Merge branch 'master' into active-storage-import

38 files changed, 211 insertions, 110 deletions

diff --git a/Gemfile b/Gemfile
index f2b0ca3a4e..ac9af87ca9 100644
--- a/Gemfile
+++ b/Gemfile
@@ -108,8 +108,7 @@ local_gemfile = File.expand_path(".Gemfile", __dir__)
 instance_eval File.read local_gemfile if File.exist? local_gemfile
 
 group :test do
-  # FIX: Our test suite isn't ready to run in random order yet.
-  gem "minitest", "< 5.3.4"
+  gem "minitest-bisect"
 
   platforms :mri do
     gem "stackprof"
diff --git a/Gemfile.lock b/Gemfile.lock
index b00534675a..76a5af6fbf 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -301,7 +301,12 @@ GEM
     mime-types-data (3.2016.0521)
     mini_magick (4.8.0)
     mini_portile2 (2.2.0)
-    minitest (5.3.3)
+    minitest (5.10.2)
+    minitest-bisect (1.4.0)
+      minitest-server (~> 1.0)
+      path_expander (~> 1.0)
+    minitest-server (1.0.4)
+      minitest (~> 5.0)
     mocha (0.14.0)
       metaclass (~> 0.0.1)
     mono_logger (1.1.0)
@@ -326,6 +331,7 @@ GEM
     parallel (1.11.2)
     parser (2.4.0.0)
       ast (~> 2.2)
+    path_expander (1.0.1)
     pg (0.19.0)
     pg (0.19.0-x64-mingw32)
     pg (0.19.0-x86-mingw32)
@@ -507,6 +513,7 @@ DEPENDENCIES
   listen (>= 3.0.5, < 3.2)
   mini_magick
   minitest (< 5.3.4)
+  minitest-bisect
   mocha (~> 0.14)
   mysql2 (>= 0.4.4)
   nokogiri (>= 1.6.8)
diff --git a/actionmailer/test/base_test.rb b/actionmailer/test/base_test.rb
index 2b0e2165e3..d029329497 100644
--- a/actionmailer/test/base_test.rb
+++ b/actionmailer/test/base_test.rb
@@ -981,8 +981,7 @@ class BasePreviewTest < ActiveSupport::TestCase
   test "has access to params" do
     params = { name: "World" }
 
-    assert_called_with(BaseMailer, :welcome, [params]) do
-      BaseMailerPreview.call(:welcome, params)
-    end
+    message = BaseMailerPreview.call(:welcome, params)
+    assert_equal "World", message["name"].decoded
   end
 end
diff --git a/actionpack/lib/action_dispatch/http/response.rb b/actionpack/lib/action_dispatch/http/response.rb
index 84b2ef253d..b314dbecfe 100644
--- a/actionpack/lib/action_dispatch/http/response.rb
+++ b/actionpack/lib/action_dispatch/http/response.rb
@@ -259,11 +259,10 @@ module ActionDispatch # :nodoc:
     #   response.charset = 'utf-16' # => 'utf-16'
     #   response.charset = nil      # => 'utf-8'
     def charset=(charset)
-      header_info = parsed_content_type_header
+      content_type = parsed_content_type_header.mime_type
       if false == charset
-        set_header CONTENT_TYPE, header_info.mime_type
+        set_content_type content_type, nil
       else
-        content_type = header_info.mime_type
         set_content_type content_type, charset || self.class.default_charset
       end
     end
diff --git a/actionpack/test/journey/gtg/transition_table_test.rb b/actionpack/test/journey/gtg/transition_table_test.rb
index 9fa4c8a10f..9044934f05 100644
--- a/actionpack/test/journey/gtg/transition_table_test.rb
+++ b/actionpack/test/journey/gtg/transition_table_test.rb
@@ -21,7 +21,7 @@ module ActionDispatch
           assert json["accepting"]
         end
 
