Merge branch 'master' into feature/reselect-method

95 files changed, 1609 insertions, 614 deletions

diff --git a/activerecord/test/cases/adapter_test.rb b/activerecord/test/cases/adapter_test.rb
index 59b99351d1..64c2b51f83 100644
--- a/activerecord/test/cases/adapter_test.rb
+++ b/activerecord/test/cases/adapter_test.rb
@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require "cases/helper"
+require "support/connection_helper"
 require "models/book"
 require "models/post"
 require "models/author"
@@ -10,6 +11,7 @@ module ActiveRecord
   class AdapterTest < ActiveRecord::TestCase
     def setup
       @connection = ActiveRecord::Base.connection
+      @connection.materialize_transactions
     end
 
     ##
@@ -225,7 +227,7 @@ module ActiveRecord
         post = Post.create!(title: "foo", body: "bar")
         expected = @connection.select_all("SELECT * FROM posts WHERE id = #{post.id}")
         result = @connection.select_all("SELECT * FROM posts WHERE id = #{Arel::Nodes::BindParam.new(nil).to_sql}", nil, [[nil, post.id]])
-        assert_equal expected.to_hash, result.to_hash
+        assert_equal expected.to_a, result.to_a
       end
 
       def test_insert_update_delete_with_legacy_binds
@@ -288,7 +290,7 @@ module ActiveRecord
       def test_log_invalid_encoding
         error = assert_raises RuntimeError do
           @connection.send :log, "SELECT 'ы' FROM DUAL" do
-            raise "ы".dup.force_encoding(Encoding::ASCII_8BIT)
+            raise (+"ы").force_encoding(Encoding::ASCII_8BIT)
           end
         end
 
@@ -299,6 +301,34 @@ module ActiveRecord
     def test_supports_multi_insert_is_deprecated
       assert_deprecated { @connection.supports_multi_insert? }
     end
+
+    def test_column_name_length_is_deprecated
+      assert_deprecated { @connection.column_name_length }
+    end
+
+    def test_table_name_length_is_deprecated
+      assert_deprecated { @connection.table_name_length }
+    end
+
+    def test_columns_per_table_is_deprecated
+      assert_deprecated { @connection.columns_per_table }
+    end
+
+    def test_indexes_per_table_is_deprecated
+      assert_deprecated { @connection.indexes_per_table }
+    end
+
+    def test_columns_per_multicolumn_index_is_deprecated
+      assert_deprecated { @connection.columns_per_multicolumn_index }
+    end
+
+    def test_sql_query_length_is_deprecated
+      assert_deprecated { @connection.sql_query_length }
+    end
+
+    def test_joins_per_query_is_deprecated
+      assert_deprecated { @connection.joins_per_query }
+    end
   end
 
   class AdapterForeignKeyTest < ActiveRecord::TestCase
@@ -417,3 +447,27 @@ module ActiveRecord
     end
   end
 end
+
+if ActiveRecord::Base.connection.supports_advisory_locks?
+  class AdvisoryLocksEnabledTest < ActiveRecord::TestCase
+    include ConnectionHelper
+
+    def test_advisory_locks_enabled?
+      assert ActiveRecord::Base.connection.advisory_locks_enabled?
+
+      run_without_connection do |orig_connection|
+        ActiveRecord::Base.establish_connection(
+          orig_connection.merge(advisory_locks: false)
+        )
+
+        assert_not ActiveRecord::Base.connection.advisory_locks_enabled?
+
+        ActiveRecord::Base.establish_connection(
+          orig_connection.merge(advisory_locks: true)
+        )
+
+        assert ActiveRecord::Base.connection.advisory_locks_enabled?
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
index 6fc9df5083..261fee13eb 100644
--- a/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/active_schema_test.rb
@@ -106,7 +106,7 @@ class Mysql2ActiveSchemaTest < ActiveRecord::Mysql2TestCase
   end
 
   def test_create_mysql_database_with_encoding
-    assert_equal "CREATE DATABASE `matt` DEFAULT CHARACTER SET `utf8`", create_database(:matt)
+    assert_equal "CREATE DATABASE `matt` DEFAULT CHARACTER SET `utf8mb4`", create_database(:matt)
     assert_equal "CREATE DATABASE `aimonetti` DEFAULT CHARACTER SET `latin1`", create_database(:aimonetti, charset: "latin1")
     assert_equal "CREATE DATABASE `matt_aimonetti` DEFAULT COLLATE `utf8mb4_bin`", create_database(:matt_aimonetti, collation: "utf8mb4_bin")
   end
diff --git a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
index aa870349be..c32475c683 100644
--- a/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/case_sensitivity_test.rb
@@ -9,8 +9,8 @@ class Mysql2CaseSensitivityTest < ActiveRecord::Mysql2TestCase
   repair_validations(CollationTest)
 
