support/testing/method_call_assertions.rb
index 6b07416fdc..d33224e9c3 100644
--- a/activesupport/lib/active_support/testing/method_call_assertions.rb
+++ b/activesupport/lib/active_support/testing/method_call_assertions.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "minitest/mock"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/testing/setup_and_teardown.rb b/activesupport/lib/active_support/testing/setup_and_teardown.rb
index 358c79c321..e80b8d17ef 100644
--- a/activesupport/lib/active_support/testing/setup_and_teardown.rb
+++ b/activesupport/lib/active_support/testing/setup_and_teardown.rb
@@ -1,5 +1,6 @@
-require "active_support/concern"
-require "active_support/callbacks"
+# frozen_string_literal: true
+require_relative "../concern"
+require_relative "../callbacks"
 
 module ActiveSupport
   module Testing
diff --git a/activesupport/lib/active_support/testing/stream.rb b/activesupport/lib/active_support/testing/stream.rb
index 1d06b94559..4e8303f058 100644
--- a/activesupport/lib/active_support/testing/stream.rb
+++ b/activesupport/lib/active_support/testing/stream.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     module Stream #:nodoc:
diff --git a/activesupport/lib/active_support/testing/tagged_logging.rb b/activesupport/lib/active_support/testing/tagged_logging.rb
index afdff87b45..3ca45b4ab5 100644
--- a/activesupport/lib/active_support/testing/tagged_logging.rb
+++ b/activesupport/lib/active_support/testing/tagged_logging.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   module Testing
     # Logs a "PostsControllerTest: test name" heading before each test to
diff --git a/activesupport/lib/active_support/testing/time_helpers.rb b/activesupport/lib/active_support/testing/time_helpers.rb
index 3d9ff99729..d72d82d7c4 100644
--- a/activesupport/lib/active_support/testing/time_helpers.rb
+++ b/activesupport/lib/active_support/testing/time_helpers.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/string/strip" # for strip_heredoc
-require "active_support/core_ext/time/calculations"
+# frozen_string_literal: true
+require_relative "../core_ext/string/strip" # for strip_heredoc
+require_relative "../core_ext/time/calculations"
 require "concurrent/map"
 
 module ActiveSupport
@@ -160,6 +161,27 @@ module ActiveSupport
         simple_stubs.unstub_all!
       end
 
+      # Calls `travel_to` with `Time.now`.
+      #
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   freeze_time
+      #   sleep(1)
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #
+      # This method also accepts a block, which will return the current time back to its original
+      # state at the end of the block:
+      #
+      #   Time.current # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   freeze_time do
+      #     sleep(1)
+      #     User.create.created_at # => Sun, 09 Jul 2017 15:34:49 EST -05:00
+      #   end
+      #   Time.current # => Sun, 09 Jul 2017 15:34:50 EST -05:00
+
+      def freeze_time(&block)
+        travel_to Time.now, &block
+      end
+
       private
 
         def simple_stubs
diff --git a/activesupport/lib/active_support/time.rb b/activesupport/lib/active_support/time.rb
index 7658228ca6..6004119717 100644
--- a/activesupport/lib/active_support/time.rb
+++ b/activesupport/lib/active_support/time.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ActiveSupport
   autoload :Duration, "active_support/duration"
   autoload :TimeWithZone, "active_support/time_with_zone"
@@ -7,12 +8,12 @@ end
 require "date"
 require "time"
 
-require "active_support/core_ext/time"
-require "active_support/core_ext/date"
-require "active_support/core_ext/date_time"
+require_relative "core_ext/time"
+require_relative "core_ext/date"
+require_relative "core_ext/date_time"
 
-require "active_support/core_ext/integer/time"
-require "active_support/core_ext/numeric/time"
+require_relative "core_ext/integer/time"
+require_relative "core_ext/numeric/time"
 
-require "active_support/core_ext/string/conversions"
-require "active_support/core_ext/string/zones"
+require_relative "core_ext/string/conversions"
+require_relative "core_ext/string/zones"
diff --git a/activesupport/lib/active_support/time_with_zone.rb b/activesupport/lib/active_support/time_with_zone.rb
index ecb9fb6785..444a714d53 100644
--- a/activesupport/lib/active_support/time_with_zone.rb
+++ b/activesupport/lib/active_support/time_with_zone.rb
@@ -1,7 +1,8 @@
-require "active_support/duration"
-require "active_support/values/time_zone"
-require "active_support/core_ext/object/acts_like"
-require "active_support/core_ext/date_and_time/compatibility"
+# frozen_string_literal: true
+require_relative "duration"
+require_relative "values/time_zone"
+require_relative "core_ext/object/acts_like"
+require_relative "core_ext/date_and_time/compatibility"
 
 module ActiveSupport
   # A Time-like class that can represent a time in any time zone. Necessary
diff --git a/activesupport/lib/active_support/values/time_zone.rb b/activesupport/lib/active_support/values/time_zone.rb
index 96a541a4ef..632f70f93c 100644
--- a/activesupport/lib/active_support/values/time_zone.rb
+++ b/activesupport/lib/active_support/values/time_zone.rb
@@ -1,6 +1,7 @@
+# frozen_string_literal: true
 require "tzinfo"
 require "concurrent/map"
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 
 module ActiveSupport
   # The TimeZone class serves as a wrapper around TZInfo::Timezone instances.
@@ -359,7 +360,7 @@ module ActiveSupport
     #   Time.zone.iso8601('1999-12-31') # => Fri, 31 Dec 1999 00:00:00 HST -10:00
     #
     # If the string is invalid then an +ArgumentError+ will be raised unlike +parse+
-    # which returns +nil+ when given an invalid date string.
+    # which usually returns +nil+ when given an invalid date string.
     def iso8601(str)
       parts = Date._iso8601(str)
 
@@ -398,6 +399,8 @@ module ActiveSupport
     # components are supplied, then the day of the month defaults to 1:
     #
     #   Time.zone.parse('Mar 2000') # => Wed, 01 Mar 2000 00:00:00 HST -10:00
+    #
+    # If the string is invalid then an +ArgumentError+ could be raised.
     def parse(str, now = now())
       parts_to_time(Date._parse(str, false), now)
     end
diff --git a/activesupport/lib/active_support/version.rb b/activesupport/lib/active_support/version.rb
index 20b91ac911..e2afb871e7 100644
--- a/activesupport/lib/active_support/version.rb
+++ b/activesupport/lib/active_support/version.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "gem_version"
 
 module ActiveSupport
diff --git a/activesupport/lib/active_support/xml_mini.rb b/activesupport/lib/active_support/xml_mini.rb
index 782fb41288..7163dee68a 100644
--- a/activesupport/lib/active_support/xml_mini.rb
+++ b/activesupport/lib/active_support/xml_mini.rb
@@ -1,9 +1,10 @@
+# frozen_string_literal: true
 require "time"
 require "base64"
 require "bigdecimal"
-require "active_support/core_ext/module/delegation"
-require "active_support/core_ext/string/inflections"
-require "active_support/core_ext/date_time/calculations"
+require_relative "core_ext/module/delegation"
+require_relative "core_ext/string/inflections"
+require_relative "core_ext/date_time/calculations"
 
 module ActiveSupport
   # = XmlMini
@@ -197,7 +198,7 @@ module ActiveSupport
         if name.is_a?(Module)
           name
         else
-          require "active_support/xml_mini/#{name.downcase}"
+          require_relative "xml_mini/#{name.downcase}"
           ActiveSupport.const_get("XmlMini_#{name}")
         end
       end
diff --git a/activesupport/lib/active_support/xml_mini/jdom.rb b/activesupport/lib/active_support/xml_mini/jdom.rb
index a7939b3185..8529c5f73b 100644
--- a/activesupport/lib/active_support/xml_mini/jdom.rb
+++ b/activesupport/lib/active_support/xml_mini/jdom.rb
@@ -1,9 +1,10 @@
+# frozen_string_literal: true
 raise "JRuby is required to use the JDOM backend for XmlMini" unless RUBY_PLATFORM.include?("java")
 
 require "jruby"
 include Java
 
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 
 java_import javax.xml.parsers.DocumentBuilder unless defined? DocumentBuilder
 java_import javax.xml.parsers.DocumentBuilderFactory unless defined? DocumentBuilderFactory
diff --git a/activesupport/lib/active_support/xml_mini/libxml.rb b/activesupport/lib/active_support/xml_mini/libxml.rb
index d849cdfa6b..2524d6aee2 100644
--- a/activesupport/lib/active_support/xml_mini/libxml.rb
+++ b/activesupport/lib/active_support/xml_mini/libxml.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "libxml"
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 require "stringio"
 
 module ActiveSupport
@@ -53,7 +54,7 @@ module LibXML #:nodoc:
           if c.element?
             c.to_hash(node_hash)
           elsif c.text? || c.cdata?
-            node_hash[CONTENT_ROOT] ||= ""
+            node_hash[CONTENT_ROOT] ||= "".dup
             node_hash[CONTENT_ROOT] << c.content
           end
         end
diff --git a/activesupport/lib/active_support/xml_mini/libxmlsax.rb b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
index f3d485da2f..8ea4e9b292 100644
--- a/activesupport/lib/active_support/xml_mini/libxmlsax.rb
+++ b/activesupport/lib/active_support/xml_mini/libxmlsax.rb
@@ -1,5 +1,6 @@
+# frozen_string_literal: true
 require "libxml"
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 require "stringio"
 
 module ActiveSupport
@@ -21,7 +22,7 @@ module ActiveSupport
       end
 
       def on_start_document
-        @hash = { CONTENT_KEY => "" }
+        @hash = { CONTENT_KEY => "".dup }
         @hash_stack = [@hash]
       end
 
@@ -31,7 +32,7 @@ module ActiveSupport
       end
 
       def on_start_element(name, attrs = {})
-        new_hash = { CONTENT_KEY => "" }.merge!(attrs)
+        new_hash = { CONTENT_KEY => "".dup }.merge!(attrs)
         new_hash[HASH_SIZE_KEY] = new_hash.size + 1
 
         case current_hash[name]
diff --git a/activesupport/lib/active_support/xml_mini/nokogiri.rb b/activesupport/lib/active_support/xml_mini/nokogiri.rb
index 63466c08b2..087112830e 100644
--- a/activesupport/lib/active_support/xml_mini/nokogiri.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogiri.rb
@@ -1,10 +1,11 @@
+# frozen_string_literal: true
 begin
   require "nokogiri"
 rescue LoadError => e
   $stderr.puts "You don't have nokogiri installed in your application. Please add it to your Gemfile and run bundle install"
   raise e
 end
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 require "stringio"
 
 module ActiveSupport
@@ -57,7 +58,7 @@ module ActiveSupport
             if c.element?
               c.to_hash(node_hash)
             elsif c.text? || c.cdata?
-              node_hash[CONTENT_ROOT] ||= ""
+              node_hash[CONTENT_ROOT] ||= "".dup
               node_hash[CONTENT_ROOT] << c.content
             end
           end
diff --git a/activesupport/lib/active_support/xml_mini/nokogirisax.rb b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
index 54e15e6a5f..7a9cd88af7 100644
--- a/activesupport/lib/active_support/xml_mini/nokogirisax.rb
+++ b/activesupport/lib/active_support/xml_mini/nokogirisax.rb
@@ -1,10 +1,11 @@
+# frozen_string_literal: true
 begin
   require "nokogiri"
 rescue LoadError => e
   $stderr.puts "You don't have nokogiri installed in your application. Please add it to your Gemfile and run bundle install"
   raise e
 end
-require "active_support/core_ext/object/blank"
+require_relative "../core_ext/object/blank"
 require "stringio"
 
 module ActiveSupport
@@ -37,7 +38,7 @@ module ActiveSupport
       end
 
       def start_element(name, attrs = [])
-        new_hash = { CONTENT_KEY => "" }.merge!(Hash[attrs])
+        new_hash = { CONTENT_KEY => "".dup }.merge!(Hash[attrs])
         new_hash[HASH_SIZE_KEY] = new_hash.size + 1
 
         case current_hash[name]
diff --git a/activesupport/lib/active_support/xml_mini/rexml.rb b/activesupport/lib/active_support/xml_mini/rexml.rb
index 03fa910fa5..a5fea919a7 100644
--- a/activesupport/lib/active_support/xml_mini/rexml.rb
+++ b/activesupport/lib/active_support/xml_mini/rexml.rb
@@ -1,5 +1,6 @@
-require "active_support/core_ext/kernel/reporting"
-require "active_support/core_ext/object/blank"
+# frozen_string_literal: true
+require_relative "../core_ext/kernel/reporting"
+require_relative "../core_ext/object/blank"
 require "stringio"
 
 module ActiveSupport
@@ -74,7 +75,7 @@ module ActiveSupport
           hash
         else
           # must use value to prevent double-escaping
-          texts = ""
+          texts = "".dup
           element.texts.each { |t| texts << t.value }
           merge!(hash, CONTENT_KEY, texts)
         end
diff --git a/activesupport/test/abstract_unit.rb b/activesupport/test/abstract_unit.rb
index c4f34c0abf..3004272629 100644
--- a/activesupport/test/abstract_unit.rb
+++ b/activesupport/test/abstract_unit.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 ORIG_ARGV = ARGV.dup
 
 require "active_support/core_ext/kernel/reporting"
diff --git a/activesupport/test/array_inquirer_test.rb b/activesupport/test/array_inquirer_test.rb
index 5b2bc82905..c674a80d29 100644
--- a/activesupport/test/array_inquirer_test.rb
+++ b/activesupport/test/array_inquirer_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 
diff --git a/activesupport/test/autoload_test.rb b/activesupport/test/autoload_test.rb
index 6c8aa3e055..65838041ea 100644
--- a/activesupport/test/autoload_test.rb
+++ b/activesupport/test/autoload_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class TestAutoloadModule < ActiveSupport::TestCase
diff --git a/activesupport/test/autoloading_fixtures/a/b.rb b/activesupport/test/autoloading_fixtures/a/b.rb
index 0dbbbbd181..8f2d83719d 100644
--- a/activesupport/test/autoloading_fixtures/a/b.rb
+++ b/activesupport/test/autoloading_fixtures/a/b.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class A::B
 end
diff --git a/activesupport/test/autoloading_fixtures/a/c/d.rb b/activesupport/test/autoloading_fixtures/a/c/d.rb
index 2c0ec5f182..fd50bb95c6 100644
--- a/activesupport/test/autoloading_fixtures/a/c/d.rb
+++ b/activesupport/test/autoloading_fixtures/a/c/d.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class A::C::D
 end
diff --git a/activesupport/test/autoloading_fixtures/a/c/em/f.rb b/activesupport/test/autoloading_fixtures/a/c/em/f.rb
index 3ff1b7efa0..298b63c916 100644
--- a/activesupport/test/autoloading_fixtures/a/c/em/f.rb
+++ b/activesupport/test/autoloading_fixtures/a/c/em/f.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class A::C::EM::F
 end
diff --git a/activesupport/test/autoloading_fixtures/application.rb b/activesupport/test/autoloading_fixtures/application.rb
index d7d3096dcb..ae3ccf487e 100644
--- a/activesupport/test/autoloading_fixtures/application.rb
+++ b/activesupport/test/autoloading_fixtures/application.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 ApplicationController = 10
diff --git a/activesupport/test/autoloading_fixtures/circular1.rb b/activesupport/test/autoloading_fixtures/circular1.rb
index a45761f066..f6041bde77 100644
--- a/activesupport/test/autoloading_fixtures/circular1.rb
+++ b/activesupport/test/autoloading_fixtures/circular1.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 silence_warnings do
   Circular2
 end
diff --git a/activesupport/test/autoloading_fixtures/circular2.rb b/activesupport/test/autoloading_fixtures/circular2.rb
index c847fa5001..178bbca3bd 100644
--- a/activesupport/test/autoloading_fixtures/circular2.rb
+++ b/activesupport/test/autoloading_fixtures/circular2.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 Circular1
 
 class Circular2
diff --git a/activesupport/test/autoloading_fixtures/class_folder.rb b/activesupport/test/autoloading_fixtures/class_folder.rb
index 6ee8182214..48c2993600 100644
--- a/activesupport/test/autoloading_fixtures/class_folder.rb
+++ b/activesupport/test/autoloading_fixtures/class_folder.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class ClassFolder
   ConstantInClassFolder = "indeed"
 end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb b/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb
index 4df069cab6..866d3547f6 100644
--- a/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb
+++ b/activesupport/test/autoloading_fixtures/class_folder/class_folder_subclass.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class ClassFolder::ClassFolderSubclass < ClassFolder
   ConstantInClassFolder = "indeed"
 end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb b/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb
index 8235e90724..6c20a3a9a7 100644
--- a/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb
+++ b/activesupport/test/autoloading_fixtures/class_folder/inline_class.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class ClassFolder::InlineClass
 end
diff --git a/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb b/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb
index 57a13d89ea..ee35eac3fc 100644
--- a/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb
+++ b/activesupport/test/autoloading_fixtures/class_folder/nested_class.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class ClassFolder
   class NestedClass
   end
diff --git a/activesupport/test/autoloading_fixtures/conflict.rb b/activesupport/test/autoloading_fixtures/conflict.rb
index d7f42b5d5f..6731ea51d8 100644
--- a/activesupport/test/autoloading_fixtures/conflict.rb
+++ b/activesupport/test/autoloading_fixtures/conflict.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 Conflict = 2
diff --git a/activesupport/test/autoloading_fixtures/counting_loader.rb b/activesupport/test/autoloading_fixtures/counting_loader.rb
index 4225c4412c..2a4001b815 100644
--- a/activesupport/test/autoloading_fixtures/counting_loader.rb
+++ b/activesupport/test/autoloading_fixtures/counting_loader.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 $counting_loaded_times ||= 0
 $counting_loaded_times += 1
 
diff --git a/activesupport/test/autoloading_fixtures/cross_site_dependency.rb b/activesupport/test/autoloading_fixtures/cross_site_dependency.rb
index de941bf271..4eff14e888 100644
--- a/activesupport/test/autoloading_fixtures/cross_site_dependency.rb
+++ b/activesupport/test/autoloading_fixtures/cross_site_dependency.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class CrossSiteDependency
 end
diff --git a/activesupport/test/autoloading_fixtures/d.rb b/activesupport/test/autoloading_fixtures/d.rb
index 52850e1e1a..c4217362d8 100644
--- a/activesupport/test/autoloading_fixtures/d.rb
+++ b/activesupport/test/autoloading_fixtures/d.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class D
 end
diff --git a/activesupport/test/autoloading_fixtures/em.rb b/activesupport/test/autoloading_fixtures/em.rb
index e47024999e..38bb323e9e 100644
--- a/activesupport/test/autoloading_fixtures/em.rb
+++ b/activesupport/test/autoloading_fixtures/em.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class EM
 end
diff --git a/activesupport/test/autoloading_fixtures/html/some_class.rb b/activesupport/test/autoloading_fixtures/html/some_class.rb
index b43d15d891..495372fef3 100644
--- a/activesupport/test/autoloading_fixtures/html/some_class.rb
+++ b/activesupport/test/autoloading_fixtures/html/some_class.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module HTML
   class SomeClass
   end
diff --git a/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb b/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb
index d2c4f6b0c5..e5f73d9f0c 100644
--- a/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb
+++ b/activesupport/test/autoloading_fixtures/load_path/loaded_constant.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 module LoadedConstant
 end
diff --git a/activesupport/test/autoloading_fixtures/loads_constant.rb b/activesupport/test/autoloading_fixtures/loads_constant.rb
index 0b30dc8bca..cb7b381de3 100644
--- a/activesupport/test/autoloading_fixtures/loads_constant.rb
+++ b/activesupport/test/autoloading_fixtures/loads_constant.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module LoadsConstant
 end
 
diff --git a/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb b/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb
index ca83437046..5ed98cd4cf 100644
--- a/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb
+++ b/activesupport/test/autoloading_fixtures/module_folder/inline_class.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class ModuleFolder::InlineClass
 end
diff --git a/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb b/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb
index fc4076bd0a..afed4b0a7e 100644
--- a/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb
+++ b/activesupport/test/autoloading_fixtures/module_folder/nested_class.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module ModuleFolder
   class NestedClass
   end
diff --git a/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb b/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb
index 04c426833e..a16cc566dd 100644
--- a/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb
+++ b/activesupport/test/autoloading_fixtures/module_folder/nested_sibling.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class ModuleFolder::NestedSibling
 end
diff --git a/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb b/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb
index 4f2020c503..a6ed49e0be 100644
--- a/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb
+++ b/activesupport/test/autoloading_fixtures/module_with_custom_const_missing/a/b.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 ModuleWithCustomConstMissing::A::B = "10"
diff --git a/activesupport/test/autoloading_fixtures/multiple_constant_file.rb b/activesupport/test/autoloading_fixtures/multiple_constant_file.rb
index a9ff4eb89c..33d371c830 100644
--- a/activesupport/test/autoloading_fixtures/multiple_constant_file.rb
+++ b/activesupport/test/autoloading_fixtures/multiple_constant_file.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 MultipleConstantFile = 10
 SiblingConstant = MultipleConstantFile * 2
diff --git a/activesupport/test/autoloading_fixtures/prepend.rb b/activesupport/test/autoloading_fixtures/prepend.rb
index 3134d1df2b..1bef4ab5b3 100644
--- a/activesupport/test/autoloading_fixtures/prepend.rb
+++ b/activesupport/test/autoloading_fixtures/prepend.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class SubClassConflict
 end
 
diff --git a/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb b/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb
index 090dda3043..d76b575b06 100644
--- a/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb
+++ b/activesupport/test/autoloading_fixtures/prepend/sub_class_conflict.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class Prepend::SubClassConflict
 end
diff --git a/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb b/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb
index e477ab21d0..814c41c004 100644
--- a/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb
+++ b/activesupport/test/autoloading_fixtures/raises_arbitrary_exception.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 RaisesArbitraryException = 1
 _ = A::B # Autoloading recursion, also expected to be watched and discarded.
 