-        if system("dot -V 2>/dev/null")
+        if system("dot -V", 2 => File::NULL)
           def test_to_svg
             table = tt %w{
               /articles(.:format)
diff --git a/actionview/Rakefile b/actionview/Rakefile
index 0d974cb087..20dfa4e114 100644
--- a/actionview/Rakefile
+++ b/actionview/Rakefile
@@ -37,7 +37,7 @@ namespace :test do
       start_time = Time.now
 
       loop do
-        break if system("lsof -i :4567 >/dev/null")
+        break if system("lsof -i :4567", 1 => File::NULL)
 
         if Time.now - start_time > 5
           puts "Timed out after 5 seconds"
diff --git a/activejob/test/support/integration/adapters/sidekiq.rb b/activejob/test/support/integration/adapters/sidekiq.rb
index b63d16d248..ceb7fb61f2 100644
--- a/activejob/test/support/integration/adapters/sidekiq.rb
+++ b/activejob/test/support/integration/adapters/sidekiq.rb
@@ -38,7 +38,7 @@ module SidekiqJobsManager
       # Sidekiq is not warning-clean :(
       $VERBOSE = false
 
-      $stdin.reopen("/dev/null")
+      $stdin.reopen(File::NULL)
       $stdout.sync = true
       $stderr.sync = true
 
diff --git a/activerecord/lib/active_record/attribute_methods/read.rb b/activerecord/lib/active_record/attribute_methods/read.rb
index 6adaeb0121..615b2fa701 100644
--- a/activerecord/lib/active_record/attribute_methods/read.rb
+++ b/activerecord/lib/active_record/attribute_methods/read.rb
@@ -31,9 +31,11 @@ module ActiveRecord
             temp_method = "__temp__#{safe_name}"
 
             ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+            sync_with_transaction_state = "sync_with_transaction_state" if name == primary_key
 
             generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
               def #{temp_method}
+                #{sync_with_transaction_state}
                 name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
                 _read_attribute(name) { |n| missing_attribute(n, caller) }
               end
@@ -57,6 +59,7 @@ module ActiveRecord
         end
 
         name = self.class.primary_key if name == "id".freeze && self.class.primary_key
+        sync_with_transaction_state if name == self.class.primary_key
         _read_attribute(name, &block)
       end
 
diff --git a/activerecord/lib/active_record/attribute_methods/write.rb b/activerecord/lib/active_record/attribute_methods/write.rb
index fa01f832ac..62c5ce059b 100644
--- a/activerecord/lib/active_record/attribute_methods/write.rb
+++ b/activerecord/lib/active_record/attribute_methods/write.rb
@@ -15,10 +15,12 @@ module ActiveRecord
           def define_method_attribute=(name)
             safe_name = name.unpack("h*".freeze).first
             ActiveRecord::AttributeMethods::AttrNames.set_name_cache safe_name, name
+            sync_with_transaction_state = "sync_with_transaction_state" if name == primary_key
 
             generated_attribute_methods.module_eval <<-STR, __FILE__, __LINE__ + 1
               def __temp__#{safe_name}=(value)
                 name = ::ActiveRecord::AttributeMethods::AttrNames::ATTR_#{safe_name}
+                #{sync_with_transaction_state}
                 _write_attribute(name, value)
               end
               alias_method #{(name + '=').inspect}, :__temp__#{safe_name}=
@@ -38,6 +40,7 @@ module ActiveRecord
         end
 
         name = self.class.primary_key if name == "id".freeze && self.class.primary_key
+        sync_with_transaction_state if name == self.class.primary_key
         _write_attribute(name, value)
       end
 
diff --git a/activerecord/lib/active_record/core.rb b/activerecord/lib/active_record/core.rb
index 8b97dbe5bf..cdd3b5114a 100644
--- a/activerecord/lib/active_record/core.rb
+++ b/activerecord/lib/active_record/core.rb
@@ -168,8 +168,7 @@ module ActiveRecord
 
         id = ids.first
 
-        return super if id.kind_of?(Array) ||
-                         id.is_a?(ActiveRecord::Base)
+        return super if StatementCache.unsupported_value?(id)
 
         key = primary_key
 
@@ -194,7 +193,7 @@ module ActiveRecord
         hash = args.first
 
         return super if !(Hash === hash) || hash.values.any? { |v|
-          v.nil? || Array === v || Hash === v || Relation === v || Base === v
+          StatementCache.unsupported_value?(v)
         }
 