   def test_columns_include_collation_different_from_table
-    assert_equal "utf8_bin", CollationTest.columns_hash["string_cs_column"].collation
-    assert_equal "utf8_general_ci", CollationTest.columns_hash["string_ci_column"].collation
+    assert_equal "utf8mb4_bin", CollationTest.columns_hash["string_cs_column"].collation
+    assert_equal "utf8mb4_general_ci", CollationTest.columns_hash["string_ci_column"].collation
   end
 
   def test_case_sensitive
diff --git a/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
index d0c57de65d..0bdbefdfb9 100644
--- a/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/charset_collation_test.rb
@@ -32,20 +32,20 @@ class Mysql2CharsetCollationTest < ActiveRecord::Mysql2TestCase
   end
 
   test "add column with charset and collation" do
-    @connection.add_column :charset_collations, :title, :string, charset: "utf8", collation: "utf8_bin"
+    @connection.add_column :charset_collations, :title, :string, charset: "utf8mb4", collation: "utf8mb4_bin"
 
     column = @connection.columns(:charset_collations).find { |c| c.name == "title" }
     assert_equal :string, column.type
-    assert_equal "utf8_bin", column.collation
+    assert_equal "utf8mb4_bin", column.collation
   end
 
   test "change column with charset and collation" do
-    @connection.add_column :charset_collations, :description, :string, charset: "utf8", collation: "utf8_unicode_ci"
-    @connection.change_column :charset_collations, :description, :text, charset: "utf8", collation: "utf8_general_ci"
+    @connection.add_column :charset_collations, :description, :string, charset: "utf8mb4", collation: "utf8mb4_unicode_ci"
+    @connection.change_column :charset_collations, :description, :text, charset: "utf8mb4", collation: "utf8mb4_general_ci"
 
     column = @connection.columns(:charset_collations).find { |c| c.name == "description" }
     assert_equal :text, column.type
-    assert_equal "utf8_general_ci", column.collation
+    assert_equal "utf8mb4_general_ci", column.collation
   end
 
   test "schema dump includes collation" do
diff --git a/activerecord/test/cases/adapters/mysql2/connection_test.rb b/activerecord/test/cases/adapters/mysql2/connection_test.rb
index 726f58d58e..3103589186 100644
--- a/activerecord/test/cases/adapters/mysql2/connection_test.rb
+++ b/activerecord/test/cases/adapters/mysql2/connection_test.rb
@@ -104,8 +104,8 @@ class Mysql2ConnectionTest < ActiveRecord::Mysql2TestCase
   end
 
   def test_mysql_connection_collation_is_configured
-    assert_equal "utf8_unicode_ci", @connection.show_variable("collation_connection")
-    assert_equal "utf8_general_ci", ARUnit2Model.connection.show_variable("collation_connection")
+    assert_equal "utf8mb4_unicode_ci", @connection.show_variable("collation_connection")
+    assert_equal "utf8mb4_general_ci", ARUnit2Model.connection.show_variable("collation_connection")
   end
 
   def test_mysql_default_in_strict_mode
@@ -170,6 +170,8 @@ class Mysql2ConnectionTest < ActiveRecord::Mysql2TestCase
   end
 
   def test_logs_name_show_variable
+    ActiveRecord::Base.connection.materialize_transactions
+    @subscriber.logged.clear
     @connection.show_variable "foo"
     assert_equal "SCHEMA", @subscriber.logged[0][1]
   end
diff --git a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
index 308ad1d854..afd422881b 100644
--- a/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/active_schema_test.rb
@@ -4,6 +4,8 @@ require "cases/helper"
 
 class PostgresqlActiveSchemaTest < ActiveRecord::PostgreSQLTestCase
   def setup
+    ActiveRecord::Base.connection.materialize_transactions
+
     ActiveRecord::ConnectionAdapters::PostgreSQLAdapter.class_eval do
       def execute(sql, name = nil) sql end
     end
diff --git a/activerecord/test/cases/adapters/postgresql/bytea_test.rb b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
index 64bb6906cd..3988c2adca 100644
--- a/activerecord/test/cases/adapters/postgresql/bytea_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/bytea_test.rb
@@ -49,7 +49,7 @@ class PostgresqlByteaTest < ActiveRecord::PostgreSQLTestCase
   end
 
   def test_type_cast_binary_value
-    data = "\u001F\x8B".dup.force_encoding("BINARY")
+    data = (+"\u001F\x8B").force_encoding("BINARY")
     assert_equal(data, @type.deserialize(data))
   end
 