diff --git a/activesupport/test/autoloading_fixtures/raises_name_error.rb b/activesupport/test/autoloading_fixtures/raises_name_error.rb
index a49960abf0..051f839994 100644
--- a/activesupport/test/autoloading_fixtures/raises_name_error.rb
+++ b/activesupport/test/autoloading_fixtures/raises_name_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class RaisesNameError
   FooBarBaz
 end
diff --git a/activesupport/test/autoloading_fixtures/raises_no_method_error.rb b/activesupport/test/autoloading_fixtures/raises_no_method_error.rb
index e1b8fce24a..1db51879c7 100644
--- a/activesupport/test/autoloading_fixtures/raises_no_method_error.rb
+++ b/activesupport/test/autoloading_fixtures/raises_no_method_error.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class RaisesNoMethodError
   self.foobar_method_doesnt_exist
 end
diff --git a/activesupport/test/autoloading_fixtures/requires_constant.rb b/activesupport/test/autoloading_fixtures/requires_constant.rb
index f04dcc4091..a26e265f71 100644
--- a/activesupport/test/autoloading_fixtures/requires_constant.rb
+++ b/activesupport/test/autoloading_fixtures/requires_constant.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "loaded_constant"
 
 module RequiresConstant
diff --git a/activesupport/test/autoloading_fixtures/should_not_be_required.rb b/activesupport/test/autoloading_fixtures/should_not_be_required.rb
index 1fcf170cc5..c1fada8213 100644
--- a/activesupport/test/autoloading_fixtures/should_not_be_required.rb
+++ b/activesupport/test/autoloading_fixtures/should_not_be_required.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 ShouldNotBeAutoloaded = 0
diff --git a/activesupport/test/autoloading_fixtures/throws.rb b/activesupport/test/autoloading_fixtures/throws.rb
index e1d96cc512..431111afbe 100644
--- a/activesupport/test/autoloading_fixtures/throws.rb
+++ b/activesupport/test/autoloading_fixtures/throws.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 Throws = 1
 _ = A::B # Autoloading recursion, expected to be discarded.
 