         # We can't cache Post.find_by(author: david) ...yet
diff --git a/activerecord/lib/active_record/relation/merger.rb b/activerecord/lib/active_record/relation/merger.rb
index 182f654897..03824ffff9 100644
--- a/activerecord/lib/active_record/relation/merger.rb
+++ b/activerecord/lib/active_record/relation/merger.rb
@@ -135,19 +135,17 @@ module ActiveRecord
           if other.reordering_value
             # override any order specified in the original relation
             relation.reorder! other.order_values
-          elsif other.order_values
+          elsif other.order_values.any?
             # merge in order_values from relation
             relation.order! other.order_values
           end
 
-          relation.extend(*other.extending_values) unless other.extending_values.blank?
+          extensions = other.extensions - relation.extensions
+          relation.extending!(*extensions) if extensions.any?
         end
 
         def merge_single_values
-          if relation.from_clause.empty?
-            relation.from_clause = other.from_clause
-          end
-          relation.lock_value ||= other.lock_value
+          relation.lock_value ||= other.lock_value if other.lock_value
 
           unless other.create_with_value.blank?
             relation.create_with_value = (relation.create_with_value || {}).merge(other.create_with_value)
@@ -155,11 +153,15 @@ module ActiveRecord
         end
 
         def merge_clauses
-          CLAUSE_METHODS.each do |method|
-            clause = relation.get_value(method)
-            other_clause = other.get_value(method)
-            relation.set_value(method, clause.merge(other_clause))
+          if relation.from_clause.empty? && !other.from_clause.empty?
+            relation.from_clause = other.from_clause
           end
+
+          where_clause = relation.where_clause.merge(other.where_clause)
+          relation.where_clause = where_clause unless where_clause.empty?
+
+          having_clause = relation.having_clause.merge(other.having_clause)
+          relation.having_clause = having_clause unless having_clause.empty?
         end
     end
   end
diff --git a/activerecord/lib/active_record/relation/query_methods.rb b/activerecord/lib/active_record/relation/query_methods.rb
index f7fe968b55..bdc5c27328 100644
--- a/activerecord/lib/active_record/relation/query_methods.rb
+++ b/activerecord/lib/active_record/relation/query_methods.rb
@@ -902,16 +902,17 @@ module ActiveRecord
       @arel ||= build_arel
     end
 
-    # Returns a relation value with a given name
-    def get_value(name) # :nodoc:
-      @values[name] || default_value_for(name)
-    end
+    protected
+      # Returns a relation value with a given name
+      def get_value(name) # :nodoc:
+        @values[name] || default_value_for(name)
+      end
 
-    # Sets the relation value with the given name
-    def set_value(name, value) # :nodoc:
-      assert_mutability!
-      @values[name] = value
-    end
+      # Sets the relation value with the given name
+      def set_value(name, value) # :nodoc:
+        assert_mutability!
+        @values[name] = value
+      end
 
     private
 
diff --git a/activerecord/lib/active_record/statement_cache.rb b/activerecord/lib/active_record/statement_cache.rb
index 64657089b5..2af7d00246 100644
--- a/activerecord/lib/active_record/statement_cache.rb
+++ b/activerecord/lib/active_record/statement_cache.rb
@@ -108,6 +108,11 @@ module ActiveRecord
 
       klass.find_by_sql(sql, bind_values, preparable: true, &block)
     end
-    alias :call :execute
+
+    def self.unsupported_value?(value)
+      case value
+      when NilClass, Array, Range, Hash, Relation, Base then true
+      end
+    end
   end
 end
diff --git a/activerecord/lib/active_record/transactions.rb b/activerecord/lib/active_record/transactions.rb
index 3e8a0789df..f91f0cdf12 100644
--- a/activerecord/lib/active_record/transactions.rb
+++ b/activerecord/lib/active_record/transactions.rb
@@ -432,8 +432,8 @@ module ActiveRecord
             @new_record = restore_state[:new_record]
             @destroyed  = restore_state[:destroyed]
             pk = self.class.primary_key
-            if pk && read_attribute(pk) != restore_state[:id]
-              write_attribute(pk, restore_state[:id])
+            if pk && _read_attribute(pk) != restore_state[:id]
+              _write_attribute(pk, restore_state[:id])
             end
             freeze if restore_state[:frozen?]
           end
diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
index abb7a696ce..6e04578576 100644
--- a/activerecord/test/cases/adapter_test.rb
+++ b/activerecord/test/cases/adapter_test.rb
@@ -158,26 +158,6 @@ module ActiveRecord
       end
     end
 