diff --git a/activerecord/test/cases/adapters/postgresql/connection_test.rb b/activerecord/test/cases/adapters/postgresql/connection_test.rb
index 54b0dde7dc..70aa189893 100644
--- a/activerecord/test/cases/adapters/postgresql/connection_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/connection_test.rb
@@ -15,8 +15,9 @@ module ActiveRecord
     def setup
       super
       @subscriber = SQLSubscriber.new
-      @subscription = ActiveSupport::Notifications.subscribe("sql.active_record", @subscriber)
       @connection = ActiveRecord::Base.connection
+      @connection.materialize_transactions
+      @subscription = ActiveSupport::Notifications.subscribe("sql.active_record", @subscriber)
     end
 
     def teardown
diff --git a/activerecord/test/cases/adapters/postgresql/money_test.rb b/activerecord/test/cases/adapters/postgresql/money_test.rb
index 61e75e772d..75e5aaed53 100644
--- a/activerecord/test/cases/adapters/postgresql/money_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/money_test.rb
@@ -52,10 +52,10 @@ class PostgresqlMoneyTest < ActiveRecord::PostgreSQLTestCase
 
   def test_money_type_cast
     type = PostgresqlMoney.type_for_attribute("wealth")
-    assert_equal(12345678.12, type.cast("$12,345,678.12".dup))
-    assert_equal(12345678.12, type.cast("$12.345.678,12".dup))
-    assert_equal(-1.15, type.cast("-$1.15".dup))
-    assert_equal(-2.25, type.cast("($2.25)".dup))
+    assert_equal(12345678.12, type.cast(+"$12,345,678.12"))
+    assert_equal(12345678.12, type.cast(+"$12.345.678,12"))
+    assert_equal(-1.15, type.cast(+"-$1.15"))
+    assert_equal(-2.25, type.cast(+"($2.25)"))
   end
 
   def test_schema_dumping
@@ -65,7 +65,7 @@ class PostgresqlMoneyTest < ActiveRecord::PostgreSQLTestCase
   end
 
   def test_create_and_update_money
-    money = PostgresqlMoney.create(wealth: "987.65".dup)
+    money = PostgresqlMoney.create(wealth: +"987.65")
     assert_equal 987.65, money.wealth
 
     new_value = BigDecimal("123.45")
diff --git a/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
index 0bcc214c24..ba477c63f4 100644
--- a/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
+++ b/activerecord/test/cases/adapters/postgresql/referential_integrity_test.rb
@@ -101,7 +101,7 @@ class PostgreSQLReferentialIntegrityTest < ActiveRecord::PostgreSQLTestCase
     @connection.extend ProgrammerMistake
 
     assert_raises ArgumentError do
-      @connection.disable_referential_integrity {}
+      @connection.disable_referential_integrity { }
     end
   end
 
diff --git a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
index d1d4d545a3..89052019f8 100644
--- a/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
+++ b/activerecord/test/cases/adapters/sqlite3/sqlite3_adapter_test.rb
@@ -87,7 +87,7 @@ module ActiveRecord
 
       def test_connection_no_db
         assert_raises(ArgumentError) do
-          Base.sqlite3_connection {}
+          Base.sqlite3_connection { }
         end
       end
 
@@ -167,7 +167,7 @@ module ActiveRecord
             data binary
           )
         eosql
-        str = "\x80".dup.force_encoding("ASCII-8BIT")
+        str = (+"\x80").force_encoding("ASCII-8BIT")
         binary = DualEncoding.new name: "いただきます！", data: str
         binary.save!
         assert_equal str, binary.data
@@ -176,7 +176,7 @@ module ActiveRecord
       end
 
       def test_type_cast_should_not_mutate_encoding
-        name = "hello".dup.force_encoding(Encoding::ASCII_8BIT)
+        name = (+"hello").force_encoding(Encoding::ASCII_8BIT)
         Owner.create(name: name)
         assert_equal Encoding::ASCII_8BIT, name.encoding
       ensure
@@ -345,6 +345,42 @@ module ActiveRecord
         end
       end
 