diff --git a/activesupport/test/autoloading_fixtures/typo.rb b/activesupport/test/autoloading_fixtures/typo.rb
index 0ffe07c2b3..0b74d73f3f 100644
--- a/activesupport/test/autoloading_fixtures/typo.rb
+++ b/activesupport/test/autoloading_fixtures/typo.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 TypO = 1
diff --git a/activesupport/test/benchmarkable_test.rb b/activesupport/test/benchmarkable_test.rb
index 210b9cb9fd..cb8cb89a30 100644
--- a/activesupport/test/benchmarkable_test.rb
+++ b/activesupport/test/benchmarkable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class BenchmarkableTest < ActiveSupport::TestCase
diff --git a/activesupport/test/broadcast_logger_test.rb b/activesupport/test/broadcast_logger_test.rb
index 184d0ebddd..c91e3f770f 100644
--- a/activesupport/test/broadcast_logger_test.rb
+++ b/activesupport/test/broadcast_logger_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 module ActiveSupport
diff --git a/activesupport/test/cache/behaviors.rb b/activesupport/test/cache/behaviors.rb
new file mode 100644
index 0000000000..c94cbc1156
--- /dev/null
+++ b/activesupport/test/cache/behaviors.rb
@@ -0,0 +1,8 @@
+# frozen_string_literal: true
+require_relative "behaviors/autoloading_cache_behavior"
+require_relative "behaviors/cache_delete_matched_behavior"
+require_relative "behaviors/cache_increment_decrement_behavior"
+require_relative "behaviors/cache_store_behavior"
+require_relative "behaviors/cache_store_version_behavior"
+require_relative "behaviors/encoded_key_cache_behavior"
+require_relative "behaviors/local_cache_behavior"
diff --git a/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb b/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb
new file mode 100644
index 0000000000..41a3a873b6
--- /dev/null
+++ b/activesupport/test/cache/behaviors/autoloading_cache_behavior.rb
@@ -0,0 +1,42 @@
+# frozen_string_literal: true
+require "dependencies_test_helpers"
+
+module AutoloadingCacheBehavior
+  include DependenciesTestHelpers
+
+  def test_simple_autoloading
+    with_autoloading_fixtures do
+      @cache.write("foo", EM.new)
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      assert_kind_of EM, @cache.read("foo")
+    end
+
+    remove_constants(:EM)
+    ActiveSupport::Dependencies.clear
+  end
+
+  def test_two_classes_autoloading
+    with_autoloading_fixtures do
+      @cache.write("foo", [EM.new, ClassFolder.new])
+    end
+
+    remove_constants(:EM, :ClassFolder)
+    ActiveSupport::Dependencies.clear
+
+    with_autoloading_fixtures do
+      loaded = @cache.read("foo")
+      assert_kind_of Array, loaded
+      assert_equal 2, loaded.size
+      assert_kind_of EM, loaded[0]
+      assert_kind_of ClassFolder, loaded[1]
+    end
+
+    remove_constants(:EM, :ClassFolder)
+    ActiveSupport::Dependencies.clear
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb b/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb
new file mode 100644
index 0000000000..b2cd919da9
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_delete_matched_behavior.rb
@@ -0,0 +1,14 @@
+# frozen_string_literal: true
+module CacheDeleteMatchedBehavior
+  def test_delete_matched
+    @cache.write("foo", "bar")
+    @cache.write("fu", "baz")
+    @cache.write("foo/bar", "baz")
+    @cache.write("fu/baz", "bar")
+    @cache.delete_matched(/oo/)
+    assert !@cache.exist?("foo")
+    assert @cache.exist?("fu")
+    assert !@cache.exist?("foo/bar")
+    assert @cache.exist?("fu/baz")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb b/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb
new file mode 100644
index 0000000000..45f92f10b2
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_increment_decrement_behavior.rb
@@ -0,0 +1,22 @@
+# frozen_string_literal: true
+module CacheIncrementDecrementBehavior
+  def test_increment
+    @cache.write("foo", 1, raw: true)
+    assert_equal 1, @cache.read("foo").to_i
+    assert_equal 2, @cache.increment("foo")
+    assert_equal 2, @cache.read("foo").to_i
+    assert_equal 3, @cache.increment("foo")
+    assert_equal 3, @cache.read("foo").to_i
+    assert_nil @cache.increment("bar")
+  end
+
+  def test_decrement
+    @cache.write("foo", 3, raw: true)
+    assert_equal 3, @cache.read("foo").to_i
+    assert_equal 2, @cache.decrement("foo")
+    assert_equal 2, @cache.read("foo").to_i
+    assert_equal 1, @cache.decrement("foo")
+    assert_equal 1, @cache.read("foo").to_i
+    assert_nil @cache.decrement("bar")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_store_behavior.rb b/activesupport/test/cache/behaviors/cache_store_behavior.rb
new file mode 100644
index 0000000000..32373644cf
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_store_behavior.rb
@@ -0,0 +1,330 @@
+# frozen_string_literal: true
+# Tests the base functionality that should be identical across all cache stores.
+module CacheStoreBehavior
+  def test_should_read_and_write_strings
+    assert @cache.write("foo", "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_should_overwrite
+    @cache.write("foo", "bar")
+    @cache.write("foo", "baz")
+    assert_equal "baz", @cache.read("foo")
+  end
+
+  def test_fetch_without_cache_miss
+    @cache.write("foo", "bar")
+    assert_not_called(@cache, :write) do
+      assert_equal "bar", @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_cache_miss
+    assert_called_with(@cache, :write, ["foo", "baz", @cache.options]) do
+      assert_equal "baz", @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_cache_miss_passes_key_to_block
+    cache_miss = false
+    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
+    assert cache_miss
+
+    cache_miss = false
+    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
+    assert !cache_miss
+  end
+
+  def test_fetch_with_forced_cache_miss
+    @cache.write("foo", "bar")
+    assert_not_called(@cache, :read) do
+      assert_called_with(@cache, :write, ["foo", "bar", @cache.options.merge(force: true)]) do
+        @cache.fetch("foo", force: true) { "bar" }
+      end
+    end
+  end
+
+  def test_fetch_with_cached_nil
+    @cache.write("foo", nil)
+    assert_not_called(@cache, :write) do
+      assert_nil @cache.fetch("foo") { "baz" }
+    end
+  end
+
+  def test_fetch_with_forced_cache_miss_with_block
+    @cache.write("foo", "bar")
+    assert_equal "foo_bar", @cache.fetch("foo", force: true) { "foo_bar" }
+  end
+
+  def test_fetch_with_forced_cache_miss_without_block
+    @cache.write("foo", "bar")
+    assert_raises(ArgumentError) do
+      @cache.fetch("foo", force: true)
+    end
+
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_should_read_and_write_hash
+    assert @cache.write("foo", a: "b")
+    assert_equal({ a: "b" }, @cache.read("foo"))
+  end
+
+  def test_should_read_and_write_integer
+    assert @cache.write("foo", 1)
+    assert_equal 1, @cache.read("foo")
+  end
+
+  def test_should_read_and_write_nil
+    assert @cache.write("foo", nil)
+    assert_nil @cache.read("foo")
+  end
+
+  def test_should_read_and_write_false
+    assert @cache.write("foo", false)
+    assert_equal false, @cache.read("foo")
+  end
+
+  def test_read_multi
+    @cache.write("foo", "bar")
+    @cache.write("fu", "baz")
+    @cache.write("fud", "biz")
+    assert_equal({ "foo" => "bar", "fu" => "baz" }, @cache.read_multi("foo", "fu"))
+  end
+
+  def test_read_multi_with_expires
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 10)
+    @cache.write("fu", "baz")
+    @cache.write("fud", "biz")
+    Time.stub(:now, time + 11) do
+      assert_equal({ "fu" => "baz" }, @cache.read_multi("foo", "fu"))
+    end
+  end
+
+  def test_fetch_multi
+    @cache.write("foo", "bar")
+    @cache.write("fud", "biz")
+
+    values = @cache.fetch_multi("foo", "fu", "fud") { |value| value * 2 }
+
+    assert_equal({ "foo" => "bar", "fu" => "fufu", "fud" => "biz" }, values)
+    assert_equal("fufu", @cache.read("fu"))
+  end
+
+  def test_multi_with_objects
+    cache_struct = Struct.new(:cache_key, :title)
+    foo = cache_struct.new("foo", "FOO!")
+    bar = cache_struct.new("bar")
+
+    @cache.write("bar", "BAM!")
+
+    values = @cache.fetch_multi(foo, bar) { |object| object.title }
+
+    assert_equal({ foo => "FOO!", bar => "BAM!" }, values)
+  end
+
+  def test_fetch_multi_without_block
+    assert_raises(ArgumentError) do
+      @cache.fetch_multi("foo")
+    end
+  end
+
+  def test_read_and_write_compressed_small_data
+    @cache.write("foo", "bar", compress: true)
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_read_and_write_compressed_large_data
+    @cache.write("foo", "bar", compress: true, compress_threshold: 2)
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_read_and_write_compressed_nil
+    @cache.write("foo", nil, compress: true)
+    assert_nil @cache.read("foo")
+  end
+
+  def test_cache_key
+    obj = Object.new
+    def obj.cache_key
+      :foo
+    end
+    @cache.write(obj, "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_param_as_cache_key
+    obj = Object.new
+    def obj.to_param
+      "foo"
+    end
+    @cache.write(obj, "bar")
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_array_as_cache_key
+    @cache.write([:fu, "foo"], "bar")
+    assert_equal "bar", @cache.read("fu/foo")
+  end
+
+  def test_hash_as_cache_key
+    @cache.write({ foo: 1, fu: 2 }, "bar")
+    assert_equal "bar", @cache.read("foo=1/fu=2")
+  end
+
+  def test_keys_are_case_sensitive
+    @cache.write("foo", "bar")
+    assert_nil @cache.read("FOO")
+  end
+
+  def test_exist
+    @cache.write("foo", "bar")
+    assert_equal true, @cache.exist?("foo")
+    assert_equal false, @cache.exist?("bar")
+  end
+
+  def test_nil_exist
+    @cache.write("foo", nil)
+    assert @cache.exist?("foo")
+  end
+
+  def test_delete
+    @cache.write("foo", "bar")
+    assert @cache.exist?("foo")
+    assert @cache.delete("foo")
+    assert !@cache.exist?("foo")
+  end
+
+  def test_original_store_objects_should_not_be_immutable
+    bar = "bar".dup
+    @cache.write("foo", bar)
+    assert_nothing_raised { bar.gsub!(/.*/, "baz") }
+  end
+
+  def test_expires_in
+    time = Time.local(2008, 4, 24)
+
+    Time.stub(:now, time) do
+      @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo")
+    end
+
+    Time.stub(:now, time + 30) do
+      assert_equal "bar", @cache.read("foo")
+    end
+
+    Time.stub(:now, time + 61) do
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_race_condition_protection_skipped_if_not_defined
+    @cache.write("foo", "bar")
+    time = @cache.send(:read_entry, @cache.send(:normalize_key, "foo", {}), {}).expires_at
+
+    Time.stub(:now, Time.at(time)) do
+      result = @cache.fetch("foo") do
+        assert_nil @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_race_condition_protection_is_limited
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 71) do
+      result = @cache.fetch("foo", race_condition_ttl: 10) do
+        assert_nil @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_race_condition_protection_is_safe
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 61) do
+      begin
+        @cache.fetch("foo", race_condition_ttl: 10) do
+          assert_equal "bar", @cache.read("foo")
+          raise ArgumentError.new
+        end
+      rescue ArgumentError
+      end
+      assert_equal "bar", @cache.read("foo")
+    end
+    Time.stub(:now, time + 91) do
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_race_condition_protection
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 60)
+    Time.stub(:now, time + 61) do
+      result = @cache.fetch("foo", race_condition_ttl: 10) do
+        assert_equal "bar", @cache.read("foo")
+        "baz"
+      end
+      assert_equal "baz", result
+    end
+  end
+
+  def test_crazy_key_characters
+    crazy_key = "#/:*(<+=> )&$%@?;'\"\'`~-"
+    assert @cache.write(crazy_key, "1", raw: true)
+    assert_equal "1", @cache.read(crazy_key)
+    assert_equal "1", @cache.fetch(crazy_key)
+    assert @cache.delete(crazy_key)
+    assert_equal "2", @cache.fetch(crazy_key, raw: true) { "2" }
+    assert_equal 3, @cache.increment(crazy_key)
+    assert_equal 2, @cache.decrement(crazy_key)
+  end
+
+  def test_really_long_keys
+    key = "".dup
+    900.times { key << "x" }
+    assert @cache.write(key, "bar")
+    assert_equal "bar", @cache.read(key)
+    assert_equal "bar", @cache.fetch(key)
+    assert_nil @cache.read("#{key}x")
+    assert_equal({ key => "bar" }, @cache.read_multi(key))
+    assert @cache.delete(key)
+  end
+
+  def test_cache_hit_instrumentation
+    key = "test_key"
+    @events = []
+    ActiveSupport::Notifications.subscribe "cache_read.active_support" do |*args|
+      @events << ActiveSupport::Notifications::Event.new(*args)
+    end
+    assert @cache.write(key, "1", raw: true)
+    assert @cache.fetch(key) {}
+    assert_equal 1, @events.length
+    assert_equal "cache_read.active_support", @events[0].name
+    assert_equal :fetch, @events[0].payload[:super_operation]
+    assert @events[0].payload[:hit]
+  ensure
+    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
+  end
+
+  def test_cache_miss_instrumentation
+    @events = []
+    ActiveSupport::Notifications.subscribe(/^cache_(.*)\.active_support$/) do |*args|
+      @events << ActiveSupport::Notifications::Event.new(*args)
+    end
+    assert_not @cache.fetch("bad_key") {}
+    assert_equal 3, @events.length
+    assert_equal "cache_read.active_support", @events[0].name
+    assert_equal "cache_generate.active_support", @events[1].name
+    assert_equal "cache_write.active_support", @events[2].name
+    assert_equal :fetch, @events[0].payload[:super_operation]
+    assert_not @events[0].payload[:hit]
+  ensure
+    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
+  end
+end
diff --git a/activesupport/test/cache/behaviors/cache_store_version_behavior.rb b/activesupport/test/cache/behaviors/cache_store_version_behavior.rb
new file mode 100644
index 0000000000..82f392c86a
--- /dev/null
+++ b/activesupport/test/cache/behaviors/cache_store_version_behavior.rb
@@ -0,0 +1,87 @@
+# frozen_string_literal: true
+module CacheStoreVersionBehavior
+  ModelWithKeyAndVersion = Struct.new(:cache_key, :cache_version)
+
+  def test_fetch_with_right_version_should_hit
+    @cache.fetch("foo", version: 1) { "bar" }
+    assert_equal "bar", @cache.read("foo", version: 1)
+  end
+
+  def test_fetch_with_wrong_version_should_miss
+    @cache.fetch("foo", version: 1) { "bar" }
+    assert_nil @cache.read("foo", version: 2)
+  end
+
+  def test_read_with_right_version_should_hit
+    @cache.write("foo", "bar", version: 1)
+    assert_equal "bar", @cache.read("foo", version: 1)
+  end
+
+  def test_read_with_wrong_version_should_miss
+    @cache.write("foo", "bar", version: 1)
+    assert_nil @cache.read("foo", version: 2)
+  end
+
+  def test_exist_with_right_version_should_be_true
+    @cache.write("foo", "bar", version: 1)
+    assert @cache.exist?("foo", version: 1)
+  end
+
+  def test_exist_with_wrong_version_should_be_false
+    @cache.write("foo", "bar", version: 1)
+    assert !@cache.exist?("foo", version: 2)
+  end
+
+  def test_reading_and_writing_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write(m1v1, "bar")
+    assert_equal "bar", @cache.read(m1v1)
+    assert_nil @cache.read(m1v2)
+  end
+
+  def test_reading_and_writing_with_model_supporting_cache_version_using_nested_key
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write([ "something", m1v1 ], "bar")
+    assert_equal "bar", @cache.read([ "something", m1v1 ])
+    assert_nil @cache.read([ "something", m1v2 ])
+  end
+
+  def test_fetching_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.fetch(m1v1) { "bar" }
+    assert_equal "bar", @cache.fetch(m1v1) { "bu" }
+    assert_equal "bu", @cache.fetch(m1v2) { "bu" }
+  end
+
+  def test_exist_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
+
+    @cache.write(m1v1, "bar")
+    assert     @cache.exist?(m1v1)
+    assert_not @cache.fetch(m1v2)
+  end
+
+  def test_fetch_multi_with_model_supporting_cache_version
+    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
+    m2v1 = ModelWithKeyAndVersion.new("model/2", 1)
+    m2v2 = ModelWithKeyAndVersion.new("model/2", 2)
+
+    first_fetch_values  = @cache.fetch_multi(m1v1, m2v1) { |m| m.cache_key }
+    second_fetch_values = @cache.fetch_multi(m1v1, m2v2) { |m| m.cache_key + " 2nd" }
+
+    assert_equal({ m1v1 => "model/1", m2v1 => "model/2" }, first_fetch_values)
+    assert_equal({ m1v1 => "model/1", m2v2 => "model/2 2nd" }, second_fetch_values)
+  end
+
+  def test_version_is_normalized
+    @cache.write("foo", "bar", version: 1)
+    assert_equal "bar", @cache.read("foo", version: "1")
+  end
+end
diff --git a/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
new file mode 100644
index 0000000000..361903ab82
--- /dev/null
+++ b/activesupport/test/cache/behaviors/encoded_key_cache_behavior.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+# https://rails.lighthouseapp.com/projects/8994/tickets/6225-memcachestore-cant-deal-with-umlauts-and-special-characters
+# The error is caused by character encodings that can't be compared with ASCII-8BIT regular expressions and by special
+# characters like the umlaut in UTF-8.
+module EncodedKeyCacheBehavior
+  Encoding.list.each do |encoding|
+    define_method "test_#{encoding.name.underscore}_encoded_values" do
+      key = "foo".dup.force_encoding(encoding)
+      assert @cache.write(key, "1", raw: true)
+      assert_equal "1", @cache.read(key)
+      assert_equal "1", @cache.fetch(key)
+      assert @cache.delete(key)
+      assert_equal "2", @cache.fetch(key, raw: true) { "2" }
+      assert_equal 3, @cache.increment(key)
+      assert_equal 2, @cache.decrement(key)
+    end
+  end
+
+  def test_common_utf8_values
+    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    assert @cache.write(key, "1", raw: true)
+    assert_equal "1", @cache.read(key)
+    assert_equal "1", @cache.fetch(key)
+    assert @cache.delete(key)
+    assert_equal "2", @cache.fetch(key, raw: true) { "2" }
+    assert_equal 3, @cache.increment(key)
+    assert_equal 2, @cache.decrement(key)
+  end
+
+  def test_retains_encoding
+    key = "\xC3\xBCmlaut".dup.force_encoding(Encoding::UTF_8)
+    assert @cache.write(key, "1", raw: true)
+    assert_equal Encoding::UTF_8, key.encoding
+  end
+end
diff --git a/activesupport/test/cache/behaviors/local_cache_behavior.rb b/activesupport/test/cache/behaviors/local_cache_behavior.rb
new file mode 100644
index 0000000000..730f0306b8
--- /dev/null
+++ b/activesupport/test/cache/behaviors/local_cache_behavior.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+module LocalCacheBehavior
+  def test_local_writes_are_persistent_on_the_remote_cache
+    retval = @cache.with_local_cache do
+      @cache.write("foo", "bar")
+    end
+    assert retval
+    assert_equal "bar", @cache.read("foo")
+  end
+
+  def test_clear_also_clears_local_cache
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.clear
+      assert_nil @cache.read("foo")
+    end
+
+    assert_nil @cache.read("foo")
+  end
+
+  def test_cleanup_clears_local_cache_but_not_remote_cache
+    skip unless @cache.class.instance_methods(false).include?(:cleanup)
+
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo")
+
+      @cache.send(:bypass_local_cache) { @cache.write("foo", "baz") }
+      assert_equal "bar", @cache.read("foo")
+
+      @cache.cleanup
+      assert_equal "baz", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_write
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @peek.delete("foo")
+      assert_equal "bar", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_read
+    @cache.write("foo", "bar")
+    @cache.with_local_cache do
+      assert_equal "bar", @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_read_nil
+    @cache.with_local_cache do
+      assert_nil @cache.read("foo")
+      @cache.send(:bypass_local_cache) { @cache.write "foo", "bar" }
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_fetch
+    @cache.with_local_cache do
+      @cache.send(:local_cache).write "foo", "bar"
+      assert_equal "bar", @cache.send(:local_cache).fetch("foo")
+    end
+  end
+
+  def test_local_cache_of_write_nil
+    @cache.with_local_cache do
+      assert @cache.write("foo", nil)
+      assert_nil @cache.read("foo")
+      @peek.write("foo", "bar")
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_write_with_unless_exist
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.write("foo", "baz", unless_exist: true)
+      assert_equal @peek.read("foo"), @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_delete
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @cache.delete("foo")
+      assert_nil @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_exist
+    @cache.with_local_cache do
+      @cache.write("foo", "bar")
+      @peek.delete("foo")
+      assert @cache.exist?("foo")
+    end
+  end
+
+  def test_local_cache_of_increment
+    @cache.with_local_cache do
+      @cache.write("foo", 1, raw: true)
+      @peek.write("foo", 2, raw: true)
+      @cache.increment("foo")
+      assert_equal 3, @cache.read("foo")
+    end
+  end
+
+  def test_local_cache_of_decrement
+    @cache.with_local_cache do
+      @cache.write("foo", 1, raw: true)
+      @peek.write("foo", 3, raw: true)
+      @cache.decrement("foo")
+      assert_equal 2, @cache.read("foo")
+    end
+  end
+
+  def test_middleware
+    app = lambda { |env|
+      result = @cache.write("foo", "bar")
+      assert_equal "bar", @cache.read("foo") # make sure 'foo' was written
+      assert result
+      [200, {}, []]
+    }
+    app = @cache.middleware.new(app)
+    app.call({})
+  end
+end
diff --git a/activesupport/test/cache/cache_entry_test.rb b/activesupport/test/cache/cache_entry_test.rb
new file mode 100644
index 0000000000..4a8fc5bed3
--- /dev/null
+++ b/activesupport/test/cache/cache_entry_test.rb
@@ -0,0 +1,29 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheEntryTest < ActiveSupport::TestCase
+  def test_expired
+    entry = ActiveSupport::Cache::Entry.new("value")
+    assert !entry.expired?, "entry not expired"
+    entry = ActiveSupport::Cache::Entry.new("value", expires_in: 60)
+    assert !entry.expired?, "entry not expired"
+    Time.stub(:now, Time.now + 61) do
+      assert entry.expired?, "entry is expired"
+    end
+  end
+
+  def test_compress_values
+    value = "value" * 100
+    entry = ActiveSupport::Cache::Entry.new(value, compress: true, compress_threshold: 1)
+    assert_equal value, entry.value
+    assert(value.bytesize > entry.size, "value is compressed")
+  end
+
+  def test_non_compress_values
+    value = "value" * 100
+    entry = ActiveSupport::Cache::Entry.new(value)
+    assert_equal value, entry.value
+    assert_equal value.bytesize, entry.size
+  end
+end
diff --git a/activesupport/test/cache/cache_key_test.rb b/activesupport/test/cache/cache_key_test.rb
new file mode 100644
index 0000000000..19c40d44d6
--- /dev/null
+++ b/activesupport/test/cache/cache_key_test.rb
@@ -0,0 +1,89 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheKeyTest < ActiveSupport::TestCase
+  def test_entry_legacy_optional_ivars
+    legacy = Class.new(ActiveSupport::Cache::Entry) do
+      def initialize(value, options = {})
+        @value = value
+        @expires_in = nil
+        @created_at = nil
+        super
+      end
+    end
+
+    entry = legacy.new "foo"
+    assert_equal "foo", entry.value
+  end
+
+  def test_expand_cache_key
+    assert_equal "1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true])
+    assert_equal "name/1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true], :name)
+  end
+
+  def test_expand_cache_key_with_rails_cache_id
+    with_env("RAILS_CACHE_ID" => "c99") do
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key([:foo])
+      assert_equal "c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar])
+      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key(:foo, :nm)
+      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key([:foo], :nm)
+      assert_equal "nm/c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar], :nm)
+    end
+  end
+
+  def test_expand_cache_key_with_rails_app_version
+    with_env("RAILS_APP_VERSION" => "rails3") do
+      assert_equal "rails3/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+    end
+  end
+
+  def test_expand_cache_key_rails_cache_id_should_win_over_rails_app_version
+    with_env("RAILS_CACHE_ID" => "c99", "RAILS_APP_VERSION" => "rails3") do
+      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
+    end
+  end
+
+  def test_expand_cache_key_respond_to_cache_key
+    key = "foo".dup
+    def key.cache_key
+      :foo_key
+    end
+    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key(key)
+  end
+
+  def test_expand_cache_key_array_with_something_that_responds_to_cache_key
+    key = "foo".dup
+    def key.cache_key
+      :foo_key
+    end
+    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key([key])
+  end
+
+  def test_expand_cache_key_of_nil
+    assert_equal "", ActiveSupport::Cache.expand_cache_key(nil)
+  end
+
+  def test_expand_cache_key_of_false
+    assert_equal "false", ActiveSupport::Cache.expand_cache_key(false)
+  end
+
+  def test_expand_cache_key_of_true
+    assert_equal "true", ActiveSupport::Cache.expand_cache_key(true)
+  end
+
+  def test_expand_cache_key_of_array_like_object
+    assert_equal "foo/bar/baz", ActiveSupport::Cache.expand_cache_key(%w{foo bar baz}.to_enum)
+  end
+
+  private
+
+    def with_env(kv)
+      old_values = {}
+      kv.each { |key, value| old_values[key], ENV[key] = ENV[key], value }
+      yield
+    ensure
+      old_values.each { |key, value| ENV[key] = value }
+    end
+end
diff --git a/activesupport/test/cache/cache_store_logger_test.rb b/activesupport/test/cache/cache_store_logger_test.rb
new file mode 100644
index 0000000000..3014c4d57f
--- /dev/null
+++ b/activesupport/test/cache/cache_store_logger_test.rb
@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreLoggerTest < ActiveSupport::TestCase
+  def setup
+    @cache = ActiveSupport::Cache.lookup_store(:memory_store)
+
+    @buffer = StringIO.new
+    @cache.logger = ActiveSupport::Logger.new(@buffer)
+  end
+
+  def test_logging
+    @cache.fetch("foo") { "bar" }
+    assert @buffer.string.present?
+  end
+
+  def test_log_with_string_namespace
+    @cache.fetch("foo", namespace: "string_namespace") { "bar" }
+    assert_match %r{string_namespace:foo}, @buffer.string
+  end
+
+  def test_log_with_proc_namespace
+    proc = Proc.new do
+      "proc_namespace"
+    end
+    @cache.fetch("foo", namespace: proc) { "bar" }
+    assert_match %r{proc_namespace:foo}, @buffer.string
+  end
+
+  def test_mute_logging
+    @cache.mute { @cache.fetch("foo") { "bar" } }
+    assert @buffer.string.blank?
+  end
+end
diff --git a/activesupport/test/cache/cache_store_namespace_test.rb b/activesupport/test/cache/cache_store_namespace_test.rb
new file mode 100644
index 0000000000..8df048aad0
--- /dev/null
+++ b/activesupport/test/cache/cache_store_namespace_test.rb
@@ -0,0 +1,39 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreNamespaceTest < ActiveSupport::TestCase
+  def test_static_namespace
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
+    cache.write("foo", "bar")
+    assert_equal "bar", cache.read("foo")
+    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
+  end
+
+  def test_proc_namespace
+    test_val = "tester"
+    proc = lambda { test_val }
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: proc)
+    cache.write("foo", "bar")
+    assert_equal "bar", cache.read("foo")
+    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
+  end
+
+  def test_delete_matched_key_start
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
+    cache.write("foo", "bar")
+    cache.write("fu", "baz")
+    cache.delete_matched(/^fo/)
+    assert !cache.exist?("foo")
+    assert cache.exist?("fu")
+  end
+
+  def test_delete_matched_key
+    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "foo")
+    cache.write("foo", "bar")
+    cache.write("fu", "baz")
+    cache.delete_matched(/OO/i)
+    assert !cache.exist?("foo")
+    assert cache.exist?("fu")
+  end
+end
diff --git a/activesupport/test/cache/cache_store_setting_test.rb b/activesupport/test/cache/cache_store_setting_test.rb
new file mode 100644
index 0000000000..cc126ec930
--- /dev/null
+++ b/activesupport/test/cache/cache_store_setting_test.rb
@@ -0,0 +1,67 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+require "dalli"
+
+class CacheStoreSettingTest < ActiveSupport::TestCase
+  def test_memory_store_gets_created_if_no_arguments_passed_to_lookup_store_method
+    store = ActiveSupport::Cache.lookup_store
+    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
+  end
+
+  def test_memory_store
+    store = ActiveSupport::Cache.lookup_store :memory_store
+    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
+  end
+
+  def test_file_fragment_cache_store
+    store = ActiveSupport::Cache.lookup_store :file_store, "/path/to/cache/directory"
+    assert_kind_of(ActiveSupport::Cache::FileStore, store)
+    assert_equal "/path/to/cache/directory", store.cache_path
+  end
+
+  def test_mem_cache_fragment_cache_store
+    assert_called_with(Dalli::Client, :new, [%w[localhost], {}]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost"
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_given_mem_cache
+    mem_cache = Dalli::Client.new
+    assert_not_called(Dalli::Client, :new) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, mem_cache