-    # test resetting sequences in odd tables in PostgreSQL
-    if ActiveRecord::Base.connection.respond_to?(:reset_pk_sequence!)
-      require "models/movie"
-      require "models/subscriber"
-
-      def test_reset_empty_table_with_custom_pk
-        Movie.delete_all
-        Movie.connection.reset_pk_sequence! "movies"
-        assert_equal 1, Movie.create(name: "fight club").id
-      end
-
-      def test_reset_table_with_non_integer_pk
-        Subscriber.delete_all
-        Subscriber.connection.reset_pk_sequence! "subscribers"
-        sub = Subscriber.new(name: "robert drake")
-        sub.id = "bob drake"
-        assert_nothing_raised { sub.save! }
-      end
-    end
-
     def test_uniqueness_violations_are_translated_to_specific_exception
       @connection.execute "INSERT INTO subscribers(nick) VALUES('me')"
       error = assert_raises(ActiveRecord::RecordNotUnique) do
@@ -368,5 +348,25 @@ module ActiveRecord
         assert !@connection.transaction_open?
       end
     end
+
+    # test resetting sequences in odd tables in PostgreSQL
+    if ActiveRecord::Base.connection.respond_to?(:reset_pk_sequence!)
+      require "models/movie"
+      require "models/subscriber"
+
+      def test_reset_empty_table_with_custom_pk
+        Movie.delete_all
+        Movie.connection.reset_pk_sequence! "movies"
+        assert_equal 1, Movie.create(name: "fight club").id
+      end
+
+      def test_reset_table_with_non_integer_pk
+        Subscriber.delete_all
+        Subscriber.connection.reset_pk_sequence! "subscribers"
+        sub = Subscriber.new(name: "robert drake")
+        sub.id = "bob drake"
+        assert_nothing_raised { sub.save! }
+      end
+    end
   end
 end
diff --git a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
index eb602af812..62abd694bb 100644
--- a/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/schema_migrations_test.rb
@@ -3,6 +3,8 @@
 require "cases/helper"
 
 class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
+  self.use_transactional_tests = false
+
   def test_renaming_index_on_foreign_key
     connection.add_index "engines", "car_id"
     connection.add_foreign_key :engines, :cars, name: "fk_engines_cars"
@@ -33,6 +35,8 @@ class SchemaMigrationsTest < ActiveRecord::Mysql2TestCase
 
       assert connection.column_exists?(table_name, :key, :string)
     end
+  ensure
+    ActiveRecord::InternalMetadata[:environment] = ActiveRecord::Migrator.current_environment
   end
 
   private
diff --git a/activerecord/test/cases/adapters/postgresql/hstore_test.rb b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
index 7d8a83a4dd..97a8a257c5 100644
--- a/activerecord/test/cases/adapters/postgresql/hstore_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/hstore_test.rb
@@ -21,12 +21,7 @@ if ActiveRecord::Base.connection.supports_extensions?
     def setup
       @connection = ActiveRecord::Base.connection
 
-      unless @connection.extension_enabled?("hstore")
-        @connection.enable_extension "hstore"
-        @connection.commit_db_transaction
-      end
-
-      @connection.reconnect!
+      enable_extension!("hstore", @connection)
 
       @connection.transaction do
         @connection.create_table("hstores") do |t|
@@ -42,6 +37,7 @@ if ActiveRecord::Base.connection.supports_extensions?
 
     teardown do
       @connection.drop_table "hstores", if_exists: true
+      disable_extension!("hstore", @connection)
     end
 
     def test_hstore_included_in_extensions
diff --git a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
index 5d81a9c258..f199519d86 100644
--- a/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/postgresql_adapter_test.rb
@@ -327,15 +327,18 @@ module ActiveRecord
       end
 
       def test_only_reload_type_map_once_for_every_unrecognized_type
+        reset_connection
+        connection = ActiveRecord::Base.connection
+
         silence_warnings do
           assert_queries 2, ignore_none: true do
-            @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+            connection.select_all "select 'pg_catalog.pg_class'::regclass"
           end
           assert_queries 1, ignore_none: true do
-            @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+            connection.select_all "select 'pg_catalog.pg_class'::regclass"
           end
           assert_queries 2, ignore_none: true do
-            @connection.select_all "SELECT NULL::anyarray"
+            connection.select_all "SELECT NULL::anyarray"
           end
         end
       ensure
@@ -343,10 +346,13 @@ module ActiveRecord
       end
 