+      if ActiveRecord::Base.connection.supports_expression_index?
+        def test_expression_index
+          with_example_table do
+            @conn.add_index "ex", "max(id, number)", name: "expression"
+            index = @conn.indexes("ex").find { |idx| idx.name == "expression" }
+            assert_equal "max(id, number)", index.columns
+          end
+        end
+
+        def test_expression_index_with_where
+          with_example_table do
+            @conn.add_index "ex", "id % 10, max(id, number)", name: "expression", where: "id > 1000"
+            index = @conn.indexes("ex").find { |idx| idx.name == "expression" }
+            assert_equal "id % 10, max(id, number)", index.columns
+            assert_equal "id > 1000", index.where
+          end
+        end
+
+        def test_complicated_expression
+          with_example_table do
+            @conn.execute "CREATE INDEX expression ON ex (id % 10, (CASE WHEN number > 0 THEN max(id, number) END))WHERE(id > 1000)"
+            index = @conn.indexes("ex").find { |idx| idx.name == "expression" }
+            assert_equal "id % 10, (CASE WHEN number > 0 THEN max(id, number) END)", index.columns
+            assert_equal "(id > 1000)", index.where
+          end
+        end
+
+        def test_not_everything_an_expression
+          with_example_table do
+            @conn.add_index "ex", "id, max(id, number)", name: "expression"
+            index = @conn.indexes("ex").find { |idx| idx.name == "expression" }
+            assert_equal "id, max(id, number)", index.columns
+          end
+        end
+      end
+
       def test_primary_key
         with_example_table do
           assert_equal "id", @conn.primary_key("ex")
diff --git a/activerecord/test/cases/arel/collectors/sql_string_test.rb b/activerecord/test/cases/arel/collectors/sql_string_test.rb
index 380573494d..443c7eb54b 100644
--- a/activerecord/test/cases/arel/collectors/sql_string_test.rb
+++ b/activerecord/test/cases/arel/collectors/sql_string_test.rb
@@ -19,27 +19,21 @@ module Arel
         collect(node).value
       end
 
-      def ast_with_binds(bv)
+      def ast_with_binds
         table = Table.new(:users)
         manager = Arel::SelectManager.new table
-        manager.where(table[:age].eq(bv))
-        manager.where(table[:name].eq(bv))
+        manager.where(table[:age].eq(Nodes::BindParam.new("hello")))
+        manager.where(table[:name].eq(Nodes::BindParam.new("world")))
         manager.ast
       end
 
       def test_compile
-        bv = Nodes::BindParam.new(1)
-        collector = collect ast_with_binds bv
-
-        sql = collector.compile ["hello", "world"]
+        sql = compile(ast_with_binds)
         assert_equal 'SELECT FROM "users" WHERE "users"."age" = ? AND "users"."name" = ?', sql
       end
 
       def test_returned_sql_uses_utf8_encoding
-        bv = Nodes::BindParam.new(1)
-        collector = collect ast_with_binds bv
-
-        sql = collector.compile ["hello", "world"]
+        sql = compile(ast_with_binds)
         assert_equal sql.encoding, Encoding::UTF_8
       end
     end
diff --git a/activerecord/test/cases/arel/delete_manager_test.rb b/activerecord/test/cases/arel/delete_manager_test.rb
index 17a5271039..0bad02f4d2 100644
--- a/activerecord/test/cases/arel/delete_manager_test.rb
+++ b/activerecord/test/cases/arel/delete_manager_test.rb
@@ -15,6 +15,7 @@ module Arel
       dm = Arel::DeleteManager.new
       dm.take 10
       dm.from table
+      dm.key = table[:id]
       assert_match(/LIMIT 10/, dm.to_sql)
     end
 
diff --git a/activerecord/test/cases/arel/select_manager_test.rb b/activerecord/test/cases/arel/select_manager_test.rb
index c17487ae88..5220950905 100644
--- a/activerecord/test/cases/arel/select_manager_test.rb
+++ b/activerecord/test/cases/arel/select_manager_test.rb
@@ -131,7 +131,7 @@ module Arel
           right = table.alias
           mgr   = table.from
           mgr.join(right).on("omg")
-          mgr.to_sql.must_be_like %{ SELECT  FROM "users" INNER JOIN "users" "users_2" ON omg }
+          mgr.to_sql.must_be_like %{ SELECT FROM "users" INNER JOIN "users" "users_2" ON omg }
         end
 
         it "converts to sqlliterals with multiple items" do
@@ -139,7 +139,7 @@ module Arel
           right = table.alias
           mgr   = table.from
           mgr.join(right).on("omg", "123")
-          mgr.to_sql.must_be_like %{ SELECT  FROM "users" INNER JOIN "users" "users_2" ON omg AND 123 }
+          mgr.to_sql.must_be_like %{ SELECT FROM "users" INNER JOIN "users" "users_2" ON omg AND 123 }
         end
       end
     end
diff --git a/activerecord/test/cases/arel/visitors/depth_first_test.rb b/activerecord/test/cases/arel/visitors/depth_first_test.rb
index 3baccc7316..f94ad521d7 100644
--- a/activerecord/test/cases/arel/visitors/depth_first_test.rb
+++ b/activerecord/test/cases/arel/visitors/depth_first_test.rb
@@ -33,7 +33,6 @@ module Arel
         Arel::Nodes::Ordering,
         Arel::Nodes::StringJoin,
         Arel::Nodes::UnqualifiedColumn,
-        Arel::Nodes::Top,
         Arel::Nodes::Limit,
         Arel::Nodes::Else,
       ].each do |klass|
diff --git a/activerecord/test/cases/arel/visitors/dot_test.rb b/activerecord/test/cases/arel/visitors/dot_test.rb
index 98f3bab620..6b3c132f83 100644
--- a/activerecord/test/cases/arel/visitors/dot_test.rb
+++ b/activerecord/test/cases/arel/visitors/dot_test.rb
@@ -37,7 +37,6 @@ module Arel
         Arel::Nodes::Offset,
         Arel::Nodes::Ordering,
         Arel::Nodes::UnqualifiedColumn,
-        Arel::Nodes::Top,
         Arel::Nodes::Limit,
       ].each do |klass|
         define_method("test_#{klass.name.gsub('::', '_')}") do
diff --git a/activerecord/test/cases/arel/visitors/to_sql_test.rb b/activerecord/test/cases/arel/visitors/to_sql_test.rb
index e8ac50bfa3..b6426a211e 100644
--- a/activerecord/test/cases/arel/visitors/to_sql_test.rb
+++ b/activerecord/test/cases/arel/visitors/to_sql_test.rb
@@ -221,7 +221,7 @@ module Arel
         sql.must_be_like "foo AS bar"
       end
 