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_not_dalli_client
+    assert_not_called(Dalli::Client, :new) do
+      memcache = Object.new
+      assert_raises(ArgumentError) do
+        ActiveSupport::Cache.lookup_store :mem_cache_store, memcache
+      end
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_multiple_servers
+    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], {}]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1"
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+    end
+  end
+
+  def test_mem_cache_fragment_cache_store_with_options
+    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], { timeout: 10 }]) do
+      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1", namespace: "foo", timeout: 10
+      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
+      assert_equal "foo", store.options[:namespace]
+    end
+  end
+
+  def test_object_assigned_fragment_cache_store
+    store = ActiveSupport::Cache.lookup_store ActiveSupport::Cache::FileStore.new("/path/to/cache/directory")
+    assert_kind_of(ActiveSupport::Cache::FileStore, store)
+    assert_equal "/path/to/cache/directory", store.cache_path
+  end
+end
diff --git a/activesupport/test/cache/cache_store_write_multi_test.rb b/activesupport/test/cache/cache_store_write_multi_test.rb
new file mode 100644
index 0000000000..9355dde0f4
--- /dev/null
+++ b/activesupport/test/cache/cache_store_write_multi_test.rb
@@ -0,0 +1,61 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+class CacheStoreWriteMultiEntriesStoreProviderInterfaceTest < ActiveSupport::TestCase
+  setup do
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  test "fetch_multi uses write_multi_entries store provider interface" do
+    assert_called_with(@cache, :write_multi_entries) do
+      @cache.fetch_multi "a", "b", "c" do |key|
+        key * 2
+      end
+    end
+  end
+end
+
+class CacheStoreWriteMultiInstrumentationTest < ActiveSupport::TestCase
+  setup do
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  test "instrumentation" do
+    writes = { "a" => "aa", "b" => "bb" }
+
+    events = with_instrumentation "write_multi" do
+      @cache.write_multi(writes)
+    end
+
+    assert_equal %w[ cache_write_multi.active_support ], events.map(&:name)
+    assert_nil events[0].payload[:super_operation]
+    assert_equal({ "a" => "aa", "b" => "bb" }, events[0].payload[:key])
+  end
+
+  test "instrumentation with fetch_multi as super operation" do
+    skip "fetch_multi isn't instrumented yet"
+
+    events = with_instrumentation "write_multi" do
+      @cache.fetch_multi("a", "b") { |key| key * 2 }
+    end
+
+    assert_equal %w[ cache_write_multi.active_support ], events.map(&:name)
+    assert_nil events[0].payload[:super_operation]
+    assert !events[0].payload[:hit]
+  end
+
+  private
+    def with_instrumentation(method)
+      event_name = "cache_#{method}.active_support"
+
+      [].tap do |events|
+        ActiveSupport::Notifications.subscribe event_name do |*args|
+          events << ActiveSupport::Notifications::Event.new(*args)
+        end
+        yield
+      end
+    ensure
+      ActiveSupport::Notifications.unsubscribe event_name
+    end
+end
diff --git a/activesupport/test/cache/local_cache_middleware_test.rb b/activesupport/test/cache/local_cache_middleware_test.rb
new file mode 100644
index 0000000000..3f0bd40fbd
--- /dev/null
+++ b/activesupport/test/cache/local_cache_middleware_test.rb
@@ -0,0 +1,62 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+
+module ActiveSupport
+  module Cache
+    module Strategy
+      module LocalCache
+        class MiddlewareTest < ActiveSupport::TestCase
+          def test_local_cache_cleared_on_close
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              [200, {}, []]
+            })
+            _, _, body = middleware.call({})
+            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
+            body.each {}
+            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
+            body.close
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_and_response_should_be_present_on_invalid_parameters_error
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              raise Rack::Utils::InvalidParameterError
+            })
+            response = middleware.call({})
+            assert response, "response should exist"
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_on_exception
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              raise
+            })
+            assert_raises(RuntimeError) { middleware.call({}) }
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+
+          def test_local_cache_cleared_on_throw
+            key = "super awesome key"
+            assert_nil LocalCacheRegistry.cache_for key
+            middleware = Middleware.new("<3", key).new(->(env) {
+              assert LocalCacheRegistry.cache_for(key), "should have a cache"
+              throw :warden
+            })
+            assert_throws(:warden) { middleware.call({}) }
+            assert_nil LocalCacheRegistry.cache_for(key)
+          end
+        end
+      end
+    end
+  end
+end
diff --git a/activesupport/test/cache/stores/file_store_test.rb b/activesupport/test/cache/stores/file_store_test.rb
new file mode 100644
index 0000000000..6ba25bbaec
--- /dev/null
+++ b/activesupport/test/cache/stores/file_store_test.rb
@@ -0,0 +1,129 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+require "pathname"
+
+class FileStoreTest < ActiveSupport::TestCase
+  def setup
+    Dir.mkdir(cache_dir) unless File.exist?(cache_dir)
+    @cache = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
+    @peek = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
+    @cache_with_pathname = ActiveSupport::Cache.lookup_store(:file_store, Pathname.new(cache_dir), expires_in: 60)
+
+    @buffer = StringIO.new
+    @cache.logger = ActiveSupport::Logger.new(@buffer)
+  end
+
+  def teardown
+    FileUtils.rm_r(cache_dir)
+  rescue Errno::ENOENT
+  end
+
+  def cache_dir
+    File.join(Dir.pwd, "tmp_cache")
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include LocalCacheBehavior
+  include CacheDeleteMatchedBehavior
+  include CacheIncrementDecrementBehavior
+  include AutoloadingCacheBehavior
+
+  def test_clear
+    gitkeep = File.join(cache_dir, ".gitkeep")
+    keep = File.join(cache_dir, ".keep")
+    FileUtils.touch([gitkeep, keep])
+    @cache.clear
+    assert File.exist?(gitkeep)
+    assert File.exist?(keep)
+  end
+
+  def test_clear_without_cache_dir
+    FileUtils.rm_r(cache_dir)
+    @cache.clear
+  end
+
+  def test_long_uri_encoded_keys
+    @cache.write("%" * 870, 1)
+    assert_equal 1, @cache.read("%" * 870)
+  end
+
+  def test_key_transformation
+    key = @cache.send(:normalize_key, "views/index?id=1", {})
+    assert_equal "views/index?id=1", @cache.send(:file_path_key, key)
+  end
+
+  def test_key_transformation_with_pathname
+    FileUtils.touch(File.join(cache_dir, "foo"))
+    key = @cache_with_pathname.send(:normalize_key, "views/index?id=1", {})
+    assert_equal "views/index?id=1", @cache_with_pathname.send(:file_path_key, key)
+  end
+
+  # Test that generated cache keys are short enough to have Tempfile stuff added to them and
+  # remain valid
+  def test_filename_max_size
+    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}"
+    path = @cache.send(:normalize_key, key, {})
+    Dir::Tmpname.create(path) do |tmpname, n, opts|
+      assert File.basename(tmpname + ".lock").length <= 255, "Temp filename too long: #{File.basename(tmpname + '.lock').length}"
+    end
+  end
+
+  # Because file systems have a maximum filename size, filenames > max size should be split in to directories
+  # If filename is 'AAAAB', where max size is 4, the returned path should be AAAA/B
+  def test_key_transformation_max_filename_size
+    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}B"
+    path = @cache.send(:normalize_key, key, {})
+    assert path.split("/").all? { |dir_name| dir_name.size <= ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE }
+    assert_equal "B", File.basename(path)
+  end
+
+  # If nothing has been stored in the cache, there is a chance the cache directory does not yet exist
+  # Ensure delete_matched gracefully handles this case
+  def test_delete_matched_when_cache_directory_does_not_exist
+    assert_nothing_raised do
+      ActiveSupport::Cache::FileStore.new("/test/cache/directory").delete_matched(/does_not_exist/)
+    end
+  end
+
+  def test_delete_does_not_delete_empty_parent_dir
+    sub_cache_dir = File.join(cache_dir, "subdir/")
+    sub_cache_store = ActiveSupport::Cache::FileStore.new(sub_cache_dir)
+    assert_nothing_raised do
+      assert sub_cache_store.write("foo", "bar")
+      assert sub_cache_store.delete("foo")
+    end
+    assert File.exist?(cache_dir), "Parent of top level cache dir was deleted!"
+    assert File.exist?(sub_cache_dir), "Top level cache dir was deleted!"
+    assert Dir.entries(sub_cache_dir).reject { |f| ActiveSupport::Cache::FileStore::EXCLUDED_DIRS.include?(f) }.empty?
+  end
+
+  def test_log_exception_when_cache_read_fails
+    File.stub(:exist?, -> { raise StandardError.new("failed") }) do
+      @cache.send(:read_entry, "winston", {})
+      assert @buffer.string.present?
+    end
+  end
+
+  def test_cleanup_removes_all_expired_entries
+    time = Time.now
+    @cache.write("foo", "bar", expires_in: 10)
+    @cache.write("baz", "qux")
+    @cache.write("quux", "corge", expires_in: 20)
+    Time.stub(:now, time + 15) do
+      @cache.cleanup
+      assert_not @cache.exist?("foo")
+      assert @cache.exist?("baz")
+      assert @cache.exist?("quux")
+    end
+  end
+
+  def test_write_with_unless_exist
+    assert_equal true, @cache.write(1, "aaaaaaaaaa")
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+    @cache.write(1, nil)
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+  end
+end
diff --git a/activesupport/test/cache/stores/mem_cache_store_test.rb b/activesupport/test/cache/stores/mem_cache_store_test.rb
new file mode 100644
index 0000000000..e188f5f881
--- /dev/null
+++ b/activesupport/test/cache/stores/mem_cache_store_test.rb
@@ -0,0 +1,75 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+require "dalli"
+
+class MemCacheStoreTest < ActiveSupport::TestCase
+  begin
+    ss = Dalli::Client.new("localhost:11211").stats
+    raise Dalli::DalliError unless ss["localhost:11211"]
+
+    MEMCACHE_UP = true
+  rescue Dalli::DalliError
+    $stderr.puts "Skipping memcached tests. Start memcached and try again."
+    MEMCACHE_UP = false
+  end
+
+  def setup
+    skip "memcache server is not up" unless MEMCACHE_UP
+
+    @cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, expires_in: 60)
+    @peek = ActiveSupport::Cache.lookup_store(:mem_cache_store)
+    @data = @cache.instance_variable_get(:@data)
+    @cache.clear
+    @cache.silence!
+    @cache.logger = ActiveSupport::Logger.new("/dev/null")
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include LocalCacheBehavior
+  include CacheIncrementDecrementBehavior
+  include EncodedKeyCacheBehavior
+  include AutoloadingCacheBehavior
+
+  def test_raw_values
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.write("foo", 2)
+    assert_equal "2", cache.read("foo")
+  end
+
+  def test_raw_values_with_marshal
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.write("foo", Marshal.dump([]))
+    assert_equal [], cache.read("foo")
+  end
+
+  def test_local_cache_raw_values
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.with_local_cache do
+      cache.write("foo", 2)
+      assert_equal "2", cache.read("foo")
+    end
+  end
+
+  def test_local_cache_raw_values_with_marshal
+    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
+    cache.clear
+    cache.with_local_cache do
+      cache.write("foo", Marshal.dump([]))
+      assert_equal [], cache.read("foo")
+    end
+  end
+
+  def test_read_should_return_a_different_object_id_each_time_it_is_called
+    @cache.write("foo", "bar")
+    value = @cache.read("foo")
+    assert_not_equal value.object_id, @cache.read("foo").object_id
+    value << "bingo"
+    assert_not_equal value, @cache.read("foo")
+  end
+end
diff --git a/activesupport/test/cache/stores/memory_store_test.rb b/activesupport/test/cache/stores/memory_store_test.rb
new file mode 100644
index 0000000000..e8dfe24a2f
--- /dev/null
+++ b/activesupport/test/cache/stores/memory_store_test.rb
@@ -0,0 +1,108 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+
+class MemoryStoreTest < ActiveSupport::TestCase
+  def setup
+    @record_size = ActiveSupport::Cache.lookup_store(:memory_store).send(:cached_size, 1, ActiveSupport::Cache::Entry.new("aaaaaaaaaa"))
+    @cache = ActiveSupport::Cache.lookup_store(:memory_store, expires_in: 60, size: @record_size * 10 + 1)
+  end
+
+  include CacheStoreBehavior
+  include CacheStoreVersionBehavior
+  include CacheDeleteMatchedBehavior
+  include CacheIncrementDecrementBehavior
+
+  def test_prune_size
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.read(2) && sleep(0.001)
+    @cache.read(4)
+    @cache.prune(@record_size * 3)
+    assert @cache.exist?(5)
+    assert @cache.exist?(4)
+    assert !@cache.exist?(3), "no entry"
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_prune_size_on_write
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.write(6, "ffffffffff") && sleep(0.001)
+    @cache.write(7, "gggggggggg") && sleep(0.001)
+    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
+    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
+    @cache.write(10, "kkkkkkkkkk") && sleep(0.001)
+    @cache.read(2) && sleep(0.001)
+    @cache.read(4) && sleep(0.001)
+    @cache.write(11, "llllllllll")
+    assert @cache.exist?(11)
+    assert @cache.exist?(10)
+    assert @cache.exist?(9)
+    assert @cache.exist?(8)
+    assert @cache.exist?(7)
+    assert !@cache.exist?(6), "no entry"
+    assert !@cache.exist?(5), "no entry"
+    assert @cache.exist?(4)
+    assert !@cache.exist?(3), "no entry"
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_prune_size_on_write_based_on_key_length
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.write(6, "ffffffffff") && sleep(0.001)
+    @cache.write(7, "gggggggggg") && sleep(0.001)
+    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
+    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
+    long_key = "*" * 2 * @record_size
+    @cache.write(long_key, "llllllllll")
+    assert @cache.exist?(long_key)
+    assert @cache.exist?(9)
+    assert @cache.exist?(8)
+    assert @cache.exist?(7)
+    assert @cache.exist?(6)
+    assert !@cache.exist?(5), "no entry"
+    assert !@cache.exist?(4), "no entry"
+    assert !@cache.exist?(3), "no entry"
+    assert !@cache.exist?(2), "no entry"
+    assert !@cache.exist?(1), "no entry"
+  end
+
+  def test_pruning_is_capped_at_a_max_time
+    def @cache.delete_entry(*args)
+      sleep(0.01)
+      super
+    end
+    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
+    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
+    @cache.write(3, "cccccccccc") && sleep(0.001)
+    @cache.write(4, "dddddddddd") && sleep(0.001)
+    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
+    @cache.prune(30, 0.001)
+    assert @cache.exist?(5)
+    assert @cache.exist?(4)
+    assert @cache.exist?(3)
+    assert @cache.exist?(2)
+    assert !@cache.exist?(1)
+  end
+
+  def test_write_with_unless_exist
+    assert_equal true, @cache.write(1, "aaaaaaaaaa")
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+    @cache.write(1, nil)
+    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
+  end
+end
diff --git a/activesupport/test/cache/stores/null_store_test.rb b/activesupport/test/cache/stores/null_store_test.rb
new file mode 100644
index 0000000000..0945aceee3
--- /dev/null
+++ b/activesupport/test/cache/stores/null_store_test.rb
@@ -0,0 +1,58 @@
+# frozen_string_literal: true
+require "abstract_unit"
+require "active_support/cache"
+require_relative "../behaviors"
+
+class NullStoreTest < ActiveSupport::TestCase
+  def setup
+    @cache = ActiveSupport::Cache.lookup_store(:null_store)
+  end
+
+  def test_clear
+    @cache.clear
+  end
+
+  def test_cleanup
+    @cache.cleanup
+  end
+
+  def test_write
+    assert_equal true, @cache.write("name", "value")
+  end
+
+  def test_read
+    @cache.write("name", "value")
+    assert_nil @cache.read("name")
+  end
+
+  def test_delete
+    @cache.write("name", "value")
+    assert_equal false, @cache.delete("name")
+  end
+
+  def test_increment
+    @cache.write("name", 1, raw: true)
+    assert_nil @cache.increment("name")
+  end
+
+  def test_decrement
+    @cache.write("name", 1, raw: true)
+    assert_nil @cache.increment("name")
+  end
+
+  def test_delete_matched
+    @cache.write("name", "value")
+    @cache.delete_matched(/name/)
+  end
+
+  def test_local_store_strategy
+    @cache.with_local_cache do
+      @cache.write("name", "value")
+      assert_equal "value", @cache.read("name")
+      @cache.delete("name")
+      assert_nil @cache.read("name")
+      @cache.write("name", "value")
+    end
+    assert_nil @cache.read("name")
+  end
+end
diff --git a/activesupport/test/caching_test.rb b/activesupport/test/caching_test.rb
deleted file mode 100644
index f53b98c73e..0000000000
--- a/activesupport/test/caching_test.rb
+++ /dev/null
@@ -1,1301 +0,0 @@
-require "logger"
-require "abstract_unit"
-require "active_support/cache"
-require "dependencies_test_helpers"
-
-require "pathname"
-
-module ActiveSupport
-  module Cache
-    module Strategy
-      module LocalCache
-        class MiddlewareTest < ActiveSupport::TestCase
-          def test_local_cache_cleared_on_close
-            key = "super awesome key"
-            assert_nil LocalCacheRegistry.cache_for key
-            middleware = Middleware.new("<3", key).new(->(env) {
-              assert LocalCacheRegistry.cache_for(key), "should have a cache"
-              [200, {}, []]
-            })
-            _, _, body = middleware.call({})
-            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
-            body.each {}
-            assert LocalCacheRegistry.cache_for(key), "should still have a cache"
-            body.close
-            assert_nil LocalCacheRegistry.cache_for(key)
-          end
-
-          def test_local_cache_cleared_and_response_should_be_present_on_invalid_parameters_error
-            key = "super awesome key"
-            assert_nil LocalCacheRegistry.cache_for key
-            middleware = Middleware.new("<3", key).new(->(env) {
-              assert LocalCacheRegistry.cache_for(key), "should have a cache"
-              raise Rack::Utils::InvalidParameterError
-            })
-            response = middleware.call({})
-            assert response, "response should exist"
-            assert_nil LocalCacheRegistry.cache_for(key)
-          end
-
-          def test_local_cache_cleared_on_exception
-            key = "super awesome key"
-            assert_nil LocalCacheRegistry.cache_for key
-            middleware = Middleware.new("<3", key).new(->(env) {
-              assert LocalCacheRegistry.cache_for(key), "should have a cache"
-              raise
-            })
-            assert_raises(RuntimeError) { middleware.call({}) }
-            assert_nil LocalCacheRegistry.cache_for(key)
-          end
-
-          def test_local_cache_cleared_on_throw
-            key = "super awesome key"
-            assert_nil LocalCacheRegistry.cache_for key
-            middleware = Middleware.new("<3", key).new(->(env) {
-              assert LocalCacheRegistry.cache_for(key), "should have a cache"
-              throw :warden
-            })
-            assert_throws(:warden) { middleware.call({}) }
-            assert_nil LocalCacheRegistry.cache_for(key)
-          end
-        end
-      end
-    end
-  end
-end
-
-class CacheKeyTest < ActiveSupport::TestCase
-  def test_entry_legacy_optional_ivars
-    legacy = Class.new(ActiveSupport::Cache::Entry) do
-      def initialize(value, options = {})
-        @value = value
-        @expires_in = nil
-        @created_at = nil
-        super
-      end
-    end
-
-    entry = legacy.new "foo"
-    assert_equal "foo", entry.value
-  end
-
-  def test_expand_cache_key
-    assert_equal "1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true])
-    assert_equal "name/1/2/true", ActiveSupport::Cache.expand_cache_key([1, "2", true], :name)
-  end
-
-  def test_expand_cache_key_with_rails_cache_id
-    with_env("RAILS_CACHE_ID" => "c99") do
-      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
-      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key([:foo])
-      assert_equal "c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar])
-      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key(:foo, :nm)
-      assert_equal "nm/c99/foo", ActiveSupport::Cache.expand_cache_key([:foo], :nm)
-      assert_equal "nm/c99/foo/bar", ActiveSupport::Cache.expand_cache_key([:foo, :bar], :nm)
-    end
-  end
-
-  def test_expand_cache_key_with_rails_app_version
-    with_env("RAILS_APP_VERSION" => "rails3") do
-      assert_equal "rails3/foo", ActiveSupport::Cache.expand_cache_key(:foo)
-    end
-  end
-
-  def test_expand_cache_key_rails_cache_id_should_win_over_rails_app_version
-    with_env("RAILS_CACHE_ID" => "c99", "RAILS_APP_VERSION" => "rails3") do
-      assert_equal "c99/foo", ActiveSupport::Cache.expand_cache_key(:foo)
-    end
-  end
-
-  def test_expand_cache_key_respond_to_cache_key
-    key = "foo"
-    def key.cache_key
-      :foo_key
-    end
-    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key(key)
-  end
-
-  def test_expand_cache_key_array_with_something_that_responds_to_cache_key
-    key = "foo"
-    def key.cache_key
-      :foo_key
-    end
-    assert_equal "foo_key", ActiveSupport::Cache.expand_cache_key([key])
-  end
-
-  def test_expand_cache_key_of_nil
-    assert_equal "", ActiveSupport::Cache.expand_cache_key(nil)
-  end
-
-  def test_expand_cache_key_of_false
-    assert_equal "false", ActiveSupport::Cache.expand_cache_key(false)
-  end
-
-  def test_expand_cache_key_of_true
-    assert_equal "true", ActiveSupport::Cache.expand_cache_key(true)
-  end
-
-  def test_expand_cache_key_of_array_like_object
-    assert_equal "foo/bar/baz", ActiveSupport::Cache.expand_cache_key(%w{foo bar baz}.to_enum)
-  end
-
-  private
-
-    def with_env(kv)
-      old_values = {}
-      kv.each { |key, value| old_values[key], ENV[key] = ENV[key], value }
-      yield
-    ensure
-      old_values.each { |key, value| ENV[key] = value }
-    end
-end
-
-class CacheStoreSettingTest < ActiveSupport::TestCase
-  def test_memory_store_gets_created_if_no_arguments_passed_to_lookup_store_method
-    store = ActiveSupport::Cache.lookup_store
-    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
-  end
-
-  def test_memory_store
-    store = ActiveSupport::Cache.lookup_store :memory_store
-    assert_kind_of(ActiveSupport::Cache::MemoryStore, store)
-  end
-
-  def test_file_fragment_cache_store
-    store = ActiveSupport::Cache.lookup_store :file_store, "/path/to/cache/directory"
-    assert_kind_of(ActiveSupport::Cache::FileStore, store)
-    assert_equal "/path/to/cache/directory", store.cache_path
-  end
-
-  def test_mem_cache_fragment_cache_store
-    assert_called_with(Dalli::Client, :new, [%w[localhost], {}]) do
-      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost"
-      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
-    end
-  end
-
-  def test_mem_cache_fragment_cache_store_with_given_mem_cache
-    mem_cache = Dalli::Client.new
-    assert_not_called(Dalli::Client, :new) do
-      store = ActiveSupport::Cache.lookup_store :mem_cache_store, mem_cache
-      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
-    end
-  end
-
-  def test_mem_cache_fragment_cache_store_with_not_dalli_client
-    assert_not_called(Dalli::Client, :new) do
-      memcache = Object.new
-      assert_raises(ArgumentError) do
-        ActiveSupport::Cache.lookup_store :mem_cache_store, memcache
-      end
-    end
-  end
-
-  def test_mem_cache_fragment_cache_store_with_multiple_servers
-    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], {}]) do
-      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1"
-      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
-    end
-  end
-
-  def test_mem_cache_fragment_cache_store_with_options
-    assert_called_with(Dalli::Client, :new, [%w[localhost 192.168.1.1], { timeout: 10 }]) do
-      store = ActiveSupport::Cache.lookup_store :mem_cache_store, "localhost", "192.168.1.1", namespace: "foo", timeout: 10
-      assert_kind_of(ActiveSupport::Cache::MemCacheStore, store)
-      assert_equal "foo", store.options[:namespace]
-    end
-  end
-
-  def test_object_assigned_fragment_cache_store
-    store = ActiveSupport::Cache.lookup_store ActiveSupport::Cache::FileStore.new("/path/to/cache/directory")
-    assert_kind_of(ActiveSupport::Cache::FileStore, store)
-    assert_equal "/path/to/cache/directory", store.cache_path
-  end
-end
-
-class CacheStoreNamespaceTest < ActiveSupport::TestCase
-  def test_static_namespace
-    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
-    cache.write("foo", "bar")
-    assert_equal "bar", cache.read("foo")
-    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
-  end
-
-  def test_proc_namespace
-    test_val = "tester"
-    proc = lambda { test_val }
-    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: proc)
-    cache.write("foo", "bar")
-    assert_equal "bar", cache.read("foo")
-    assert_equal "bar", cache.instance_variable_get(:@data)["tester:foo"].value
-  end
-
-  def test_delete_matched_key_start
-    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "tester")
-    cache.write("foo", "bar")
-    cache.write("fu", "baz")
-    cache.delete_matched(/^fo/)
-    assert !cache.exist?("foo")
-    assert cache.exist?("fu")
-  end
-
-  def test_delete_matched_key
-    cache = ActiveSupport::Cache.lookup_store(:memory_store, namespace: "foo")
-    cache.write("foo", "bar")
-    cache.write("fu", "baz")
-    cache.delete_matched(/OO/i)
-    assert !cache.exist?("foo")
-    assert cache.exist?("fu")
-  end
-end
-
-# Tests the base functionality that should be identical across all cache stores.
-module CacheStoreBehavior
-  def test_should_read_and_write_strings
-    assert @cache.write("foo", "bar")
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_should_overwrite
-    @cache.write("foo", "bar")
-    @cache.write("foo", "baz")
-    assert_equal "baz", @cache.read("foo")
-  end
-
-  def test_fetch_without_cache_miss
-    @cache.write("foo", "bar")
-    assert_not_called(@cache, :write) do
-      assert_equal "bar", @cache.fetch("foo") { "baz" }
-    end
-  end
-
-  def test_fetch_with_cache_miss
-    assert_called_with(@cache, :write, ["foo", "baz", @cache.options]) do
-      assert_equal "baz", @cache.fetch("foo") { "baz" }
-    end
-  end
-
-  def test_fetch_with_cache_miss_passes_key_to_block
-    cache_miss = false
-    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
-    assert cache_miss
-
-    cache_miss = false
-    assert_equal 3, @cache.fetch("foo") { |key| cache_miss = true; key.length }
-    assert !cache_miss
-  end
-
-  def test_fetch_with_forced_cache_miss
-    @cache.write("foo", "bar")
-    assert_not_called(@cache, :read) do
-      assert_called_with(@cache, :write, ["foo", "bar", @cache.options.merge(force: true)]) do
-        @cache.fetch("foo", force: true) { "bar" }
-      end
-    end
-  end
-
-  def test_fetch_with_cached_nil
-    @cache.write("foo", nil)
-    assert_not_called(@cache, :write) do
-      assert_nil @cache.fetch("foo") { "baz" }
-    end
-  end
-
-  def test_fetch_with_forced_cache_miss_with_block
-    @cache.write("foo", "bar")
-    assert_equal "foo_bar", @cache.fetch("foo", force: true) { "foo_bar" }
-  end
-
-  def test_fetch_with_forced_cache_miss_without_block
-    @cache.write("foo", "bar")
-    assert_raises(ArgumentError) do
-      @cache.fetch("foo", force: true)
-    end
-
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_should_read_and_write_hash
-    assert @cache.write("foo", a: "b")
-    assert_equal({ a: "b" }, @cache.read("foo"))
-  end
-
-  def test_should_read_and_write_integer
-    assert @cache.write("foo", 1)
-    assert_equal 1, @cache.read("foo")
-  end
-
-  def test_should_read_and_write_nil
-    assert @cache.write("foo", nil)
-    assert_nil @cache.read("foo")
-  end
-
-  def test_should_read_and_write_false
-    assert @cache.write("foo", false)
-    assert_equal false, @cache.read("foo")
-  end
-
-  def test_read_multi
-    @cache.write("foo", "bar")
-    @cache.write("fu", "baz")
-    @cache.write("fud", "biz")
-    assert_equal({ "foo" => "bar", "fu" => "baz" }, @cache.read_multi("foo", "fu"))
-  end
-
-  def test_read_multi_with_expires
-    time = Time.now
-    @cache.write("foo", "bar", expires_in: 10)
-    @cache.write("fu", "baz")
-    @cache.write("fud", "biz")
-    Time.stub(:now, time + 11) do
-      assert_equal({ "fu" => "baz" }, @cache.read_multi("foo", "fu"))
-    end
-  end
-
-  def test_fetch_multi
-    @cache.write("foo", "bar")
-    @cache.write("fud", "biz")
-
-    values = @cache.fetch_multi("foo", "fu", "fud") { |value| value * 2 }
-
-    assert_equal({ "foo" => "bar", "fu" => "fufu", "fud" => "biz" }, values)
-    assert_equal("fufu", @cache.read("fu"))
-  end
-
-  def test_multi_with_objects