       def test_only_warn_on_first_encounter_of_unrecognized_oid
+        reset_connection
+        connection = ActiveRecord::Base.connection
+
         warning = capture(:stderr) {
-          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
-          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
-          @connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          connection.select_all "select 'pg_catalog.pg_class'::regclass"
+          connection.select_all "select 'pg_catalog.pg_class'::regclass"
         }
         assert_match(/\Aunknown OID \d+: failed to recognize type of 'regclass'\. It will be treated as String\.\n\z/, warning)
       ensure
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 2ab8a6bf03..cedb621b4f 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -465,7 +465,10 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_create_resets_cached_counters
+    Reader.delete_all
+
     person = Person.create!(first_name: "tenderlove")
+
     post   = Post.first
 
     assert_equal [], person.readers
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index c2e2bca924..ae492f1c1c 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -1372,7 +1372,7 @@ module AutosaveAssociationOnACollectionAssociationTests
     @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
 
     @pirate.save
-    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+    assert_equal new_names.sort, @pirate.reload.send(@association_name).map(&:name).sort
   end
 
   def test_should_automatically_save_bang_the_associated_models
@@ -1380,7 +1380,7 @@ module AutosaveAssociationOnACollectionAssociationTests
     @pirate.send(@association_name).each_with_index { |child, i| child.name = new_names[i] }
 
     @pirate.save!
-    assert_equal new_names, @pirate.reload.send(@association_name).map(&:name)
+    assert_equal new_names.sort, @pirate.reload.send(@association_name).map(&:name).sort
   end
 
   def test_should_update_children_when_autosave_is_true_and_parent_is_new_but_child_is_not
diff --git a/activerecord/test/cases/calculations_test.rb b/activerecord/test/cases/calculations_test.rb
index 92d071187d..39dff19b78 100644
--- a/activerecord/test/cases/calculations_test.rb
+++ b/activerecord/test/cases/calculations_test.rb
@@ -747,21 +747,27 @@ class CalculationsTest < ActiveRecord::TestCase
   end
 
   def test_pluck_loaded_relation
+    Company.attribute_names # Load schema information so we don't query below
     companies = Company.order(:id).limit(3).load
+
     assert_no_queries do
       assert_equal ["37signals", "Summit", "Microsoft"], companies.pluck(:name)
     end
   end
 
   def test_pluck_loaded_relation_multiple_columns
+    Company.attribute_names # Load schema information so we don't query below
     companies = Company.order(:id).limit(3).load
+
     assert_no_queries do
       assert_equal [[1, "37signals"], [2, "Summit"], [3, "Microsoft"]], companies.pluck(:id, :name)
     end
   end
 
   def test_pluck_loaded_relation_sql_fragment
+    Company.attribute_names # Load schema information so we don't query below
     companies = Company.order(:name).limit(3).load
+
     assert_queries 1 do
       assert_equal ["37signals", "Apex", "Ex Nihilo"], companies.pluck("DISTINCT name")
     end
diff --git a/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
index 7c41050eaa..02e76ce146 100644
--- a/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
+++ b/activerecord/test/cases/connection_adapters/mysql_type_lookup_test.rb
@@ -1,15 +1,22 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "support/connection_helper"
 
 if current_adapter?(:Mysql2Adapter)
   module ActiveRecord
     module ConnectionAdapters
       class MysqlTypeLookupTest < ActiveRecord::TestCase
+        include ConnectionHelper
+
         setup do
           @connection = ActiveRecord::Base.connection
         end
 
+        def teardown
+          reset_connection
+        end
+
         def test_boolean_types
           emulate_booleans(true) do
             assert_lookup_type :boolean, "tinyint(1)"
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index 0b4dce37cc..a0d87dfb90 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -1179,6 +1179,10 @@ class FinderTest < ActiveRecord::TestCase
     assert_equal posts(:eager_other), Post.find_by("id = ?", posts(:eager_other).id)
   end
 