-      it "should visit_Bignum" do
+      it "should visit_Integer" do
         compile 8787878092
       end
 
diff --git a/activerecord/test/cases/associations/belongs_to_associations_test.rb b/activerecord/test/cases/associations/belongs_to_associations_test.rb
index 0cc4ed7127..1fca1be181 100644
--- a/activerecord/test/cases/associations/belongs_to_associations_test.rb
+++ b/activerecord/test/cases/associations/belongs_to_associations_test.rb
@@ -452,15 +452,39 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_belongs_to_counter_with_assigning_nil
-    post = Post.find(1)
-    comment = Comment.find(1)
+    topic = Topic.create!(title: "debate")
+    reply = Reply.create!(title: "blah!", content: "world around!", topic: topic)
 
-    assert_equal post.id, comment.post_id
-    assert_equal 2, Post.find(post.id).comments.size
+    assert_equal topic.id, reply.parent_id
+    assert_equal 1, topic.reload.replies.size
 
-    comment.post = nil
+    reply.topic = nil
+    reply.reload
 
-    assert_equal 1, Post.find(post.id).comments.size
+    assert_equal topic.id, reply.parent_id
+    assert_equal 1, topic.reload.replies.size
+
+    reply.topic = nil
+    reply.save!
+
+    assert_equal 0, topic.reload.replies.size
+  end
+
+  def test_belongs_to_counter_with_assigning_new_object
+    topic = Topic.create!(title: "debate")
+    reply = Reply.create!(title: "blah!", content: "world around!", topic: topic)
+
+    assert_equal topic.id, reply.parent_id
+    assert_equal 1, topic.reload.replies_count
+
+    topic2 = reply.build_topic(title: "debate2")
+    reply.save!
+
+    assert_not_equal topic.id, reply.parent_id
+    assert_equal topic2.id, reply.parent_id
+
+    assert_equal 0, topic.reload.replies_count
+    assert_equal 1, topic2.reload.replies_count
   end
 
   def test_belongs_to_with_primary_key_counter
@@ -485,11 +509,13 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 0, debate2.reload.replies_count
 
     reply.topic_with_primary_key = debate2
+    reply.save!
 
     assert_equal 0, debate.reload.replies_count
     assert_equal 1, debate2.reload.replies_count
 
     reply.topic_with_primary_key = nil
+    reply.save!
 
     assert_equal 0, debate.reload.replies_count
     assert_equal 0, debate2.reload.replies_count
@@ -516,11 +542,13 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     assert_equal 1, Topic.find(topic2.id).replies.size
 
     reply1.topic = nil
+    reply1.save!
 
     assert_equal 0, Topic.find(topic1.id).replies.size
     assert_equal 0, Topic.find(topic2.id).replies.size
 
     reply1.topic = topic1
+    reply1.save!
 
     assert_equal 1, Topic.find(topic1.id).replies.size
     assert_equal 0, Topic.find(topic2.id).replies.size
@@ -550,7 +578,11 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
 
   def test_belongs_to_counter_after_save
     topic = Topic.create!(title: "monday night")
-    topic.replies.create!(title: "re: monday night", content: "football")
+
+    assert_queries(2) do
+      topic.replies.create!(title: "re: monday night", content: "football")
+    end
+
     assert_equal 1, Topic.find(topic.id)[:replies_count]
 
     topic.save!
@@ -584,8 +616,10 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     debate.touch(time: time)
     debate2.touch(time: time)
 
-    reply.parent_title = "debate"
-    reply.save!
+    assert_queries(3) do
+      reply.parent_title = "debate"
+      reply.save!
+    end
 
     assert_operator debate.reload.updated_at, :>, time
     assert_operator debate2.reload.updated_at, :>, time
@@ -593,7 +627,10 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
     debate.touch(time: time)
     debate2.touch(time: time)
 