-    cache_struct = Struct.new(:cache_key, :title)
-    foo = cache_struct.new("foo", "FOO!")
-    bar = cache_struct.new("bar")
-
-    @cache.write("bar", "BAM!")
-
-    values = @cache.fetch_multi(foo, bar) { |object| object.title }
-
-    assert_equal({ foo => "FOO!", bar => "BAM!" }, values)
-  end
-
-  def test_fetch_multi_without_block
-    assert_raises(ArgumentError) do
-      @cache.fetch_multi("foo")
-    end
-  end
-
-  def test_read_and_write_compressed_small_data
-    @cache.write("foo", "bar", compress: true)
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_read_and_write_compressed_large_data
-    @cache.write("foo", "bar", compress: true, compress_threshold: 2)
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_read_and_write_compressed_nil
-    @cache.write("foo", nil, compress: true)
-    assert_nil @cache.read("foo")
-  end
-
-  def test_cache_key
-    obj = Object.new
-    def obj.cache_key
-      :foo
-    end
-    @cache.write(obj, "bar")
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_param_as_cache_key
-    obj = Object.new
-    def obj.to_param
-      "foo"
-    end
-    @cache.write(obj, "bar")
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_array_as_cache_key
-    @cache.write([:fu, "foo"], "bar")
-    assert_equal "bar", @cache.read("fu/foo")
-  end
-
-  def test_hash_as_cache_key
-    @cache.write({ foo: 1, fu: 2 }, "bar")
-    assert_equal "bar", @cache.read("foo=1/fu=2")
-  end
-
-  def test_keys_are_case_sensitive
-    @cache.write("foo", "bar")
-    assert_nil @cache.read("FOO")
-  end
-
-  def test_exist
-    @cache.write("foo", "bar")
-    assert_equal true, @cache.exist?("foo")
-    assert_equal false, @cache.exist?("bar")
-  end
-
-  def test_nil_exist
-    @cache.write("foo", nil)
-    assert @cache.exist?("foo")
-  end
-
-  def test_delete
-    @cache.write("foo", "bar")
-    assert @cache.exist?("foo")
-    assert @cache.delete("foo")
-    assert !@cache.exist?("foo")
-  end
-
-  def test_original_store_objects_should_not_be_immutable
-    bar = "bar"
-    @cache.write("foo", bar)
-    assert_nothing_raised { bar.gsub!(/.*/, "baz") }
-  end
-
-  def test_expires_in
-    time = Time.local(2008, 4, 24)
-
-    Time.stub(:now, time) do
-      @cache.write("foo", "bar")
-      assert_equal "bar", @cache.read("foo")
-    end
-
-    Time.stub(:now, time + 30) do
-      assert_equal "bar", @cache.read("foo")
-    end
-
-    Time.stub(:now, time + 61) do
-      assert_nil @cache.read("foo")
-    end
-  end
-
-  def test_race_condition_protection_skipped_if_not_defined
-    @cache.write("foo", "bar")
-    time = @cache.send(:read_entry, @cache.send(:normalize_key, "foo", {}), {}).expires_at
-
-    Time.stub(:now, Time.at(time)) do
-      result = @cache.fetch("foo") do
-        assert_nil @cache.read("foo")
-        "baz"
-      end
-      assert_equal "baz", result
-    end
-  end
-
-  def test_race_condition_protection_is_limited
-    time = Time.now
-    @cache.write("foo", "bar", expires_in: 60)
-    Time.stub(:now, time + 71) do
-      result = @cache.fetch("foo", race_condition_ttl: 10) do
-        assert_nil @cache.read("foo")
-        "baz"
-      end
-      assert_equal "baz", result
-    end
-  end
-
-  def test_race_condition_protection_is_safe
-    time = Time.now
-    @cache.write("foo", "bar", expires_in: 60)
-    Time.stub(:now, time + 61) do
-      begin
-        @cache.fetch("foo", race_condition_ttl: 10) do
-          assert_equal "bar", @cache.read("foo")
-          raise ArgumentError.new
-        end
-      rescue ArgumentError
-      end
-      assert_equal "bar", @cache.read("foo")
-    end
-    Time.stub(:now, time + 91) do
-      assert_nil @cache.read("foo")
-    end
-  end
-
-  def test_race_condition_protection
-    time = Time.now
-    @cache.write("foo", "bar", expires_in: 60)
-    Time.stub(:now, time + 61) do
-      result = @cache.fetch("foo", race_condition_ttl: 10) do
-        assert_equal "bar", @cache.read("foo")
-        "baz"
-      end
-      assert_equal "baz", result
-    end
-  end
-
-  def test_crazy_key_characters
-    crazy_key = "#/:*(<+=> )&$%@?;'\"\'`~-"
-    assert @cache.write(crazy_key, "1", raw: true)
-    assert_equal "1", @cache.read(crazy_key)
-    assert_equal "1", @cache.fetch(crazy_key)
-    assert @cache.delete(crazy_key)
-    assert_equal "2", @cache.fetch(crazy_key, raw: true) { "2" }
-    assert_equal 3, @cache.increment(crazy_key)
-    assert_equal 2, @cache.decrement(crazy_key)
-  end
-
-  def test_really_long_keys
-    key = ""
-    900.times { key << "x" }
-    assert @cache.write(key, "bar")
-    assert_equal "bar", @cache.read(key)
-    assert_equal "bar", @cache.fetch(key)
-    assert_nil @cache.read("#{key}x")
-    assert_equal({ key => "bar" }, @cache.read_multi(key))
-    assert @cache.delete(key)
-  end
-
-  def test_cache_hit_instrumentation
-    key = "test_key"
-    @events = []
-    ActiveSupport::Notifications.subscribe "cache_read.active_support" do |*args|
-      @events << ActiveSupport::Notifications::Event.new(*args)
-    end
-    assert @cache.write(key, "1", raw: true)
-    assert @cache.fetch(key) {}
-    assert_equal 1, @events.length
-    assert_equal "cache_read.active_support", @events[0].name
-    assert_equal :fetch, @events[0].payload[:super_operation]
-    assert @events[0].payload[:hit]
-  ensure
-    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
-  end
-
-  def test_cache_miss_instrumentation
-    @events = []
-    ActiveSupport::Notifications.subscribe(/^cache_(.*)\.active_support$/) do |*args|
-      @events << ActiveSupport::Notifications::Event.new(*args)
-    end
-    assert_not @cache.fetch("bad_key") {}
-    assert_equal 3, @events.length
-    assert_equal "cache_read.active_support", @events[0].name
-    assert_equal "cache_generate.active_support", @events[1].name
-    assert_equal "cache_write.active_support", @events[2].name
-    assert_equal :fetch, @events[0].payload[:super_operation]
-    assert_not @events[0].payload[:hit]
-  ensure
-    ActiveSupport::Notifications.unsubscribe "cache_read.active_support"
-  end
-end
-
-module CacheStoreVersionBehavior
-  ModelWithKeyAndVersion = Struct.new(:cache_key, :cache_version)
-
-  def test_fetch_with_right_version_should_hit
-    @cache.fetch("foo", version: 1) { "bar" }
-    assert_equal "bar", @cache.read("foo", version: 1)
-  end
-
-  def test_fetch_with_wrong_version_should_miss
-    @cache.fetch("foo", version: 1) { "bar" }
-    assert_nil @cache.read("foo", version: 2)
-  end
-
-  def test_read_with_right_version_should_hit
-    @cache.write("foo", "bar", version: 1)
-    assert_equal "bar", @cache.read("foo", version: 1)
-  end
-
-  def test_read_with_wrong_version_should_miss
-    @cache.write("foo", "bar", version: 1)
-    assert_nil @cache.read("foo", version: 2)
-  end
-
-  def test_exist_with_right_version_should_be_true
-    @cache.write("foo", "bar", version: 1)
-    assert @cache.exist?("foo", version: 1)
-  end
-
-  def test_exist_with_wrong_version_should_be_false
-    @cache.write("foo", "bar", version: 1)
-    assert !@cache.exist?("foo", version: 2)
-  end
-
-  def test_reading_and_writing_with_model_supporting_cache_version
-    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
-    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
-
-    @cache.write(m1v1, "bar")
-    assert_equal "bar", @cache.read(m1v1)
-    assert_nil @cache.read(m1v2)
-  end
-
-  def test_reading_and_writing_with_model_supporting_cache_version_using_nested_key
-    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
-    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
-
-    @cache.write([ "something", m1v1 ], "bar")
-    assert_equal "bar", @cache.read([ "something", m1v1 ])
-    assert_nil @cache.read([ "something", m1v2 ])
-  end
-
-  def test_fetching_with_model_supporting_cache_version
-    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
-    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
-
-    @cache.fetch(m1v1) { "bar" }
-    assert_equal "bar", @cache.fetch(m1v1) { "bu" }
-    assert_equal "bu", @cache.fetch(m1v2) { "bu" }
-  end
-
-  def test_exist_with_model_supporting_cache_version
-    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
-    m1v2 = ModelWithKeyAndVersion.new("model/1", 2)
-
-    @cache.write(m1v1, "bar")
-    assert     @cache.exist?(m1v1)
-    assert_not @cache.fetch(m1v2)
-  end
-
-  def test_fetch_multi_with_model_supporting_cache_version
-    m1v1 = ModelWithKeyAndVersion.new("model/1", 1)
-    m2v1 = ModelWithKeyAndVersion.new("model/2", 1)
-    m2v2 = ModelWithKeyAndVersion.new("model/2", 2)
-
-    first_fetch_values  = @cache.fetch_multi(m1v1, m2v1) { |m| m.cache_key }
-    second_fetch_values = @cache.fetch_multi(m1v1, m2v2) { |m| m.cache_key + " 2nd" }
-
-    assert_equal({ m1v1 => "model/1", m2v1 => "model/2" }, first_fetch_values)
-    assert_equal({ m1v1 => "model/1", m2v2 => "model/2 2nd" }, second_fetch_values)
-  end
-
-  def test_version_is_normalized
-    @cache.write("foo", "bar", version: 1)
-    assert_equal "bar", @cache.read("foo", version: "1")
-  end
-end
-
-# https://rails.lighthouseapp.com/projects/8994/tickets/6225-memcachestore-cant-deal-with-umlauts-and-special-characters
-# The error is caused by character encodings that can't be compared with ASCII-8BIT regular expressions and by special
-# characters like the umlaut in UTF-8.
-module EncodedKeyCacheBehavior
-  Encoding.list.each do |encoding|
-    define_method "test_#{encoding.name.underscore}_encoded_values" do
-      key = "foo".force_encoding(encoding)
-      assert @cache.write(key, "1", raw: true)
-      assert_equal "1", @cache.read(key)
-      assert_equal "1", @cache.fetch(key)
-      assert @cache.delete(key)
-      assert_equal "2", @cache.fetch(key, raw: true) { "2" }
-      assert_equal 3, @cache.increment(key)
-      assert_equal 2, @cache.decrement(key)
-    end
-  end
-
-  def test_common_utf8_values
-    key = "\xC3\xBCmlaut".force_encoding(Encoding::UTF_8)
-    assert @cache.write(key, "1", raw: true)
-    assert_equal "1", @cache.read(key)
-    assert_equal "1", @cache.fetch(key)
-    assert @cache.delete(key)
-    assert_equal "2", @cache.fetch(key, raw: true) { "2" }
-    assert_equal 3, @cache.increment(key)
-    assert_equal 2, @cache.decrement(key)
-  end
-
-  def test_retains_encoding
-    key = "\xC3\xBCmlaut".force_encoding(Encoding::UTF_8)
-    assert @cache.write(key, "1", raw: true)
-    assert_equal Encoding::UTF_8, key.encoding
-  end
-end
-
-module CacheDeleteMatchedBehavior
-  def test_delete_matched
-    @cache.write("foo", "bar")
-    @cache.write("fu", "baz")
-    @cache.write("foo/bar", "baz")
-    @cache.write("fu/baz", "bar")
-    @cache.delete_matched(/oo/)
-    assert !@cache.exist?("foo")
-    assert @cache.exist?("fu")
-    assert !@cache.exist?("foo/bar")
-    assert @cache.exist?("fu/baz")
-  end
-end
-
-module CacheIncrementDecrementBehavior
-  def test_increment
-    @cache.write("foo", 1, raw: true)
-    assert_equal 1, @cache.read("foo").to_i
-    assert_equal 2, @cache.increment("foo")
-    assert_equal 2, @cache.read("foo").to_i
-    assert_equal 3, @cache.increment("foo")
-    assert_equal 3, @cache.read("foo").to_i
-    assert_nil @cache.increment("bar")
-  end
-
-  def test_decrement
-    @cache.write("foo", 3, raw: true)
-    assert_equal 3, @cache.read("foo").to_i
-    assert_equal 2, @cache.decrement("foo")
-    assert_equal 2, @cache.read("foo").to_i
-    assert_equal 1, @cache.decrement("foo")
-    assert_equal 1, @cache.read("foo").to_i
-    assert_nil @cache.decrement("bar")
-  end
-end
-
-module LocalCacheBehavior
-  def test_local_writes_are_persistent_on_the_remote_cache
-    retval = @cache.with_local_cache do
-      @cache.write("foo", "bar")
-    end
-    assert retval
-    assert_equal "bar", @cache.read("foo")
-  end
-
-  def test_clear_also_clears_local_cache
-    @cache.with_local_cache do
-      @cache.write("foo", "bar")
-      @cache.clear
-      assert_nil @cache.read("foo")
-    end
-
-    assert_nil @cache.read("foo")
-  end
-
-  def test_local_cache_of_write
-    @cache.with_local_cache do
-      @cache.write("foo", "bar")
-      @peek.delete("foo")
-      assert_equal "bar", @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_read
-    @cache.write("foo", "bar")
-    @cache.with_local_cache do
-      assert_equal "bar", @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_read_nil
-    @cache.with_local_cache do
-      assert_nil @cache.read("foo")
-      @cache.send(:bypass_local_cache) { @cache.write "foo", "bar" }
-      assert_nil @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_fetch
-    @cache.with_local_cache do
-      @cache.send(:local_cache).write "foo", "bar"
-      assert_equal "bar", @cache.send(:local_cache).fetch("foo")
-    end
-  end
-
-  def test_local_cache_of_write_nil
-    @cache.with_local_cache do
-      assert @cache.write("foo", nil)
-      assert_nil @cache.read("foo")
-      @peek.write("foo", "bar")
-      assert_nil @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_write_with_unless_exist
-    @cache.with_local_cache do
-      @cache.write("foo", "bar")
-      @cache.write("foo", "baz", unless_exist: true)
-      assert_equal @peek.read("foo"), @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_delete
-    @cache.with_local_cache do
-      @cache.write("foo", "bar")
-      @cache.delete("foo")
-      assert_nil @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_exist
-    @cache.with_local_cache do
-      @cache.write("foo", "bar")
-      @peek.delete("foo")
-      assert @cache.exist?("foo")
-    end
-  end
-
-  def test_local_cache_of_increment
-    @cache.with_local_cache do
-      @cache.write("foo", 1, raw: true)
-      @peek.write("foo", 2, raw: true)
-      @cache.increment("foo")
-      assert_equal 3, @cache.read("foo")
-    end
-  end
-
-  def test_local_cache_of_decrement
-    @cache.with_local_cache do
-      @cache.write("foo", 1, raw: true)
-      @peek.write("foo", 3, raw: true)
-      @cache.decrement("foo")
-      assert_equal 2, @cache.read("foo")
-    end
-  end
-
-  def test_middleware
-    app = lambda { |env|
-      result = @cache.write("foo", "bar")
-      assert_equal "bar", @cache.read("foo") # make sure 'foo' was written
-      assert result
-      [200, {}, []]
-    }
-    app = @cache.middleware.new(app)
-    app.call({})
-  end
-end
-
-module AutoloadingCacheBehavior
-  include DependenciesTestHelpers
-  def test_simple_autoloading
-    with_autoloading_fixtures do
-      @cache.write("foo", EM.new)
-    end
-
-    remove_constants(:EM)
-    ActiveSupport::Dependencies.clear
-
-    with_autoloading_fixtures do
-      assert_kind_of EM, @cache.read("foo")
-    end
-
-    remove_constants(:EM)
-    ActiveSupport::Dependencies.clear
-  end
-
-  def test_two_classes_autoloading
-    with_autoloading_fixtures do
-      @cache.write("foo", [EM.new, ClassFolder.new])
-    end
-
-    remove_constants(:EM, :ClassFolder)
-    ActiveSupport::Dependencies.clear
-
-    with_autoloading_fixtures do
-      loaded = @cache.read("foo")
-      assert_kind_of Array, loaded
-      assert_equal 2, loaded.size
-      assert_kind_of EM, loaded[0]
-      assert_kind_of ClassFolder, loaded[1]
-    end
-
-    remove_constants(:EM, :ClassFolder)
-    ActiveSupport::Dependencies.clear
-  end
-end
-
-class FileStoreTest < ActiveSupport::TestCase
-  def setup
-    Dir.mkdir(cache_dir) unless File.exist?(cache_dir)
-    @cache = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
-    @peek = ActiveSupport::Cache.lookup_store(:file_store, cache_dir, expires_in: 60)
-    @cache_with_pathname = ActiveSupport::Cache.lookup_store(:file_store, Pathname.new(cache_dir), expires_in: 60)
-
-    @buffer = StringIO.new
-    @cache.logger = ActiveSupport::Logger.new(@buffer)
-  end
-
-  def teardown
-    FileUtils.rm_r(cache_dir)
-  rescue Errno::ENOENT
-  end
-
-  def cache_dir
-    File.join(Dir.pwd, "tmp_cache")
-  end
-
-  include CacheStoreBehavior
-  include CacheStoreVersionBehavior
-  include LocalCacheBehavior
-  include CacheDeleteMatchedBehavior
-  include CacheIncrementDecrementBehavior
-  include AutoloadingCacheBehavior
-
-  def test_clear
-    gitkeep = File.join(cache_dir, ".gitkeep")
-    keep = File.join(cache_dir, ".keep")
-    FileUtils.touch([gitkeep, keep])
-    @cache.clear
-    assert File.exist?(gitkeep)
-    assert File.exist?(keep)
-  end
-
-  def test_clear_without_cache_dir
-    FileUtils.rm_r(cache_dir)
-    @cache.clear
-  end
-
-  def test_long_uri_encoded_keys
-    @cache.write("%" * 870, 1)
-    assert_equal 1, @cache.read("%" * 870)
-  end
-
-  def test_key_transformation
-    key = @cache.send(:normalize_key, "views/index?id=1", {})
-    assert_equal "views/index?id=1", @cache.send(:file_path_key, key)
-  end
-
-  def test_key_transformation_with_pathname
-    FileUtils.touch(File.join(cache_dir, "foo"))
-    key = @cache_with_pathname.send(:normalize_key, "views/index?id=1", {})
-    assert_equal "views/index?id=1", @cache_with_pathname.send(:file_path_key, key)
-  end
-
-  # Test that generated cache keys are short enough to have Tempfile stuff added to them and
-  # remain valid
-  def test_filename_max_size
-    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}"
-    path = @cache.send(:normalize_key, key, {})
-    Dir::Tmpname.create(path) do |tmpname, n, opts|
-      assert File.basename(tmpname + ".lock").length <= 255, "Temp filename too long: #{File.basename(tmpname + '.lock').length}"
-    end
-  end
-
-  # Because file systems have a maximum filename size, filenames > max size should be split in to directories
-  # If filename is 'AAAAB', where max size is 4, the returned path should be AAAA/B
-  def test_key_transformation_max_filename_size
-    key = "#{'A' * ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE}B"
-    path = @cache.send(:normalize_key, key, {})
-    assert path.split("/").all? { |dir_name| dir_name.size <= ActiveSupport::Cache::FileStore::FILENAME_MAX_SIZE }
-    assert_equal "B", File.basename(path)
-  end
-
-  # If nothing has been stored in the cache, there is a chance the cache directory does not yet exist
-  # Ensure delete_matched gracefully handles this case
-  def test_delete_matched_when_cache_directory_does_not_exist
-    assert_nothing_raised do
-      ActiveSupport::Cache::FileStore.new("/test/cache/directory").delete_matched(/does_not_exist/)
-    end
-  end
-
-  def test_delete_does_not_delete_empty_parent_dir
-    sub_cache_dir = File.join(cache_dir, "subdir/")
-    sub_cache_store = ActiveSupport::Cache::FileStore.new(sub_cache_dir)
-    assert_nothing_raised do
-      assert sub_cache_store.write("foo", "bar")
-      assert sub_cache_store.delete("foo")
-    end
-    assert File.exist?(cache_dir), "Parent of top level cache dir was deleted!"
-    assert File.exist?(sub_cache_dir), "Top level cache dir was deleted!"
-    assert Dir.entries(sub_cache_dir).reject { |f| ActiveSupport::Cache::FileStore::EXCLUDED_DIRS.include?(f) }.empty?
-  end
-
-  def test_log_exception_when_cache_read_fails
-    File.stub(:exist?, -> { raise StandardError.new("failed") }) do
-      @cache.send(:read_entry, "winston", {})
-      assert @buffer.string.present?
-    end
-  end
-
-  def test_cleanup_removes_all_expired_entries
-    time = Time.now
-    @cache.write("foo", "bar", expires_in: 10)
-    @cache.write("baz", "qux")
-    @cache.write("quux", "corge", expires_in: 20)
-    Time.stub(:now, time + 15) do
-      @cache.cleanup
-      assert_not @cache.exist?("foo")
-      assert @cache.exist?("baz")
-      assert @cache.exist?("quux")
-    end
-  end
-
-  def test_write_with_unless_exist
-    assert_equal true, @cache.write(1, "aaaaaaaaaa")
-    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
-    @cache.write(1, nil)
-    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
-  end
-end
-
-class MemoryStoreTest < ActiveSupport::TestCase
-  def setup
-    @record_size = ActiveSupport::Cache.lookup_store(:memory_store).send(:cached_size, 1, ActiveSupport::Cache::Entry.new("aaaaaaaaaa"))
-    @cache = ActiveSupport::Cache.lookup_store(:memory_store, expires_in: 60, size: @record_size * 10 + 1)
-  end
-
-  include CacheStoreBehavior
-  include CacheStoreVersionBehavior
-  include CacheDeleteMatchedBehavior
-  include CacheIncrementDecrementBehavior
-
-  def test_prune_size
-    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
-    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
-    @cache.write(3, "cccccccccc") && sleep(0.001)
-    @cache.write(4, "dddddddddd") && sleep(0.001)
-    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
-    @cache.read(2) && sleep(0.001)
-    @cache.read(4)
-    @cache.prune(@record_size * 3)
-    assert @cache.exist?(5)
-    assert @cache.exist?(4)
-    assert !@cache.exist?(3), "no entry"
-    assert @cache.exist?(2)
-    assert !@cache.exist?(1), "no entry"
-  end
-
-  def test_prune_size_on_write
-    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
-    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
-    @cache.write(3, "cccccccccc") && sleep(0.001)
-    @cache.write(4, "dddddddddd") && sleep(0.001)
-    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
-    @cache.write(6, "ffffffffff") && sleep(0.001)
-    @cache.write(7, "gggggggggg") && sleep(0.001)
-    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
-    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
-    @cache.write(10, "kkkkkkkkkk") && sleep(0.001)
-    @cache.read(2) && sleep(0.001)
-    @cache.read(4) && sleep(0.001)
-    @cache.write(11, "llllllllll")
-    assert @cache.exist?(11)
-    assert @cache.exist?(10)
-    assert @cache.exist?(9)
-    assert @cache.exist?(8)
-    assert @cache.exist?(7)
-    assert !@cache.exist?(6), "no entry"
-    assert !@cache.exist?(5), "no entry"
-    assert @cache.exist?(4)
-    assert !@cache.exist?(3), "no entry"
-    assert @cache.exist?(2)
-    assert !@cache.exist?(1), "no entry"
-  end
-
-  def test_prune_size_on_write_based_on_key_length
-    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
-    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
-    @cache.write(3, "cccccccccc") && sleep(0.001)
-    @cache.write(4, "dddddddddd") && sleep(0.001)
-    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
-    @cache.write(6, "ffffffffff") && sleep(0.001)
-    @cache.write(7, "gggggggggg") && sleep(0.001)
-    @cache.write(8, "hhhhhhhhhh") && sleep(0.001)
-    @cache.write(9, "iiiiiiiiii") && sleep(0.001)
-    long_key = "*" * 2 * @record_size
-    @cache.write(long_key, "llllllllll")
-    assert @cache.exist?(long_key)
-    assert @cache.exist?(9)
-    assert @cache.exist?(8)
-    assert @cache.exist?(7)
-    assert @cache.exist?(6)
-    assert !@cache.exist?(5), "no entry"
-    assert !@cache.exist?(4), "no entry"
-    assert !@cache.exist?(3), "no entry"
-    assert !@cache.exist?(2), "no entry"
-    assert !@cache.exist?(1), "no entry"
-  end
-
-  def test_pruning_is_capped_at_a_max_time
-    def @cache.delete_entry(*args)
-      sleep(0.01)
-      super
-    end
-    @cache.write(1, "aaaaaaaaaa") && sleep(0.001)
-    @cache.write(2, "bbbbbbbbbb") && sleep(0.001)
-    @cache.write(3, "cccccccccc") && sleep(0.001)
-    @cache.write(4, "dddddddddd") && sleep(0.001)
-    @cache.write(5, "eeeeeeeeee") && sleep(0.001)
-    @cache.prune(30, 0.001)
-    assert @cache.exist?(5)
-    assert @cache.exist?(4)
-    assert @cache.exist?(3)
-    assert @cache.exist?(2)
-    assert !@cache.exist?(1)
-  end
-
-  def test_write_with_unless_exist
-    assert_equal true, @cache.write(1, "aaaaaaaaaa")
-    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
-    @cache.write(1, nil)
-    assert_equal false, @cache.write(1, "aaaaaaaaaa", unless_exist: true)
-  end
-end
-
-class MemCacheStoreTest < ActiveSupport::TestCase
-  require "dalli"
-
-  begin
-    ss = Dalli::Client.new("localhost:11211").stats
-    raise Dalli::DalliError unless ss["localhost:11211"]
-
-    MEMCACHE_UP = true
-  rescue Dalli::DalliError
-    $stderr.puts "Skipping memcached tests. Start memcached and try again."
-    MEMCACHE_UP = false
-  end
-
-  def setup
-    skip "memcache server is not up" unless MEMCACHE_UP
-
-    @cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, expires_in: 60)
-    @peek = ActiveSupport::Cache.lookup_store(:mem_cache_store)
-    @data = @cache.instance_variable_get(:@data)
-    @cache.clear
-    @cache.silence!
-    @cache.logger = ActiveSupport::Logger.new("/dev/null")
-  end
-
-  include CacheStoreBehavior
-  include CacheStoreVersionBehavior
-  include LocalCacheBehavior
-  include CacheIncrementDecrementBehavior
-  include EncodedKeyCacheBehavior
-  include AutoloadingCacheBehavior
-
-  def test_raw_values
-    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
-    cache.clear
-    cache.write("foo", 2)
-    assert_equal "2", cache.read("foo")
-  end
-
-  def test_raw_values_with_marshal
-    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
-    cache.clear
-    cache.write("foo", Marshal.dump([]))
-    assert_equal [], cache.read("foo")
-  end
-
-  def test_local_cache_raw_values
-    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
-    cache.clear
-    cache.with_local_cache do
-      cache.write("foo", 2)
-      assert_equal "2", cache.read("foo")
-    end
-  end
-
-  def test_local_cache_raw_values_with_marshal
-    cache = ActiveSupport::Cache.lookup_store(:mem_cache_store, raw: true)
-    cache.clear
-    cache.with_local_cache do
-      cache.write("foo", Marshal.dump([]))
-      assert_equal [], cache.read("foo")
-    end
-  end
-
-  def test_read_should_return_a_different_object_id_each_time_it_is_called
-    @cache.write("foo", "bar")
-    value = @cache.read("foo")
-    assert_not_equal value.object_id, @cache.read("foo").object_id
-    value << "bingo"
-    assert_not_equal value, @cache.read("foo")
-  end
-end
-
-class NullStoreTest < ActiveSupport::TestCase
-  def setup
-    @cache = ActiveSupport::Cache.lookup_store(:null_store)
-  end
-
-  def test_clear
-    @cache.clear
-  end
-
-  def test_cleanup
-    @cache.cleanup
-  end
-
-  def test_write
-    assert_equal true, @cache.write("name", "value")
-  end
-
-  def test_read
-    @cache.write("name", "value")
-    assert_nil @cache.read("name")
-  end
-
-  def test_delete
-    @cache.write("name", "value")
-    assert_equal false, @cache.delete("name")
-  end
-
-  def test_increment
-    @cache.write("name", 1, raw: true)
-    assert_nil @cache.increment("name")
-  end
-
-  def test_decrement
-    @cache.write("name", 1, raw: true)
-    assert_nil @cache.increment("name")
-  end
-
-  def test_delete_matched
-    @cache.write("name", "value")
-    @cache.delete_matched(/name/)
-  end
-
-  def test_local_store_strategy
-    @cache.with_local_cache do
-      @cache.write("name", "value")
-      assert_equal "value", @cache.read("name")
-      @cache.delete("name")
-      assert_nil @cache.read("name")
-      @cache.write("name", "value")
-    end
-    assert_nil @cache.read("name")
-  end
-end
-
-class CacheStoreLoggerTest < ActiveSupport::TestCase
-  def setup
-    @cache = ActiveSupport::Cache.lookup_store(:memory_store)
-
-    @buffer = StringIO.new
-    @cache.logger = ActiveSupport::Logger.new(@buffer)
-  end
-
-  def test_logging
-    @cache.fetch("foo") { "bar" }
-    assert @buffer.string.present?
-  end
-
-  def test_log_with_string_namespace
-    @cache.fetch("foo", namespace: "string_namespace") { "bar" }
-    assert_match %r{string_namespace:foo}, @buffer.string
-  end
-
-  def test_log_with_proc_namespace
-    proc = Proc.new do
-      "proc_namespace"
-    end
-    @cache.fetch("foo", namespace: proc) { "bar" }
-    assert_match %r{proc_namespace:foo}, @buffer.string
-  end
-
-  def test_mute_logging
-    @cache.mute { @cache.fetch("foo") { "bar" } }
-    assert @buffer.string.blank?
-  end
-end
-
-class CacheEntryTest < ActiveSupport::TestCase
-  def test_expired
-    entry = ActiveSupport::Cache::Entry.new("value")
-    assert !entry.expired?, "entry not expired"
-    entry = ActiveSupport::Cache::Entry.new("value", expires_in: 60)
-    assert !entry.expired?, "entry not expired"
-    Time.stub(:now, Time.now + 61) do
-      assert entry.expired?, "entry is expired"
-    end
-  end
-
-  def test_compress_values
-    value = "value" * 100
-    entry = ActiveSupport::Cache::Entry.new(value, compress: true, compress_threshold: 1)
-    assert_equal value, entry.value
-    assert(value.bytesize > entry.size, "value is compressed")
-  end
-
-  def test_non_compress_values
-    value = "value" * 100
-    entry = ActiveSupport::Cache::Entry.new(value)
-    assert_equal value, entry.value
-    assert_equal value.bytesize, entry.size
-  end
-end
diff --git a/activesupport/test/callback_inheritance_test.rb b/activesupport/test/callback_inheritance_test.rb
index 9e2f7527e0..8872a16282 100644
--- a/activesupport/test/callback_inheritance_test.rb
+++ b/activesupport/test/callback_inheritance_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class GrandParent
diff --git a/activesupport/test/callbacks_test.rb b/activesupport/test/callbacks_test.rb
index 4f00afb581..9d924cabb2 100644
--- a/activesupport/test/callbacks_test.rb
+++ b/activesupport/test/callbacks_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 module CallbacksTest
diff --git a/activesupport/test/class_cache_test.rb b/activesupport/test/class_cache_test.rb
index 004b4dc9ce..b3ca3748c2 100644
--- a/activesupport/test/class_cache_test.rb
+++ b/activesupport/test/class_cache_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/dependencies"
 