+  test "find_by with range conditions returns the first matching record" do
+    assert_equal posts(:eager_other), Post.find_by(id: posts(:eager_other).id...posts(:misc_by_bob).id)
+  end
+
   test "find_by returns nil if the record is missing" do
     assert_nil Post.find_by("1 = 0")
   end
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index 8197d09621..6b014bcb3d 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -397,6 +397,7 @@ if Account.connection.respond_to?(:reset_pk_sequence!)
   class FixturesResetPkSequenceTest < ActiveRecord::TestCase
     fixtures :accounts
     fixtures :companies
+    self.use_transactional_tests = false
 
     def setup
       @instances = [Account.new(credit_limit: 50), Company.new(name: "RoR Consulting"), Course.new(name: "Test")]
@@ -841,6 +842,8 @@ class FasterFixturesTest < ActiveRecord::TestCase
 end
 
 class FoxyFixturesTest < ActiveRecord::TestCase
+  # Set to false to blow away fixtures cache and ensure our fixtures are loaded
+  self.use_transactional_tests = false
   fixtures :parrots, :parrots_pirates, :pirates, :treasures, :mateys, :ships, :computers,
            :developers, :"admin/accounts", :"admin/users", :live_parrots, :dead_parrots, :books
 
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index 36fc143a31..6ea02ac191 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -143,6 +143,8 @@ def load_schema
   if File.exist?(adapter_specific_schema_file)
     load adapter_specific_schema_file
   end
+
+  ActiveRecord::FixtureSet.reset_cache
 ensure
   $stdout = original_stdout
 end
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 33a4cc0dcb..c887f54560 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -1002,33 +1002,19 @@ class PersistenceTest < ActiveRecord::TestCase
   end
 
   class SaveTest < ActiveRecord::TestCase
-    self.use_transactional_tests = false
-
     def test_save_touch_false
-      widget = Class.new(ActiveRecord::Base) do
-        connection.create_table :widgets, force: true do |t|
-          t.string :name
-          t.timestamps null: false
-        end
-
-        self.table_name = :widgets
-      end
-
-      instance = widget.create!(
+      pet = Pet.create!(
         name: "Bob",
         created_at: 1.day.ago,
         updated_at: 1.day.ago)
 
-      created_at = instance.created_at
-      updated_at = instance.updated_at
+      created_at = pet.created_at
+      updated_at = pet.updated_at
 
-      instance.name = "Barb"
-      instance.save!(touch: false)
-      assert_equal instance.created_at, created_at
-      assert_equal instance.updated_at, updated_at
-    ensure
-      ActiveRecord::Base.connection.drop_table widget.table_name
-      widget.reset_column_information
+      pet.name = "Barb"
+      pet.save!(touch: false)
+      assert_equal pet.created_at, created_at
+      assert_equal pet.updated_at, updated_at
     end
   end
 
diff --git a/activerecord/test/cases/primary_keys_test.rb b/activerecord/test/cases/primary_keys_test.rb
index bda82c095f..df83fe0ea1 100644
--- a/activerecord/test/cases/primary_keys_test.rb
+++ b/activerecord/test/cases/primary_keys_test.rb
@@ -326,7 +326,7 @@ class CompositePrimaryKeyTest < ActiveRecord::TestCase
   def setup
     @connection = ActiveRecord::Base.connection
     @connection.schema_cache.clear!
-    @connection.create_table(:barcodes, primary_key: ["region", "code"], force: true) do |t|
+    @connection.create_table(:uber_barcodes, primary_key: ["region", "code"], force: true) do |t|
       t.string :region
       t.integer :code
     end
@@ -337,11 +337,11 @@ class CompositePrimaryKeyTest < ActiveRecord::TestCase
   end
 
   def teardown
-    @connection.drop_table(:barcodes, if_exists: true)
+    @connection.drop_table(:uber_barcodes, if_exists: true)
   end
 
   def test_composite_primary_key
-    assert_equal ["region", "code"], @connection.primary_keys("barcodes")
+    assert_equal ["region", "code"], @connection.primary_keys("uber_barcodes")
   end
 
   def test_composite_primary_key_out_of_order
@@ -352,7 +352,7 @@ class CompositePrimaryKeyTest < ActiveRecord::TestCase
   def test_primary_key_issues_warning
     model = Class.new(ActiveRecord::Base) do
       def self.table_name
-        "barcodes"
+        "uber_barcodes"
       end
     end
     warning = capture(:stderr) do
@@ -361,9 +361,9 @@ class CompositePrimaryKeyTest < ActiveRecord::TestCase
     assert_match(/WARNING: Active Record does not support composite primary key\./, warning)
   end
 