-    reply.topic_with_primary_key = debate2
+    assert_queries(3) do
+      reply.topic_with_primary_key = debate2
+      reply.save!
+    end
 
     assert_operator debate.reload.updated_at, :>, time
     assert_operator debate2.reload.updated_at, :>, time
@@ -772,6 +809,7 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
 
     reply = Reply.create(title: "re: zoom", content: "speedy quick!")
     reply.topic = topic
+    reply.save!
 
     assert_equal 1, topic.reload[:replies_count]
     assert_equal 1, topic.replies.size
@@ -827,6 +865,7 @@ class BelongsToAssociationsTest < ActiveRecord::TestCase
 
     silly = SillyReply.create(title: "gaga", content: "boo-boo")
     silly.reply = reply
+    silly.save!
 
     assert_equal 1, reply.reload[:replies_count]
     assert_equal 1, reply.replies.size
diff --git a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
index e717621928..ba2104eb26 100644
--- a/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
+++ b/activerecord/test/cases/associations/cascaded_eager_loading_test.rb
@@ -117,9 +117,8 @@ class CascadedEagerLoadingTest < ActiveRecord::TestCase
   end
 
   def test_eager_association_loading_with_has_many_sti_and_subclasses
-    silly = SillyReply.new(title: "gaga", content: "boo-boo", parent_id: 1)
-    silly.parent_id = 1
-    assert silly.save
+    reply = Reply.new(title: "gaga", content: "boo-boo", parent_id: 1)
+    assert reply.save
 
     topics = Topic.all.merge!(includes: :replies, order: ["topics.id", "replies_topics.id"]).to_a
     assert_no_queries do
diff --git a/activerecord/test/cases/associations/eager_test.rb b/activerecord/test/cases/associations/eager_test.rb
index 5b8d4722af..79b3b4a6ad 100644
--- a/activerecord/test/cases/associations/eager_test.rb
+++ b/activerecord/test/cases/associations/eager_test.rb
@@ -18,6 +18,7 @@ require "models/job"
 require "models/subscriber"
 require "models/subscription"
 require "models/book"
+require "models/citation"
 require "models/developer"
 require "models/computer"
 require "models/project"
@@ -29,6 +30,18 @@ require "models/sponsor"
 require "models/mentor"
 require "models/contract"
 
+class EagerLoadingTooManyIdsTest < ActiveRecord::TestCase
+  fixtures :citations
+
+  def test_preloading_too_many_ids
+    assert_equal Citation.count, Citation.preload(:citations).to_a.size
+  end
+
+  def test_eager_loading_too_may_ids
+    assert_equal Citation.count, Citation.eager_load(:citations).offset(0).size
+  end
+end
+
 class EagerAssociationTest < ActiveRecord::TestCase
   fixtures :posts, :comments, :authors, :essays, :author_addresses, :categories, :categories_posts,
             :companies, :accounts, :tags, :taggings, :people, :readers, :categorizations,
@@ -1571,8 +1584,9 @@ class EagerAssociationTest < ActiveRecord::TestCase
 
   # CollectionProxy#reader is expensive, so the preloader avoids calling it.
   test "preloading has_many_through association avoids calling association.reader" do
-    ActiveRecord::Associations::HasManyAssociation.any_instance.expects(:reader).never
-    Author.preload(:readonly_comments).first!
+    assert_not_called_on_instance_of(ActiveRecord::Associations::HasManyAssociation, :reader) do
+      Author.preload(:readonly_comments).first!
+    end
   end
 
   test "preloading through a polymorphic association doesn't require the association to exist" do
@@ -1604,6 +1618,32 @@ class EagerAssociationTest < ActiveRecord::TestCase
     end
   end
 
+  # Associations::Preloader#preloaders_on works with hash-like objects
+  test "preloading works with an object that responds to :to_hash" do
+    CustomHash = Class.new(Hash)
+
+    assert_nothing_raised do
+      Post.preload(CustomHash.new(comments: [{ author: :essays }])).first
+    end
+  end
+
+  # Associations::Preloader#preloaders_on works with string-like objects
+  test "preloading works with an object that responds to :to_str" do
+    CustomString = Class.new(String)
+
+    assert_nothing_raised do
+      Post.preload(CustomString.new("comments")).first
+    end
+  end
+
+  # Associations::Preloader#preloaders_on does not work with ranges
+  test "preloading fails when Range is passed" do
+    exception = assert_raises(ArgumentError) do
+      Post.preload(1..10).first
+    end
+    assert_equal("1..10 was not recognized for preload", exception.message)
+  end
+
   private
     def find_all_ordered(klass, include = nil)
       klass.order("#{klass.table_name}.#{klass.primary_key}").includes(include).to_a
diff --git a/activerecord/test/cases/associations/extension_test.rb b/activerecord/test/cases/associations/extension_test.rb
index 5eacb5a3d8..aef8f31112 100644
--- a/activerecord/test/cases/associations/extension_test.rb
+++ b/activerecord/test/cases/associations/extension_test.rb
@@ -89,6 +89,6 @@ class AssociationsExtensionsTest < ActiveRecord::TestCase
   private
 