diff --git a/activesupport/test/clean_backtrace_test.rb b/activesupport/test/clean_backtrace_test.rb
index 5ed518cdb0..7bbc54dfcc 100644
--- a/activesupport/test/clean_backtrace_test.rb
+++ b/activesupport/test/clean_backtrace_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class BacktraceCleanerFilterTest < ActiveSupport::TestCase
diff --git a/activesupport/test/clean_logger_test.rb b/activesupport/test/clean_logger_test.rb
index cf37fc5639..923a1cb671 100644
--- a/activesupport/test/clean_logger_test.rb
+++ b/activesupport/test/clean_logger_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "stringio"
 require "active_support/logger"
diff --git a/activesupport/test/concern_test.rb b/activesupport/test/concern_test.rb
index 7a5a5414a7..e05704393d 100644
--- a/activesupport/test/concern_test.rb
+++ b/activesupport/test/concern_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/concern"
 
diff --git a/activesupport/test/configurable_test.rb b/activesupport/test/configurable_test.rb
index 3cd6d2d4d0..bd3452334a 100644
--- a/activesupport/test/configurable_test.rb
+++ b/activesupport/test/configurable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/configurable"
 
diff --git a/activesupport/test/constantize_test_cases.rb b/activesupport/test/constantize_test_cases.rb
index 32b720bcbb..fa23fd6b65 100644
--- a/activesupport/test/constantize_test_cases.rb
+++ b/activesupport/test/constantize_test_cases.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "dependencies_test_helpers"
 
 module Ace
diff --git a/activesupport/test/core_ext/array/access_test.rb b/activesupport/test/core_ext/array/access_test.rb
index a38ea36d00..08af9e1b55 100644
--- a/activesupport/test/core_ext/array/access_test.rb
+++ b/activesupport/test/core_ext/array/access_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 
diff --git a/activesupport/test/core_ext/array/conversions_test.rb b/activesupport/test/core_ext/array/conversions_test.rb
index 29e661a99b..5a073344d9 100644
--- a/activesupport/test/core_ext/array/conversions_test.rb
+++ b/activesupport/test/core_ext/array/conversions_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 require "active_support/core_ext/big_decimal"
@@ -58,7 +59,7 @@ class ToSentenceTest < ActiveSupport::TestCase
       ["one", "two"].to_sentence(passing: "invalid option")
     end
 
-    assert_equal exception.message, "Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale"
+    assert_equal "Unknown key: :passing. Valid keys are: :words_connector, :two_words_connector, :last_word_connector, :locale", exception.message
   end
 
   def test_always_returns_string
diff --git a/activesupport/test/core_ext/array/extract_options_test.rb b/activesupport/test/core_ext/array/extract_options_test.rb
index 1651bee0f6..09bf97ae6c 100644
--- a/activesupport/test/core_ext/array/extract_options_test.rb
+++ b/activesupport/test/core_ext/array/extract_options_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 require "active_support/core_ext/hash"
diff --git a/activesupport/test/core_ext/array/grouping_test.rb b/activesupport/test/core_ext/array/grouping_test.rb
index 4c6aadba8c..daf47e9a9f 100644
--- a/activesupport/test/core_ext/array/grouping_test.rb
+++ b/activesupport/test/core_ext/array/grouping_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 
diff --git a/activesupport/test/core_ext/array/prepend_append_test.rb b/activesupport/test/core_ext/array/prepend_append_test.rb
index 763e26191d..3b38acf56c 100644
--- a/activesupport/test/core_ext/array/prepend_append_test.rb
+++ b/activesupport/test/core_ext/array/prepend_append_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 
diff --git a/activesupport/test/core_ext/array/wrap_test.rb b/activesupport/test/core_ext/array/wrap_test.rb
index ae846cb3f2..451f9db2ed 100644
--- a/activesupport/test/core_ext/array/wrap_test.rb
+++ b/activesupport/test/core_ext/array/wrap_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 
diff --git a/activesupport/test/core_ext/bigdecimal_test.rb b/activesupport/test/core_ext/bigdecimal_test.rb
index 43b659546f..dbd0762574 100644
--- a/activesupport/test/core_ext/bigdecimal_test.rb
+++ b/activesupport/test/core_ext/bigdecimal_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/big_decimal"
 
diff --git a/activesupport/test/core_ext/class/attribute_test.rb b/activesupport/test/core_ext/class/attribute_test.rb
index f16043c612..2933b62c58 100644
--- a/activesupport/test/core_ext/class/attribute_test.rb
+++ b/activesupport/test/core_ext/class/attribute_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/class/attribute"
 
diff --git a/activesupport/test/core_ext/class_test.rb b/activesupport/test/core_ext/class_test.rb
index a7905196ae..c0cabea8fd 100644
--- a/activesupport/test/core_ext/class_test.rb
+++ b/activesupport/test/core_ext/class_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/class"
 require "set"
diff --git a/activesupport/test/core_ext/date_and_time_behavior.rb b/activesupport/test/core_ext/date_and_time_behavior.rb
index 6c77e8f313..8d908968ef 100644
--- a/activesupport/test/core_ext/date_and_time_behavior.rb
+++ b/activesupport/test/core_ext/date_and_time_behavior.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 module DateAndTimeBehavior
diff --git a/activesupport/test/core_ext/date_and_time_compatibility_test.rb b/activesupport/test/core_ext/date_and_time_compatibility_test.rb
index 6c6205a4d2..04b93105d5 100644
--- a/activesupport/test/core_ext/date_and_time_compatibility_test.rb
+++ b/activesupport/test/core_ext/date_and_time_compatibility_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "time_zone_test_helpers"
diff --git a/activesupport/test/core_ext/date_ext_test.rb b/activesupport/test/core_ext/date_ext_test.rb
index 50bb1004f7..7c6e705936 100644
--- a/activesupport/test/core_ext/date_ext_test.rb
+++ b/activesupport/test/core_ext/date_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "core_ext/date_and_time_behavior"
diff --git a/activesupport/test/core_ext/date_time_ext_test.rb b/activesupport/test/core_ext/date_time_ext_test.rb
index 276fa2bfd3..beddfe4584 100644
--- a/activesupport/test/core_ext/date_time_ext_test.rb
+++ b/activesupport/test/core_ext/date_time_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "core_ext/date_and_time_behavior"
diff --git a/activesupport/test/core_ext/digest/uuid_test.rb b/activesupport/test/core_ext/digest/uuid_test.rb
index 866a03259a..ea3605bf9c 100644
--- a/activesupport/test/core_ext/digest/uuid_test.rb
+++ b/activesupport/test/core_ext/digest/uuid_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/digest/uuid"
 
diff --git a/activesupport/test/core_ext/duration_test.rb b/activesupport/test/core_ext/duration_test.rb
index 3108f24f21..32c0ce4317 100644
--- a/activesupport/test/core_ext/duration_test.rb
+++ b/activesupport/test/core_ext/duration_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/inflector"
 require "active_support/time"
@@ -315,7 +316,7 @@ class DurationTest < ActiveSupport::TestCase
     assert_equal(1, scalar <=> 5)
     assert_equal(0, scalar <=> 10)
     assert_equal(-1, scalar <=> 15)
-    assert_equal(nil, scalar <=> "foo")
+    assert_nil(scalar <=> "foo")
   end
 
   def test_scalar_plus
diff --git a/activesupport/test/core_ext/enumerable_test.rb b/activesupport/test/core_ext/enumerable_test.rb
index 0b345ecf0f..3259109b0e 100644
--- a/activesupport/test/core_ext/enumerable_test.rb
+++ b/activesupport/test/core_ext/enumerable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/array"
 require "active_support/core_ext/enumerable"
diff --git a/activesupport/test/core_ext/file_test.rb b/activesupport/test/core_ext/file_test.rb
index df5d09acd0..67b1a04429 100644
--- a/activesupport/test/core_ext/file_test.rb
+++ b/activesupport/test/core_ext/file_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/file"
 
diff --git a/activesupport/test/core_ext/hash/transform_keys_test.rb b/activesupport/test/core_ext/hash/transform_keys_test.rb
index 7a11d827f8..f329246bdd 100644
--- a/activesupport/test/core_ext/hash/transform_keys_test.rb
+++ b/activesupport/test/core_ext/hash/transform_keys_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/hash/keys"
 
diff --git a/activesupport/test/core_ext/hash/transform_values_test.rb b/activesupport/test/core_ext/hash/transform_values_test.rb
index f2ac4ce6ce..4eb6999510 100644
--- a/activesupport/test/core_ext/hash/transform_values_test.rb
+++ b/activesupport/test/core_ext/hash/transform_values_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/hash/indifferent_access"
 require "active_support/core_ext/hash/transform_values"
diff --git a/activesupport/test/core_ext/hash_ext_test.rb b/activesupport/test/core_ext/hash_ext_test.rb
index 18da5fcf5f..c533c002a4 100644
--- a/activesupport/test/core_ext/hash_ext_test.rb
+++ b/activesupport/test/core_ext/hash_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/hash"
 require "bigdecimal"
diff --git a/activesupport/test/core_ext/integer_ext_test.rb b/activesupport/test/core_ext/integer_ext_test.rb
index 137e8ce85f..a7ea084e7f 100644
--- a/activesupport/test/core_ext/integer_ext_test.rb
+++ b/activesupport/test/core_ext/integer_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/integer"
 
diff --git a/activesupport/test/core_ext/kernel/concern_test.rb b/activesupport/test/core_ext/kernel/concern_test.rb
index e7e4f99d7e..1f4fb8029c 100644
--- a/activesupport/test/core_ext/kernel/concern_test.rb
+++ b/activesupport/test/core_ext/kernel/concern_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/kernel/concern"
 
diff --git a/activesupport/test/core_ext/kernel_test.rb b/activesupport/test/core_ext/kernel_test.rb
index 26f5088ede..875598f611 100644
--- a/activesupport/test/core_ext/kernel_test.rb
+++ b/activesupport/test/core_ext/kernel_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/kernel"
 
diff --git a/activesupport/test/core_ext/load_error_test.rb b/activesupport/test/core_ext/load_error_test.rb
index 44ff6bb051..3d003fd1d5 100644
--- a/activesupport/test/core_ext/load_error_test.rb
+++ b/activesupport/test/core_ext/load_error_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/load_error"
 
diff --git a/activesupport/test/core_ext/marshal_test.rb b/activesupport/test/core_ext/marshal_test.rb
index cabeed2fae..d17a6fe7f1 100644
--- a/activesupport/test/core_ext/marshal_test.rb
+++ b/activesupport/test/core_ext/marshal_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/marshal"
 require "dependencies_test_helpers"
diff --git a/activesupport/test/core_ext/module/anonymous_test.rb b/activesupport/test/core_ext/module/anonymous_test.rb
index f885444284..d667bc0a34 100644
--- a/activesupport/test/core_ext/module/anonymous_test.rb
+++ b/activesupport/test/core_ext/module/anonymous_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/anonymous"
 
diff --git a/activesupport/test/core_ext/module/attr_internal_test.rb b/activesupport/test/core_ext/module/attr_internal_test.rb
index 8458e278ee..12dc2f101a 100644
--- a/activesupport/test/core_ext/module/attr_internal_test.rb
+++ b/activesupport/test/core_ext/module/attr_internal_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/attr_internal"
 
diff --git a/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb b/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb
index af240bc38d..e8587e3424 100644
--- a/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb
+++ b/activesupport/test/core_ext/module/attribute_accessor_per_thread_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/attribute_accessors_per_thread"
 
diff --git a/activesupport/test/core_ext/module/attribute_accessor_test.rb b/activesupport/test/core_ext/module/attribute_accessor_test.rb
index 464a000d59..2cf33fcc12 100644
--- a/activesupport/test/core_ext/module/attribute_accessor_test.rb
+++ b/activesupport/test/core_ext/module/attribute_accessor_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/attribute_accessors"
 
@@ -12,7 +13,14 @@ class ModuleAttributeAccessorTest < ActiveSupport::TestCase
       cattr_accessor(:defa) { "default_accessor_value" }
       cattr_reader(:defr) { "default_reader_value" }
       cattr_writer(:defw) { "default_writer_value" }
+      cattr_accessor(:deff) { false }
       cattr_accessor(:quux) { :quux }
+
+      cattr_accessor :def_accessor, default: "default_accessor_value"
+      cattr_reader :def_reader, default: "default_reader_value"
+      cattr_writer :def_writer, default: "default_writer_value"
+      cattr_accessor :def_false, default: false
+      cattr_accessor(:def_priority, default: false) { :no_priority }
     end
     @class = Class.new
     @class.instance_eval { include m }
@@ -24,6 +32,21 @@ class ModuleAttributeAccessorTest < ActiveSupport::TestCase
     assert_nil @object.foo
   end
 
+  def test_mattr_default_keyword_arguments
+    assert_equal "default_accessor_value", @module.def_accessor
+    assert_equal "default_reader_value", @module.def_reader
+    assert_equal "default_writer_value", @module.class_variable_get(:@@def_writer)
+  end
+
+  def test_mattr_can_default_to_false
+    assert_equal false, @module.def_false
+    assert_equal false, @module.deff
+  end
+
+  def test_mattr_default_priority
+    assert_equal false, @module.def_priority
+  end
+
   def test_should_set_mattr_value
     @module.foo = :test
     assert_equal :test, @object.foo
@@ -91,9 +114,23 @@ class ModuleAttributeAccessorTest < ActiveSupport::TestCase
     assert_equal "default_writer_value", @module.class_variable_get("@@defw")
   end
 
-  def test_should_not_invoke_default_value_block_multiple_times
+  def test_method_invocation_should_not_invoke_the_default_block
     count = 0
+
     @module.cattr_accessor(:defcount) { count += 1 }
+
     assert_equal 1, count
+    assert_no_difference "count" do
+      @module.defcount
+    end
+  end
+
+  def test_declaring_multiple_attributes_at_once_invokes_the_block_multiple_times
+    count = 0
+
+    @module.cattr_accessor(:defn1, :defn2) { count += 1 }
+
+    assert_equal 1, @module.defn1
+    assert_equal 2, @module.defn2
   end
 end
diff --git a/activesupport/test/core_ext/module/attribute_aliasing_test.rb b/activesupport/test/core_ext/module/attribute_aliasing_test.rb
index fdfa868851..9e5edda77a 100644
--- a/activesupport/test/core_ext/module/attribute_aliasing_test.rb
+++ b/activesupport/test/core_ext/module/attribute_aliasing_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/aliasing"
 
diff --git a/activesupport/test/core_ext/module/concerning_test.rb b/activesupport/test/core_ext/module/concerning_test.rb
index 098036828a..64accc06fc 100644
--- a/activesupport/test/core_ext/module/concerning_test.rb
+++ b/activesupport/test/core_ext/module/concerning_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/concerning"
 
diff --git a/activesupport/test/core_ext/module/introspection_test.rb b/activesupport/test/core_ext/module/introspection_test.rb
index db383850cd..589c9455ed 100644
--- a/activesupport/test/core_ext/module/introspection_test.rb
+++ b/activesupport/test/core_ext/module/introspection_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/introspection"
 
diff --git a/activesupport/test/core_ext/module/reachable_test.rb b/activesupport/test/core_ext/module/reachable_test.rb
index 487c7dee16..f8970bc9f4 100644
--- a/activesupport/test/core_ext/module/reachable_test.rb
+++ b/activesupport/test/core_ext/module/reachable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/reachable"
 
diff --git a/activesupport/test/core_ext/module/remove_method_test.rb b/activesupport/test/core_ext/module/remove_method_test.rb
index 0c627f1e74..327c66e3ec 100644
--- a/activesupport/test/core_ext/module/remove_method_test.rb
+++ b/activesupport/test/core_ext/module/remove_method_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/remove_method"
 
diff --git a/activesupport/test/core_ext/module_test.rb b/activesupport/test/core_ext/module_test.rb
index a4d4444d69..3dd10ab325 100644
--- a/activesupport/test/core_ext/module_test.rb
+++ b/activesupport/test/core_ext/module_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module"
 