-  def test_dumping_composite_primary_key
-    schema = dump_table_schema "barcodes"
-    assert_match %r{create_table "barcodes", primary_key: \["region", "code"\]}, schema
+  def test_collectly_dump_composite_primary_key
+    schema = dump_table_schema "uber_barcodes"
+    assert_match %r{create_table "uber_barcodes", primary_key: \["region", "code"\]}, schema
   end
 
   def test_dumping_composite_primary_key_out_of_order
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index f843368a09..d3f4b5bf75 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -133,7 +133,7 @@ class QueryCacheTest < ActiveRecord::TestCase
           assert_cache :off, conn
         end
       ensure
-        ActiveRecord::Base.clear_all_connections!
+        ActiveRecord::Base.connection_pool.disconnect!
       end
     end
   end
diff --git a/activerecord/test/cases/relation_test.rb b/activerecord/test/cases/relation_test.rb
index f22fcd7b5a..c1805aa592 100644
--- a/activerecord/test/cases/relation_test.rb
+++ b/activerecord/test/cases/relation_test.rb
@@ -100,6 +100,14 @@ module ActiveRecord
       assert_equal({ "hello" => "world", "id" => 10 }, relation.scope_for_create)
     end
 
+    def test_empty_scope
+      relation = Relation.new(Post, Post.arel_table, Post.predicate_builder)
+      assert relation.empty_scope?
+
+      relation.merge!(relation)
+      assert relation.empty_scope?
+    end
+
     def test_bad_constants_raise_errors
       assert_raises(NameError) do
         ActiveRecord::Relation::HelloWorld
diff --git a/activerecord/test/cases/reload_models_test.rb b/activerecord/test/cases/reload_models_test.rb
index 67386725cb..72f4bfaf6d 100644
--- a/activerecord/test/cases/reload_models_test.rb
+++ b/activerecord/test/cases/reload_models_test.rb
@@ -5,6 +5,8 @@ require "models/owner"
 require "models/pet"
 
 class ReloadModelsTest < ActiveRecord::TestCase
+  include ActiveSupport::Testing::Isolation
+
   fixtures :pets, :owners
 
   def test_has_one_with_reload
@@ -21,4 +23,4 @@ class ReloadModelsTest < ActiveRecord::TestCase
     pet.owner = Owner.find_by_name("ashley")
     assert_equal pet.owner, Owner.find_by_name("ashley")
   end
-end
+end unless in_memory_db?
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index 6f035b594b..716ca29eda 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -521,6 +521,8 @@ class DefaultScopingWithThreadTest < ActiveRecord::TestCase
   end
 
   def test_default_scope_is_threadsafe
+    2.times { ThreadsafeDeveloper.unscoped.create! }
+
     threads = []
     assert_not_equal 1, ThreadsafeDeveloper.unscoped.count
 
@@ -539,5 +541,7 @@ class DefaultScopingWithThreadTest < ActiveRecord::TestCase
       ThreadsafeDeveloper.connection.close
     end
     threads.each(&:join)
+  ensure
+    ThreadsafeDeveloper.unscoped.destroy_all
   end
 end unless in_memory_db?
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index b771a1d12c..7fd125ab74 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -686,7 +686,7 @@ class TransactionTest < ActiveRecord::TestCase
       raise ActiveRecord::Rollback
     end
 
-    assert_nil movie.id
+    assert_nil movie.movieid
   end
 
   def test_assign_id_after_rollback
@@ -709,8 +709,54 @@ class TransactionTest < ActiveRecord::TestCase
       raise ActiveRecord::Rollback
     end
 
-    movie.id = nil
-    assert_nil movie.id
+    movie.movieid = nil
+    assert_nil movie.movieid
+  end
+
+  def test_read_attribute_after_rollback
+    topic = Topic.new
+
+    Topic.transaction do
+      topic.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_nil topic.read_attribute(:id)
+  end
+
+  def test_read_attribute_with_custom_primary_key_after_rollback
+    movie = Movie.new(name: "foo")
+
+    Movie.transaction do
+      movie.save!
+      raise ActiveRecord::Rollback
+    end
+
+    assert_nil movie.read_attribute(:movieid)
+  end
+
+  def test_write_attribute_after_rollback
+    topic = Topic.create!
+
+    Topic.transaction do
+      topic.save!
+      raise ActiveRecord::Rollback
+    end
+
+    topic.write_attribute(:id, nil)
+    assert_nil topic.id
+  end
+
+  def test_write_attribute_with_custom_primary_key_after_rollback
+    movie = Movie.create!(name: "foo")
+
+    Movie.transaction do
+      movie.save!
+      raise ActiveRecord::Rollback
+    end
+
+    movie.write_attribute(:movieid, nil)
+    assert_nil movie.movieid
   end
 