     def extend!(model)
-      ActiveRecord::Associations::Builder::HasMany.define_extensions(model, :association_name) {}
+      ActiveRecord::Associations::Builder::HasMany.define_extensions(model, :association_name) { }
     end
 end
diff --git a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
index f414fbf64b..482302055d 100644
--- a/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_and_belongs_to_many_associations_test.rb
@@ -781,7 +781,7 @@ class HasAndBelongsToManyAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_has_many_through_polymorphic_has_manys_works
-    assert_equal [10, 20].to_set, pirates(:redbeard).treasure_estimates.map(&:price).to_set
+    assert_equal ["$10.00", "$20.00"].to_set, pirates(:redbeard).treasure_estimates.map(&:price).to_set
   end
 
   def test_symbols_as_keys
diff --git a/activerecord/test/cases/associations/has_many_associations_test.rb b/activerecord/test/cases/associations/has_many_associations_test.rb
index 0ca902385a..0b44515e00 100644
--- a/activerecord/test/cases/associations/has_many_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_associations_test.rb
@@ -27,7 +27,6 @@ require "models/categorization"
 require "models/minivan"
 require "models/speedometer"
 require "models/reference"
-require "models/job"
 require "models/college"
 require "models/student"
 require "models/pirate"
@@ -114,7 +113,7 @@ end
 class HasManyAssociationsTest < ActiveRecord::TestCase
   fixtures :accounts, :categories, :companies, :developers, :projects,
            :developers_projects, :topics, :authors, :author_addresses, :comments,
-           :posts, :readers, :taggings, :cars, :jobs, :tags,
+           :posts, :readers, :taggings, :cars, :tags,
            :categorizations, :zines, :interests
 
   def setup
@@ -377,6 +376,27 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal invoice.id, line_item.invoice_id
   end
 
+  class SpecialAuthor < ActiveRecord::Base
+    self.table_name = "authors"
+    has_many :books, class_name: "SpecialBook", foreign_key: :author_id
+  end
+
+  class SpecialBook < ActiveRecord::Base
+    self.table_name = "books"
+
+    belongs_to :author
+    enum read_status: { unread: 0, reading: 2, read: 3, forgotten: nil }
+  end
+
+  def test_association_enum_works_properly
+    author = SpecialAuthor.create!(name: "Test")
+    book = SpecialBook.create!(read_status: "reading")
+    author.books << book
+
+    assert_equal "reading", book.read_status
+    assert_not_equal 0, SpecialAuthor.joins(:books).where(books: { read_status: "reading" }).count
+  end
+
   # When creating objects on the association, we must not do it within a scope (even though it
   # would be convenient), because this would cause that scope to be applied to any callbacks etc.
   def test_build_and_create_should_not_happen_within_scope
@@ -1177,6 +1197,38 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
     assert_equal 2, topic.reload.replies.size
   end
 
+  def test_counter_cache_updates_in_memory_after_update_with_inverse_of_disabled
+    topic = Topic.create!(title: "Zoom-zoom-zoom")
+
+    assert_equal 0, topic.replies_count
+
+    reply1 = Reply.create!(title: "re: zoom", content: "speedy quick!")
+    reply2 = Reply.create!(title: "re: zoom 2", content: "OMG lol!")
+
+    assert_queries(4) do
+      topic.replies << [reply1, reply2]
+    end
+
+    assert_equal 2, topic.replies_count
+    assert_equal 2, topic.reload.replies_count
+  end
+
+  def test_counter_cache_updates_in_memory_after_update_with_inverse_of_enabled
+    category = Category.create!(name: "Counter Cache")
+
+    assert_nil category.categorizations_count
+
+    categorization1 = Categorization.create!
+    categorization2 = Categorization.create!
+
+    assert_queries(4) do
+      category.categorizations << [categorization1, categorization2]
+    end
+
+    assert_equal 2, category.categorizations_count
+    assert_equal 2, category.reload.categorizations_count
+  end
+
   def test_pushing_association_updates_counter_cache
     topic = Topic.order("id ASC").first
     reply = Reply.create!
@@ -2134,21 +2186,29 @@ class HasManyAssociationsTest < ActiveRecord::TestCase
   end
 