@@ -392,4 +393,42 @@ class ModuleTest < ActiveSupport::TestCase
     event = Event.new(Tester.new)
     assert_equal 1, event.foo
   end
+
+  def test_private_delegate
+    location = Class.new do
+      def initialize(place)
+        @place = place
+      end
+
+      private(*delegate(:street, :city, to: :@place))
+    end
+
+    place = location.new(Somewhere.new("Such street", "Sad city"))
+
+    assert_not place.respond_to?(:street)
+    assert_not place.respond_to?(:city)
+
+    assert place.respond_to?(:street, true) # Asking for private method
+    assert place.respond_to?(:city, true)
+  end
+
+  def test_private_delegate_prefixed
+    location = Class.new do
+      def initialize(place)
+        @place = place
+      end
+
+      private(*delegate(:street, :city, to: :@place, prefix: :the))
+    end
+
+    place = location.new(Somewhere.new("Such street", "Sad city"))
+
+    assert_not place.respond_to?(:street)
+    assert_not place.respond_to?(:city)
+
+    assert_not place.respond_to?(:the_street)
+    assert place.respond_to?(:the_street, true)
+    assert_not place.respond_to?(:the_city)
+    assert place.respond_to?(:the_city, true)
+  end
 end
diff --git a/activesupport/test/core_ext/name_error_test.rb b/activesupport/test/core_ext/name_error_test.rb
index fdb9493d3c..a99b20602d 100644
--- a/activesupport/test/core_ext/name_error_test.rb
+++ b/activesupport/test/core_ext/name_error_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/name_error"
 
diff --git a/activesupport/test/core_ext/numeric_ext_test.rb b/activesupport/test/core_ext/numeric_ext_test.rb
index 3cfbe6e7e6..d4e03a90a4 100644
--- a/activesupport/test/core_ext/numeric_ext_test.rb
+++ b/activesupport/test/core_ext/numeric_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "active_support/core_ext/numeric"
diff --git a/activesupport/test/core_ext/object/acts_like_test.rb b/activesupport/test/core_ext/object/acts_like_test.rb
index 631f4e63a8..1f1b71f748 100644
--- a/activesupport/test/core_ext/object/acts_like_test.rb
+++ b/activesupport/test/core_ext/object/acts_like_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object"
 
diff --git a/activesupport/test/core_ext/object/blank_test.rb b/activesupport/test/core_ext/object/blank_test.rb
index 7fd3fed042..fbd96893f6 100644
--- a/activesupport/test/core_ext/object/blank_test.rb
+++ b/activesupport/test/core_ext/object/blank_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object/blank"
 
diff --git a/activesupport/test/core_ext/object/deep_dup_test.rb b/activesupport/test/core_ext/object/deep_dup_test.rb
index f247ee16de..d6f0a71c5b 100644
--- a/activesupport/test/core_ext/object/deep_dup_test.rb
+++ b/activesupport/test/core_ext/object/deep_dup_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object"
 
diff --git a/activesupport/test/core_ext/object/duplicable_test.rb b/activesupport/test/core_ext/object/duplicable_test.rb
index 68b0129980..7607e98b0c 100644
--- a/activesupport/test/core_ext/object/duplicable_test.rb
+++ b/activesupport/test/core_ext/object/duplicable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "bigdecimal"
 require "active_support/core_ext/object/duplicable"
diff --git a/activesupport/test/core_ext/object/inclusion_test.rb b/activesupport/test/core_ext/object/inclusion_test.rb
index 955686d6aa..b706e6b90f 100644
--- a/activesupport/test/core_ext/object/inclusion_test.rb
+++ b/activesupport/test/core_ext/object/inclusion_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object/inclusion"
 
diff --git a/activesupport/test/core_ext/object/instance_variables_test.rb b/activesupport/test/core_ext/object/instance_variables_test.rb
index 5bdb2fbc35..df38282fb0 100644
--- a/activesupport/test/core_ext/object/instance_variables_test.rb
+++ b/activesupport/test/core_ext/object/instance_variables_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object"
 
diff --git a/activesupport/test/core_ext/object/json_cherry_pick_test.rb b/activesupport/test/core_ext/object/json_cherry_pick_test.rb
index dd4e90918e..9f3f92a74b 100644
--- a/activesupport/test/core_ext/object/json_cherry_pick_test.rb
+++ b/activesupport/test/core_ext/object/json_cherry_pick_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 # These test cases were added to test that cherry-picking the json extensions
diff --git a/activesupport/test/core_ext/object/json_gem_encoding_test.rb b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
index f5016d0c2a..3ff34e448e 100644
--- a/activesupport/test/core_ext/object/json_gem_encoding_test.rb
+++ b/activesupport/test/core_ext/object/json_gem_encoding_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "json"
 require "json/encoding_test_cases"
diff --git a/activesupport/test/core_ext/object/to_param_test.rb b/activesupport/test/core_ext/object/to_param_test.rb
index 56246b24f3..e446092abe 100644
--- a/activesupport/test/core_ext/object/to_param_test.rb
+++ b/activesupport/test/core_ext/object/to_param_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object/to_param"
 
diff --git a/activesupport/test/core_ext/object/to_query_test.rb b/activesupport/test/core_ext/object/to_query_test.rb
index 298c8bf373..44147d47cf 100644
--- a/activesupport/test/core_ext/object/to_query_test.rb
+++ b/activesupport/test/core_ext/object/to_query_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/ordered_hash"
 require "active_support/core_ext/object/to_query"
diff --git a/activesupport/test/core_ext/object/try_test.rb b/activesupport/test/core_ext/object/try_test.rb
index 5c8bf59952..fe437f6260 100644
--- a/activesupport/test/core_ext/object/try_test.rb
+++ b/activesupport/test/core_ext/object/try_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object"
 
diff --git a/activesupport/test/core_ext/range_ext_test.rb b/activesupport/test/core_ext/range_ext_test.rb
index d166c7309c..693de2755d 100644
--- a/activesupport/test/core_ext/range_ext_test.rb
+++ b/activesupport/test/core_ext/range_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "active_support/core_ext/numeric"
diff --git a/activesupport/test/core_ext/regexp_ext_test.rb b/activesupport/test/core_ext/regexp_ext_test.rb
index e569a9f234..c937dad1db 100644
--- a/activesupport/test/core_ext/regexp_ext_test.rb
+++ b/activesupport/test/core_ext/regexp_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/regexp"
 
diff --git a/activesupport/test/core_ext/secure_random_test.rb b/activesupport/test/core_ext/secure_random_test.rb
index fc25f6ab41..b2ac4640ab 100644
--- a/activesupport/test/core_ext/secure_random_test.rb
+++ b/activesupport/test/core_ext/secure_random_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/securerandom"
 
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index a98951e889..defec8bba0 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "date"
 require "abstract_unit"
 require "timeout"
@@ -233,7 +234,7 @@ class StringInflectionsTest < ActiveSupport::TestCase
 
   def test_string_squish
     original = %{\u205f\u3000 A string surrounded by various unicode spaces,
-      with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}
+      with tabs(\t\t), newlines(\n\n), unicode nextlines(\u0085\u0085) and many spaces(  ). \u00a0\u2007}.dup
 
     expected = "A string surrounded by various unicode spaces, " \
       "with tabs( ), newlines( ), unicode nextlines( ) and many spaces( )."
@@ -303,8 +304,8 @@ class StringInflectionsTest < ActiveSupport::TestCase
   end
 
   def test_truncate_multibyte
-    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".force_encoding(Encoding::UTF_8),
-      "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".force_encoding(Encoding::UTF_8).truncate(10)
+    assert_equal "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 ...".dup.force_encoding(Encoding::UTF_8),
+      "\354\225\204\353\246\254\353\236\221 \354\225\204\353\246\254 \354\225\204\353\235\274\353\246\254\354\230\244".dup.force_encoding(Encoding::UTF_8).truncate(10)
   end
 
   def test_truncate_should_not_be_html_safe
@@ -325,7 +326,7 @@ class StringInflectionsTest < ActiveSupport::TestCase
   end
 
   def test_remove!
-    original = "This is a very good day to die"
+    original = "This is a very good day to die".dup
     assert_equal "This is a good day to die", original.remove!(" very")
     assert_equal "This is a good day to die", original
     assert_equal "This is a good day", original.remove!(" to ", /die/)
@@ -658,7 +659,7 @@ end
 
 class OutputSafetyTest < ActiveSupport::TestCase
   def setup
-    @string = "hello"
+    @string = "hello".dup
     @object = Class.new(Object) do
       def to_s
         "other"
@@ -734,7 +735,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   end
 
   test "Concatting safe onto unsafe yields unsafe" do
-    @other_string = "other"
+    @other_string = "other".dup
 
     string = @string.html_safe
     @other_string.concat(string)
@@ -757,7 +758,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   end
 
   test "Concatting safe onto unsafe with << yields unsafe" do
-    @other_string = "other"
+    @other_string = "other".dup
     string = @string.html_safe
 
     @other_string << string
@@ -813,7 +814,7 @@ class OutputSafetyTest < ActiveSupport::TestCase
   test "Concatting an integer to safe always yields safe" do
     string = @string.html_safe
     string = string.concat(13)
-    assert_equal "hello".concat(13), string
+    assert_equal "hello".dup.concat(13), string
     assert string.html_safe?
   end
 
@@ -868,7 +869,8 @@ end
 
 class StringIndentTest < ActiveSupport::TestCase
   test "does not indent strings that only contain newlines (edge cases)" do
-    ["", "\n", "\n" * 7].each do |str|
+    ["", "\n", "\n" * 7].each do |string|
+      str = string.dup
       assert_nil str.indent!(8)
       assert_equal str, str.indent(8)
       assert_equal str, str.indent(1, "\t")
diff --git a/activesupport/test/core_ext/time_ext_test.rb b/activesupport/test/core_ext/time_ext_test.rb
index 625a5bffb8..f1c6fa4f8c 100644
--- a/activesupport/test/core_ext/time_ext_test.rb
+++ b/activesupport/test/core_ext/time_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "core_ext/date_and_time_behavior"
diff --git a/activesupport/test/core_ext/time_with_zone_test.rb b/activesupport/test/core_ext/time_with_zone_test.rb
index 70ae793cda..9401b9be07 100644
--- a/activesupport/test/core_ext/time_with_zone_test.rb
+++ b/activesupport/test/core_ext/time_with_zone_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "time_zone_test_helpers"
diff --git a/activesupport/test/core_ext/uri_ext_test.rb b/activesupport/test/core_ext/uri_ext_test.rb
index 0f13ca9c0e..555716d1c3 100644
--- a/activesupport/test/core_ext/uri_ext_test.rb
+++ b/activesupport/test/core_ext/uri_ext_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "uri"
 require "active_support/core_ext/uri"
diff --git a/activesupport/test/current_attributes_test.rb b/activesupport/test/current_attributes_test.rb
index a1f3b33444..a62a4079e3 100644
--- a/activesupport/test/current_attributes_test.rb
+++ b/activesupport/test/current_attributes_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class CurrentAttributesTest < ActiveSupport::TestCase
diff --git a/activesupport/test/dependencies/check_warnings.rb b/activesupport/test/dependencies/check_warnings.rb
index 03c3dca1d6..d177dce295 100644
--- a/activesupport/test/dependencies/check_warnings.rb
+++ b/activesupport/test/dependencies/check_warnings.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 $check_warnings_load_count += 1
 $checked_verbose = $VERBOSE
diff --git a/activesupport/test/dependencies/conflict.rb b/activesupport/test/dependencies/conflict.rb
index 7eff49bbfa..a7199a093b 100644
--- a/activesupport/test/dependencies/conflict.rb
+++ b/activesupport/test/dependencies/conflict.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 Conflict = 1
diff --git a/activesupport/test/dependencies/cross_site_depender.rb b/activesupport/test/dependencies/cross_site_depender.rb
index fbc3b64f56..b414058e27 100644
--- a/activesupport/test/dependencies/cross_site_depender.rb
+++ b/activesupport/test/dependencies/cross_site_depender.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 class CrossSiteDepender
   CrossSiteDependency
 end
diff --git a/activesupport/test/dependencies/mutual_one.rb b/activesupport/test/dependencies/mutual_one.rb
index 05f08f82d3..f739ce2744 100644
--- a/activesupport/test/dependencies/mutual_one.rb
+++ b/activesupport/test/dependencies/mutual_one.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 $mutual_dependencies_count += 1
 require_dependency "mutual_two"
 require_dependency "mutual_two.rb"
diff --git a/activesupport/test/dependencies/mutual_two.rb b/activesupport/test/dependencies/mutual_two.rb
index 1d87d334af..30034be6d1 100644
--- a/activesupport/test/dependencies/mutual_two.rb
+++ b/activesupport/test/dependencies/mutual_two.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 $mutual_dependencies_count += 1
 require_dependency "mutual_one.rb"
 require_dependency "mutual_one"
diff --git a/activesupport/test/dependencies/raises_exception.rb b/activesupport/test/dependencies/raises_exception.rb
index 0a56680fe3..ce9050e572 100644
--- a/activesupport/test/dependencies/raises_exception.rb
+++ b/activesupport/test/dependencies/raises_exception.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 $raises_exception_load_count += 1
 raise Exception, "Loading me failed, so do not add to loaded or history."
 $raises_exception_load_count += 1
diff --git a/activesupport/test/dependencies/raises_exception_without_blame_file.rb b/activesupport/test/dependencies/raises_exception_without_blame_file.rb
index 7c3856b1e6..7fb2a5c8bc 100644
--- a/activesupport/test/dependencies/raises_exception_without_blame_file.rb
+++ b/activesupport/test/dependencies/raises_exception_without_blame_file.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 exception = Exception.new("I am not blamable!")
 class << exception
   undef_method(:blame_file!)
diff --git a/activesupport/test/dependencies/requires_nonexistent0.rb b/activesupport/test/dependencies/requires_nonexistent0.rb
index 7f8a0d8419..86a66203f8 100644
--- a/activesupport/test/dependencies/requires_nonexistent0.rb
+++ b/activesupport/test/dependencies/requires_nonexistent0.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 require "RMagickDontExistDude"
diff --git a/activesupport/test/dependencies/requires_nonexistent1.rb b/activesupport/test/dependencies/requires_nonexistent1.rb
index 0055177d67..a3ec7ce4ef 100644
--- a/activesupport/test/dependencies/requires_nonexistent1.rb
+++ b/activesupport/test/dependencies/requires_nonexistent1.rb
@@ -1 +1,2 @@
+# frozen_string_literal: true
 require_dependency "requires_nonexistent0"
diff --git a/activesupport/test/dependencies/service_one.rb b/activesupport/test/dependencies/service_one.rb
index afc3042269..6149297741 100644
--- a/activesupport/test/dependencies/service_one.rb
+++ b/activesupport/test/dependencies/service_one.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 $loaded_service_one ||= 0
 $loaded_service_one += 1
 
diff --git a/activesupport/test/dependencies/service_two.rb b/activesupport/test/dependencies/service_two.rb
index aabfc3c553..4c013f1fe3 100644
--- a/activesupport/test/dependencies/service_two.rb
+++ b/activesupport/test/dependencies/service_two.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class ServiceTwo
 end
diff --git a/activesupport/test/dependencies_test.rb b/activesupport/test/dependencies_test.rb
index 1ea36418ff..1aad7fc0ec 100644
--- a/activesupport/test/dependencies_test.rb
+++ b/activesupport/test/dependencies_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "pp"
 require "active_support/dependencies"
diff --git a/activesupport/test/dependencies_test_helpers.rb b/activesupport/test/dependencies_test_helpers.rb
index 451195a143..9ba8f3b9b5 100644
--- a/activesupport/test/dependencies_test_helpers.rb
+++ b/activesupport/test/dependencies_test_helpers.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module DependenciesTestHelpers
   def with_loading(*from)
     old_mechanism, ActiveSupport::Dependencies.mechanism = ActiveSupport::Dependencies.mechanism, :load
diff --git a/activesupport/test/deprecation/method_wrappers_test.rb b/activesupport/test/deprecation/method_wrappers_test.rb
index 85d057bb02..33ce4aaeca 100644
--- a/activesupport/test/deprecation/method_wrappers_test.rb
+++ b/activesupport/test/deprecation/method_wrappers_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/deprecation"
 
diff --git a/activesupport/test/deprecation/proxy_wrappers_test.rb b/activesupport/test/deprecation/proxy_wrappers_test.rb
index 67afd75c44..ff38a8165d 100644
--- a/activesupport/test/deprecation/proxy_wrappers_test.rb
+++ b/activesupport/test/deprecation/proxy_wrappers_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/deprecation"
 
diff --git a/activesupport/test/deprecation_test.rb b/activesupport/test/deprecation_test.rb
index 257cb50fb2..22e0ef9afc 100644
--- a/activesupport/test/deprecation_test.rb
+++ b/activesupport/test/deprecation_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/testing/stream"
 
diff --git a/activesupport/test/descendants_tracker_test_cases.rb b/activesupport/test/descendants_tracker_test_cases.rb
index cf349d53ee..abae3f5880 100644
--- a/activesupport/test/descendants_tracker_test_cases.rb
+++ b/activesupport/test/descendants_tracker_test_cases.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "set"
 
 module DescendantsTrackerTestCases
diff --git a/activesupport/test/descendants_tracker_with_autoloading_test.rb b/activesupport/test/descendants_tracker_with_autoloading_test.rb
index e202667a8a..021093956f 100644
--- a/activesupport/test/descendants_tracker_with_autoloading_test.rb
+++ b/activesupport/test/descendants_tracker_with_autoloading_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/descendants_tracker"
 require "active_support/dependencies"
diff --git a/activesupport/test/descendants_tracker_without_autoloading_test.rb b/activesupport/test/descendants_tracker_without_autoloading_test.rb
index 72adc30ace..cadd21be92 100644
--- a/activesupport/test/descendants_tracker_without_autoloading_test.rb
+++ b/activesupport/test/descendants_tracker_without_autoloading_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/descendants_tracker"
 require "descendants_tracker_test_cases"
diff --git a/activesupport/test/evented_file_update_checker_test.rb b/activesupport/test/evented_file_update_checker_test.rb
index f33a5f5764..9450bcb814 100644
--- a/activesupport/test/evented_file_update_checker_test.rb
+++ b/activesupport/test/evented_file_update_checker_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "pathname"
 require "file_update_checker_shared_tests"
diff --git a/activesupport/test/executor_test.rb b/activesupport/test/executor_test.rb
index 7fefc066b3..c522ea9b52 100644
--- a/activesupport/test/executor_test.rb
+++ b/activesupport/test/executor_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class ExecutorTest < ActiveSupport::TestCase
diff --git a/activesupport/test/file_update_checker_shared_tests.rb b/activesupport/test/file_update_checker_shared_tests.rb
index 361e7e2349..90ef886b08 100644
--- a/activesupport/test/file_update_checker_shared_tests.rb
+++ b/activesupport/test/file_update_checker_shared_tests.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "fileutils"
 
 module FileUpdateCheckerSharedTests
diff --git a/activesupport/test/file_update_checker_test.rb b/activesupport/test/file_update_checker_test.rb
index 55b0b46644..5a4e3bebf2 100644
--- a/activesupport/test/file_update_checker_test.rb
+++ b/activesupport/test/file_update_checker_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "file_update_checker_shared_tests"
 
diff --git a/activesupport/test/fixtures/autoload/another_class.rb b/activesupport/test/fixtures/autoload/another_class.rb
index ab6e075ab4..f61698823c 100644
--- a/activesupport/test/fixtures/autoload/another_class.rb
+++ b/activesupport/test/fixtures/autoload/another_class.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class Fixtures::AnotherClass
 end
diff --git a/activesupport/test/fixtures/autoload/some_class.rb b/activesupport/test/fixtures/autoload/some_class.rb
index 30d41eb0bf..a3b5f831ad 100644
--- a/activesupport/test/fixtures/autoload/some_class.rb
+++ b/activesupport/test/fixtures/autoload/some_class.rb
@@ -1,2 +1,3 @@
+# frozen_string_literal: true
 class Fixtures::Autoload::SomeClass
 end
diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
index 33e0cd2a04..592578fedd 100644
--- a/activesupport/test/gzip_test.rb
+++ b/activesupport/test/gzip_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object/blank"
 
diff --git a/activesupport/test/hash_with_indifferent_access_test.rb b/activesupport/test/hash_with_indifferent_access_test.rb
index d68add46cd..b71839a5a2 100644
--- a/activesupport/test/hash_with_indifferent_access_test.rb
+++ b/activesupport/test/hash_with_indifferent_access_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/hash"
 require "bigdecimal"
diff --git a/activesupport/test/i18n_test.rb b/activesupport/test/i18n_test.rb
index 7d88d2dc6b..58ccbdf108 100644
--- a/activesupport/test/i18n_test.rb
+++ b/activesupport/test/i18n_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "active_support/core_ext/array/conversions"
diff --git a/activesupport/test/inflector_test.rb b/activesupport/test/inflector_test.rb
index ef956eda90..b22054ebee 100644
--- a/activesupport/test/inflector_test.rb
+++ b/activesupport/test/inflector_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/inflector"
 
diff --git a/activesupport/test/inflector_test_cases.rb b/activesupport/test/inflector_test_cases.rb
index d61ca3fc18..9b0d2867c2 100644
--- a/activesupport/test/inflector_test_cases.rb
+++ b/activesupport/test/inflector_test_cases.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module InflectorTestCases
   SingularToPlural = {
     "search"      => "searches",
diff --git a/activesupport/test/json/decoding_test.rb b/activesupport/test/json/decoding_test.rb
index 6f5051c312..52687a003f 100644
--- a/activesupport/test/json/decoding_test.rb
+++ b/activesupport/test/json/decoding_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/json"
 require "active_support/time"
diff --git a/activesupport/test/json/encoding_test.rb b/activesupport/test/json/encoding_test.rb
index 6d8f7cfbd0..314c11b2fc 100644
--- a/activesupport/test/json/encoding_test.rb
+++ b/activesupport/test/json/encoding_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "securerandom"
 require "abstract_unit"
 require "active_support/core_ext/string/inflections"
diff --git a/activesupport/test/json/encoding_test_cases.rb b/activesupport/test/json/encoding_test_cases.rb
index 7e4775cec8..2b64aa624d 100644
--- a/activesupport/test/json/encoding_test_cases.rb
+++ b/activesupport/test/json/encoding_test_cases.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "bigdecimal"
 require "date"
 require "time"
diff --git a/activesupport/test/key_generator_test.rb b/activesupport/test/key_generator_test.rb
index 89db9563ac..ae7018274a 100644
--- a/activesupport/test/key_generator_test.rb
+++ b/activesupport/test/key_generator_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 begin
diff --git a/activesupport/test/lazy_load_hooks_test.rb b/activesupport/test/lazy_load_hooks_test.rb
index 3b1959a1c9..761fe46094 100644
--- a/activesupport/test/lazy_load_hooks_test.rb
+++ b/activesupport/test/lazy_load_hooks_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class LazyLoadHooksTest < ActiveSupport::TestCase
diff --git a/activesupport/test/log_subscriber_test.rb b/activesupport/test/log_subscriber_test.rb
index f6496ef7d6..f30932452f 100644
--- a/activesupport/test/log_subscriber_test.rb
+++ b/activesupport/test/log_subscriber_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/log_subscriber/test_helper"
 
diff --git a/activesupport/test/logger_test.rb b/activesupport/test/logger_test.rb
index 3f04783401..cd0ddb4b97 100644
--- a/activesupport/test/logger_test.rb
+++ b/activesupport/test/logger_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "multibyte_test_helpers"
 require "stringio"
@@ -37,7 +38,7 @@ class LoggerTest < ActiveSupport::TestCase
     logger = Logger.new f
     logger.level = Logger::DEBUG
 