   def test_rollback_of_frozen_records
diff --git a/activesupport/test/cache/stores/mem_cache_store_test.rb b/activesupport/test/cache/stores/mem_cache_store_test.rb
index becc1f7fbf..1b73fb65eb 100644
--- a/activesupport/test/cache/stores/mem_cache_store_test.rb
+++ b/activesupport/test/cache/stores/mem_cache_store_test.rb
@@ -24,7 +24,7 @@ class MemCacheStoreTest < ActiveSupport::TestCase
     @data = @cache.instance_variable_get(:@data)
     @cache.clear
     @cache.silence!
-    @cache.logger = ActiveSupport::Logger.new("/dev/null")
+    @cache.logger = ActiveSupport::Logger.new(File::NULL)
   end
 
   include CacheStoreBehavior
diff --git a/activesupport/test/current_attributes_test.rb b/activesupport/test/current_attributes_test.rb
index d333ffc8f5..1669f08f68 100644
--- a/activesupport/test/current_attributes_test.rb
+++ b/activesupport/test/current_attributes_test.rb
@@ -30,7 +30,14 @@ class CurrentAttributesTest < ActiveSupport::TestCase
     end
   end
 
-  setup { Current.reset }
+  setup do
+    @original_time_zone = Time.zone
+    Current.reset
+  end
+
+  teardown do
+    Time.zone = @original_time_zone
+  end
 
   test "read and write attribute" do
     Current.world = "world/1"
diff --git a/ci/travis.rb b/ci/travis.rb
index 6e002d4a5b..8339e0d08b 100755
--- a/ci/travis.rb
+++ b/ci/travis.rb
@@ -14,7 +14,7 @@ commands = [
 ]
 
 commands.each do |command|
-  system("#{command} > /dev/null 2>&1")
+  system(command, [1, 2] => File::NULL)
 end
 
 class Build
diff --git a/railties/test/application/test_runner_test.rb b/railties/test/application/test_runner_test.rb
index bcd311c461..be50fdb49b 100644
--- a/railties/test/application/test_runner_test.rb
+++ b/railties/test/application/test_runner_test.rb
@@ -515,7 +515,7 @@ module ApplicationTests
       create_test_file :models, "post", pass: false
 
       output = run_test_command("test/models/post_test.rb")
-      assert_match %r{Finished in.*\n\n1 runs, 1 assertions}, output
+      assert_match %r{Finished in.*\n1 runs, 1 assertions}, output
     end
 
     def test_fail_fast
diff --git a/railties/test/application/test_test.rb b/railties/test/application/test_test.rb
index 32d2a6857c..2a1a6bcbfd 100644
--- a/railties/test/application/test_test.rb
+++ b/railties/test/application/test_test.rb
@@ -55,7 +55,7 @@ module ApplicationTests
         end
       RUBY
 
-      assert_unsuccessful_run "unit/foo_test.rb", "Failed assertion"
+      assert_unsuccessful_run "unit/foo_test.rb", "Failure:\nFooTest#test_truth"
     end
 
     test "integration test" do
diff --git a/railties/test/generators/plugin_test_runner_test.rb b/railties/test/generators/plugin_test_runner_test.rb
index 0bdd2a77d2..f9c860b04a 100644
--- a/railties/test/generators/plugin_test_runner_test.rb
+++ b/railties/test/generators/plugin_test_runner_test.rb
@@ -71,7 +71,7 @@ class PluginTestRunnerTest < ActiveSupport::TestCase
     create_test_file "post", pass: false
 
     output = run_test_command("test/post_test.rb")
-    assert_match %r{Finished in.*\n\n1 runs, 1 assertions}, output
+    assert_match %r{Finished in.*\n1 runs, 1 assertions}, output
   end
 
   def test_fail_fast