-    str = "\x80"
+    str = "\x80".dup
     str.force_encoding("ASCII-8BIT")
 
     logger.add Logger::DEBUG, str
@@ -55,7 +56,7 @@ class LoggerTest < ActiveSupport::TestCase
     logger = Logger.new f
     logger.level = Logger::DEBUG
 
-    str = "\x80"
+    str = "\x80".dup
     str.force_encoding("ASCII-8BIT")
 
     logger.add Logger::DEBUG, str
diff --git a/activesupport/test/message_encryptor_test.rb b/activesupport/test/message_encryptor_test.rb
index 4c3515b5e1..33ab7620da 100644
--- a/activesupport/test/message_encryptor_test.rb
+++ b/activesupport/test/message_encryptor_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "openssl"
 require "active_support/time"
diff --git a/activesupport/test/message_verifier_test.rb b/activesupport/test/message_verifier_test.rb
index d6109c761d..d2964aeb7e 100644
--- a/activesupport/test/message_verifier_test.rb
+++ b/activesupport/test/message_verifier_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "openssl"
 require "active_support/time"
diff --git a/activesupport/test/multibyte_chars_test.rb b/activesupport/test/multibyte_chars_test.rb
index d80d340986..6bef794fe2 100644
--- a/activesupport/test/multibyte_chars_test.rb
+++ b/activesupport/test/multibyte_chars_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "multibyte_test_helpers"
 require "active_support/core_ext/string/multibyte"
@@ -51,7 +52,7 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   end
 
   def test_forwarded_method_with_non_string_result_should_be_returned_verbatim
-    str = ""
+    str = "".dup
     str.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
     @chars.wrapped_string.singleton_class.class_eval { def __method_for_multibyte_testing_with_integer_result; 1; end }
 
@@ -59,14 +60,14 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   end
 
   def test_should_concatenate
-    mb_a = "a".mb_chars
-    mb_b = "b".mb_chars
+    mb_a = "a".dup.mb_chars
+    mb_b = "b".dup.mb_chars
     assert_equal "ab", mb_a + "b"
     assert_equal "ab", "a" + mb_b
     assert_equal "ab", mb_a + mb_b
 
     assert_equal "ab", mb_a << "b"
-    assert_equal "ab", "a" << mb_b
+    assert_equal "ab", "a".dup << mb_b
     assert_equal "abb", mb_a << mb_b
   end
 
@@ -78,7 +79,7 @@ class MultibyteCharsTest < ActiveSupport::TestCase
 
   def test_concatenation_should_return_a_proxy_class_instance
     assert_equal ActiveSupport::Multibyte.proxy_class, ("a".mb_chars + "b").class
-    assert_equal ActiveSupport::Multibyte.proxy_class, ("a".mb_chars << "b").class
+    assert_equal ActiveSupport::Multibyte.proxy_class, ("a".dup.mb_chars << "b").class
   end
 
   def test_ascii_strings_are_treated_at_utf8_strings
@@ -88,8 +89,8 @@ class MultibyteCharsTest < ActiveSupport::TestCase
   def test_concatenate_should_return_proxy_instance
     assert(("a".mb_chars + "b").kind_of?(@proxy_class))
     assert(("a".mb_chars + "b".mb_chars).kind_of?(@proxy_class))
-    assert(("a".mb_chars << "b").kind_of?(@proxy_class))
-    assert(("a".mb_chars << "b".mb_chars).kind_of?(@proxy_class))
+    assert(("a".dup.mb_chars << "b").kind_of?(@proxy_class))
+    assert(("a".dup.mb_chars << "b".mb_chars).kind_of?(@proxy_class))
   end
 
   def test_should_return_string_as_json
@@ -115,12 +116,12 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   %w{capitalize downcase lstrip reverse rstrip swapcase upcase}.each do |method|
     class_eval(<<-EOTESTS, __FILE__, __LINE__ + 1)
       def test_#{method}_bang_should_return_self_when_modifying_wrapped_string
-        chars = ' él piDió Un bUen café '
+        chars = ' él piDió Un bUen café '.dup
         assert_equal chars.object_id, chars.send("#{method}!").object_id
       end
 
       def test_#{method}_bang_should_change_wrapped_string
-        original = ' él piDió Un bUen café '
+        original = ' él piDió Un bUen café '.dup
         proxy = chars(original.dup)
         proxy.send("#{method}!")
         assert_not_equal original, proxy.to_s
@@ -133,7 +134,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_tidy_bytes_bang_should_change_wrapped_string
-    original = " Un bUen café \x92"
+    original = " Un bUen café \x92".dup
     proxy = chars(original.dup)
     proxy.tidy_bytes!
     assert_not_equal original, proxy.to_s
@@ -150,7 +151,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_string_methods_are_chainable
-    assert chars("").insert(0, "").kind_of?(ActiveSupport::Multibyte.proxy_class)
+    assert chars("".dup).insert(0, "").kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").rjust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").ljust(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
     assert chars("").center(1).kind_of?(ActiveSupport::Multibyte.proxy_class)
@@ -195,7 +196,7 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_should_use_character_offsets_for_insert_offsets
-    assert_equal "", "".mb_chars.insert(0, "")
+    assert_equal "", "".dup.mb_chars.insert(0, "")
     assert_equal "こわにちわ", @chars.insert(1, "わ")
     assert_equal "こわわわにちわ", @chars.insert(2, "わわ")
     assert_equal "わこわわわにちわ", @chars.insert(0, "わ")
@@ -418,13 +419,13 @@ class MultibyteCharsUTF8BehaviourTest < ActiveSupport::TestCase
   end
 
   def test_slice_bang_removes_the_slice_from_the_receiver
-    chars = "úüù".mb_chars
+    chars = "úüù".dup.mb_chars
     chars.slice!(0, 2)
     assert_equal "ù", chars
   end
 
   def test_slice_bang_returns_nil_and_does_not_modify_receiver_if_out_of_bounds
-    string = "úüù"
+    string = "úüù".dup
     chars = string.mb_chars
     assert_nil chars.slice!(4, 5)
     assert_equal "úüù", chars
diff --git a/activesupport/test/multibyte_conformance_test.rb b/activesupport/test/multibyte_conformance_test.rb
index ef1a26135f..be89c85c79 100644
--- a/activesupport/test/multibyte_conformance_test.rb
+++ b/activesupport/test/multibyte_conformance_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "multibyte_test_helpers"
 
diff --git a/activesupport/test/multibyte_grapheme_break_conformance_test.rb b/activesupport/test/multibyte_grapheme_break_conformance_test.rb
index b3328987ae..855626e779 100644
--- a/activesupport/test/multibyte_grapheme_break_conformance_test.rb
+++ b/activesupport/test/multibyte_grapheme_break_conformance_test.rb
@@ -1,4 +1,5 @@
 # encoding: utf-8
+# frozen_string_literal: true
 
 require "abstract_unit"
 require "multibyte_test_helpers"
diff --git a/activesupport/test/multibyte_normalization_conformance_test.rb b/activesupport/test/multibyte_normalization_conformance_test.rb
index ebc9f92d23..deb94a7aa3 100644
--- a/activesupport/test/multibyte_normalization_conformance_test.rb
+++ b/activesupport/test/multibyte_normalization_conformance_test.rb
@@ -1,4 +1,5 @@
 # encoding: utf-8
+# frozen_string_literal: true
 
 require "abstract_unit"
 require "multibyte_test_helpers"
diff --git a/activesupport/test/multibyte_proxy_test.rb b/activesupport/test/multibyte_proxy_test.rb
index c303097f80..27d5cea836 100644
--- a/activesupport/test/multibyte_proxy_test.rb
+++ b/activesupport/test/multibyte_proxy_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class MultibyteProxyText < ActiveSupport::TestCase
diff --git a/activesupport/test/multibyte_test_helpers.rb b/activesupport/test/multibyte_test_helpers.rb
index a70516bb08..c3346c233a 100644
--- a/activesupport/test/multibyte_test_helpers.rb
+++ b/activesupport/test/multibyte_test_helpers.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module MultibyteTestHelpers
   class Downloader
     def self.download(from, to)
@@ -23,7 +24,7 @@ module MultibyteTestHelpers
 
   UNICODE_STRING = "こにちわ".freeze
   ASCII_STRING = "ohayo".freeze
-  BYTE_STRING = "\270\236\010\210\245".force_encoding("ASCII-8BIT").freeze
+  BYTE_STRING = "\270\236\010\210\245".dup.force_encoding("ASCII-8BIT").freeze
 
   def chars(str)
     ActiveSupport::Multibyte::Chars.new(str)
diff --git a/activesupport/test/multibyte_unicode_database_test.rb b/activesupport/test/multibyte_unicode_database_test.rb
index 3724782930..0defa6dc54 100644
--- a/activesupport/test/multibyte_unicode_database_test.rb
+++ b/activesupport/test/multibyte_unicode_database_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class MultibyteUnicodeDatabaseTest < ActiveSupport::TestCase
diff --git a/activesupport/test/notifications/evented_notification_test.rb b/activesupport/test/notifications/evented_notification_test.rb
index 24c5befec3..1fd50d540b 100644
--- a/activesupport/test/notifications/evented_notification_test.rb
+++ b/activesupport/test/notifications/evented_notification_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 module ActiveSupport
diff --git a/activesupport/test/notifications/instrumenter_test.rb b/activesupport/test/notifications/instrumenter_test.rb
index 7eacc5cbe7..122afa1cae 100644
--- a/activesupport/test/notifications/instrumenter_test.rb
+++ b/activesupport/test/notifications/instrumenter_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/notifications/instrumenter"
 
diff --git a/activesupport/test/notifications_test.rb b/activesupport/test/notifications_test.rb
index 11f743519f..d92c059f36 100644
--- a/activesupport/test/notifications_test.rb
+++ b/activesupport/test/notifications_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/module/delegation"
 
diff --git a/activesupport/test/number_helper_i18n_test.rb b/activesupport/test/number_helper_i18n_test.rb
index a1d1c41dc2..b5ac343390 100644
--- a/activesupport/test/number_helper_i18n_test.rb
+++ b/activesupport/test/number_helper_i18n_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/number_helper"
 require "active_support/core_ext/hash/keys"
diff --git a/activesupport/test/number_helper_test.rb b/activesupport/test/number_helper_test.rb
index 4caf1428ea..db99ba649f 100644
--- a/activesupport/test/number_helper_test.rb
+++ b/activesupport/test/number_helper_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/number_helper"
 require "active_support/core_ext/string/output_safety"
diff --git a/activesupport/test/option_merger_test.rb b/activesupport/test/option_merger_test.rb
index c5a6d304ee..90291d6ea8 100644
--- a/activesupport/test/option_merger_test.rb
+++ b/activesupport/test/option_merger_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/object/with_options"
 
diff --git a/activesupport/test/ordered_hash_test.rb b/activesupport/test/ordered_hash_test.rb
index 2cefab3832..5d7b83d7a2 100644
--- a/activesupport/test/ordered_hash_test.rb
+++ b/activesupport/test/ordered_hash_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/json"
 require "active_support/core_ext/object/json"
diff --git a/activesupport/test/ordered_options_test.rb b/activesupport/test/ordered_options_test.rb
index 0417911289..7ff8e01540 100644
--- a/activesupport/test/ordered_options_test.rb
+++ b/activesupport/test/ordered_options_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/ordered_options"
 
diff --git a/activesupport/test/reloader_test.rb b/activesupport/test/reloader_test.rb
index bdd80307c7..8dafbff04c 100644
--- a/activesupport/test/reloader_test.rb
+++ b/activesupport/test/reloader_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class ReloaderTest < ActiveSupport::TestCase
diff --git a/activesupport/test/rescuable_test.rb b/activesupport/test/rescuable_test.rb
index 3bdd1651e7..96ed3718af 100644
--- a/activesupport/test/rescuable_test.rb
+++ b/activesupport/test/rescuable_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class WraithAttack < StandardError
diff --git a/activesupport/test/safe_buffer_test.rb b/activesupport/test/safe_buffer_test.rb
index 36c068b91f..5a0f6539a4 100644
--- a/activesupport/test/safe_buffer_test.rb
+++ b/activesupport/test/safe_buffer_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/string/inflections"
 require "yaml"
diff --git a/activesupport/test/security_utils_test.rb b/activesupport/test/security_utils_test.rb
index e8f762da22..34f2eea919 100644
--- a/activesupport/test/security_utils_test.rb
+++ b/activesupport/test/security_utils_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/security_utils"
 
diff --git a/activesupport/test/share_lock_test.rb b/activesupport/test/share_lock_test.rb
index a5970591fa..7d850b4757 100644
--- a/activesupport/test/share_lock_test.rb
+++ b/activesupport/test/share_lock_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "concurrent/atomic/count_down_latch"
 require "active_support/concurrency/share_lock"
diff --git a/activesupport/test/string_inquirer_test.rb b/activesupport/test/string_inquirer_test.rb
index 79a715349c..ba9791886d 100644
--- a/activesupport/test/string_inquirer_test.rb
+++ b/activesupport/test/string_inquirer_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class StringInquirerTest < ActiveSupport::TestCase
diff --git a/activesupport/test/subscriber_test.rb b/activesupport/test/subscriber_test.rb
index 9127da35d4..33f89d237e 100644
--- a/activesupport/test/subscriber_test.rb
+++ b/activesupport/test/subscriber_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/subscriber"
 
diff --git a/activesupport/test/tagged_logging_test.rb b/activesupport/test/tagged_logging_test.rb
index 2469e827d4..e35ddba74b 100644
--- a/activesupport/test/tagged_logging_test.rb
+++ b/activesupport/test/tagged_logging_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/logger"
 require "active_support/tagged_logging"
diff --git a/activesupport/test/test_case_test.rb b/activesupport/test/test_case_test.rb
index 40dfbe2542..bc83fc3f07 100644
--- a/activesupport/test/test_case_test.rb
+++ b/activesupport/test/test_case_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 class AssertDifferenceTest < ActiveSupport::TestCase
diff --git a/activesupport/test/testing/constant_lookup_test.rb b/activesupport/test/testing/constant_lookup_test.rb
index 00e69fcdb5..02ef708a63 100644
--- a/activesupport/test/testing/constant_lookup_test.rb
+++ b/activesupport/test/testing/constant_lookup_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "dependencies_test_helpers"
 
diff --git a/activesupport/test/testing/file_fixtures_test.rb b/activesupport/test/testing/file_fixtures_test.rb
index 9f28252c31..cc00e7f113 100644
--- a/activesupport/test/testing/file_fixtures_test.rb
+++ b/activesupport/test/testing/file_fixtures_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 
 require "pathname"
diff --git a/activesupport/test/testing/method_call_assertions_test.rb b/activesupport/test/testing/method_call_assertions_test.rb
index 7887933b15..3912c19b80 100644
--- a/activesupport/test/testing/method_call_assertions_test.rb
+++ b/activesupport/test/testing/method_call_assertions_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/testing/method_call_assertions"
 
diff --git a/activesupport/test/time_travel_test.rb b/activesupport/test/time_travel_test.rb
index 9d354f14f4..148aa5ef7f 100644
--- a/activesupport/test/time_travel_test.rb
+++ b/activesupport/test/time_travel_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/core_ext/date_time"
 require "active_support/core_ext/numeric/time"
@@ -162,4 +163,26 @@ class TimeTravelTest < ActiveSupport::TestCase
       assert_equal DateTime.now.to_s, DateTimeSubclass.now.to_s
     end
   end
+
+  def test_time_helper_freeze_time
+    expected_time = Time.now
+    freeze_time
+    sleep(1)
+
+    assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+  ensure
+    travel_back
+  end
+
+  def test_time_helper_freeze_time_with_block
+    expected_time = Time.now
+
+    freeze_time do
+      sleep(1)
+
+      assert_equal expected_time.to_s(:db), Time.now.to_s(:db)
+    end
+
+    assert_operator expected_time.to_s(:db), :<, Time.now.to_s(:db)
+  end
 end
diff --git a/activesupport/test/time_zone_test.rb b/activesupport/test/time_zone_test.rb
index de111cc40e..043ff4d385 100644
--- a/activesupport/test/time_zone_test.rb
+++ b/activesupport/test/time_zone_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/time"
 require "time_zone_test_helpers"
@@ -403,6 +404,16 @@ class TimeZoneTest < ActiveSupport::TestCase
     end
   end
 
+  def test_parse_with_invalid_date
+    zone = ActiveSupport::TimeZone["UTC"]
+
+    exception = assert_raises(ArgumentError) do
+      zone.parse("9000")
+    end
+
+    assert_equal "argument out of range", exception.message
+  end
+
   def test_rfc3339
     zone = ActiveSupport::TimeZone["Eastern Time (US & Canada)"]
     twz = zone.rfc3339("1999-12-31T14:00:00-10:00")
diff --git a/activesupport/test/time_zone_test_helpers.rb b/activesupport/test/time_zone_test_helpers.rb
index e1d615d154..118dc38b5c 100644
--- a/activesupport/test/time_zone_test_helpers.rb
+++ b/activesupport/test/time_zone_test_helpers.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 module TimeZoneTestHelpers
   def with_tz_default(tz = nil)
     old_tz = Time.zone
diff --git a/activesupport/test/transliterate_test.rb b/activesupport/test/transliterate_test.rb
index 466b69bcef..1359fe8a8d 100644
--- a/activesupport/test/transliterate_test.rb
+++ b/activesupport/test/transliterate_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/inflector/transliterate"
 
diff --git a/activesupport/test/xml_mini/jdom_engine_test.rb b/activesupport/test/xml_mini/jdom_engine_test.rb
index fc35ac113b..ae78a0e547 100644
--- a/activesupport/test/xml_mini/jdom_engine_test.rb
+++ b/activesupport/test/xml_mini/jdom_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 XMLMiniEngineTest.run_with_platform("java") do
diff --git a/activesupport/test/xml_mini/libxml_engine_test.rb b/activesupport/test/xml_mini/libxml_engine_test.rb
index f3394ad7f2..64ef5b61a1 100644
--- a/activesupport/test/xml_mini/libxml_engine_test.rb
+++ b/activesupport/test/xml_mini/libxml_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 XMLMiniEngineTest.run_with_gem("libxml") do
diff --git a/activesupport/test/xml_mini/libxmlsax_engine_test.rb b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
index f457e160d6..deeb01eefe 100644
--- a/activesupport/test/xml_mini/libxmlsax_engine_test.rb
+++ b/activesupport/test/xml_mini/libxmlsax_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 XMLMiniEngineTest.run_with_gem("libxml") do
diff --git a/activesupport/test/xml_mini/nokogiri_engine_test.rb b/activesupport/test/xml_mini/nokogiri_engine_test.rb
index 3151e75fc0..10062577f6 100644
--- a/activesupport/test/xml_mini/nokogiri_engine_test.rb
+++ b/activesupport/test/xml_mini/nokogiri_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 XMLMiniEngineTest.run_with_gem("nokogiri") do
diff --git a/activesupport/test/xml_mini/nokogirisax_engine_test.rb b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
index 7dafbdaf48..9d298b77d3 100644
--- a/activesupport/test/xml_mini/nokogirisax_engine_test.rb
+++ b/activesupport/test/xml_mini/nokogirisax_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 XMLMiniEngineTest.run_with_gem("nokogiri") do
diff --git a/activesupport/test/xml_mini/rexml_engine_test.rb b/activesupport/test/xml_mini/rexml_engine_test.rb
index c51f0d3c20..29a9dbfbeb 100644
--- a/activesupport/test/xml_mini/rexml_engine_test.rb
+++ b/activesupport/test/xml_mini/rexml_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require_relative "xml_mini_engine_test"
 
 class REXMLEngineTest < XMLMiniEngineTest
diff --git a/activesupport/test/xml_mini/xml_mini_engine_test.rb b/activesupport/test/xml_mini/xml_mini_engine_test.rb
index 244e0b0d3a..6e6be2ff0a 100644
--- a/activesupport/test/xml_mini/xml_mini_engine_test.rb
+++ b/activesupport/test/xml_mini/xml_mini_engine_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/xml_mini"
 require "active_support/core_ext/hash/conversions"
diff --git a/activesupport/test/xml_mini_test.rb b/activesupport/test/xml_mini_test.rb
index b8caa1d74c..cf66e9ff41 100644
--- a/activesupport/test/xml_mini_test.rb
+++ b/activesupport/test/xml_mini_test.rb
@@ -1,3 +1,4 @@
+# frozen_string_literal: true
 require "abstract_unit"
 require "active_support/xml_mini"
 require "active_support/builder"