   def test_defining_has_many_association_with_delete_all_dependency_lazily_evaluates_target_class
-    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
-    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
-      class DeleteAllModel < ActiveRecord::Base
-        has_many :nonentities, :dependent => :delete_all
-      end
-    EOF
+    assert_not_called_on_instance_of(
+      ActiveRecord::Reflection::AssociationReflection,
+      :class_name,
+    ) do
+      class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+        class DeleteAllModel < ActiveRecord::Base
+          has_many :nonentities, :dependent => :delete_all
+        end
+      EOF
+    end
   end
 
   def test_defining_has_many_association_with_nullify_dependency_lazily_evaluates_target_class
-    ActiveRecord::Reflection::AssociationReflection.any_instance.expects(:class_name).never
-    class_eval(<<-EOF, __FILE__, __LINE__ + 1)
-      class NullifyModel < ActiveRecord::Base
-        has_many :nonentities, :dependent => :nullify
-      end
-    EOF
+    assert_not_called_on_instance_of(
+      ActiveRecord::Reflection::AssociationReflection,
+      :class_name,
+    ) do
+      class_eval(<<-EOF, __FILE__, __LINE__ + 1)
+        class NullifyModel < ActiveRecord::Base
+          has_many :nonentities, :dependent => :nullify
+        end
+      EOF
+    end
   end
 
   def test_attributes_are_being_set_when_initialized_from_has_many_association_with_where_clause
diff --git a/activerecord/test/cases/associations/has_many_through_associations_test.rb b/activerecord/test/cases/associations/has_many_through_associations_test.rb
index d5573b6d02..442f4a93d4 100644
--- a/activerecord/test/cases/associations/has_many_through_associations_test.rb
+++ b/activerecord/test/cases/associations/has_many_through_associations_test.rb
@@ -71,6 +71,15 @@ class HasManyThroughAssociationsTest < ActiveRecord::TestCase
                  club1.members.sort_by(&:id)
   end
 
+  def test_preload_multiple_instances_of_the_same_record
+    club = Club.create!(name: "Aaron cool banana club")
+    Membership.create! club: club, member: Member.create!(name: "Aaron")
+    Membership.create! club: club, member: Member.create!(name: "Bob")
+
+    preloaded_clubs = Club.joins(:memberships).preload(:membership).to_a
+    assert_no_queries { preloaded_clubs.each(&:membership) }
+  end
+
   def test_ordered_has_many_through
     person_prime = Class.new(ActiveRecord::Base) do
       def self.name; "Person"; end
diff --git a/activerecord/test/cases/associations/has_one_associations_test.rb b/activerecord/test/cases/associations/has_one_associations_test.rb
index d7e898a1c0..9eea34d2b9 100644
--- a/activerecord/test/cases/associations/has_one_associations_test.rb
+++ b/activerecord/test/cases/associations/has_one_associations_test.rb
@@ -661,6 +661,8 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     self.table_name = "books"
     belongs_to :author, class_name: "SpecialAuthor"
     has_one :subscription, class_name: "SpecialSupscription", foreign_key: "subscriber_id"
+
+    enum status: [:proposed, :written, :published]
   end
 
   class SpecialAuthor < ActiveRecord::Base
@@ -678,6 +680,7 @@ class HasOneAssociationsTest < ActiveRecord::TestCase
     book = SpecialBook.create!(status: "published")
     author.book = book
 
+    assert_equal "published", book.status
     assert_not_equal 0, SpecialAuthor.joins(:book).where(books: { status: "published" }).count
   end
 
diff --git a/activerecord/test/cases/associations/inverse_associations_test.rb b/activerecord/test/cases/associations/inverse_associations_test.rb
index da3a42e2b5..eb4dc73423 100644
--- a/activerecord/test/cases/associations/inverse_associations_test.rb
+++ b/activerecord/test/cases/associations/inverse_associations_test.rb
@@ -20,6 +20,8 @@ require "models/company"
 require "models/project"
 require "models/author"
 require "models/post"
+require "models/department"
+require "models/hotel"
 
 class AutomaticInverseFindingTests < ActiveRecord::TestCase
   fixtures :ratings, :comments, :cars
@@ -724,6 +726,16 @@ class InversePolymorphicBelongsToTests < ActiveRecord::TestCase
     # fails because Interest does have the correct inverse_of
     assert_raise(ActiveRecord::InverseOfAssociationNotFoundError) { Face.first.polymorphic_man = Interest.first }
   end
+
+  def test_favors_has_one_associations_for_inverse_of
+    inverse_name = Post.reflect_on_association(:author).inverse_of.name
+    assert_equal :post, inverse_name
+  end
+
+  def test_finds_inverse_of_for_plural_associations
+    inverse_name = Department.reflect_on_association(:hotel).inverse_of.name
+    assert_equal :departments, inverse_name
+  end
 end
 
 # NOTE - these tests might not be meaningful, ripped as they were from the parental_control plugin
diff --git a/activerecord/test/cases/associations_test.rb b/activerecord/test/cases/associations_test.rb
index 739eb02e0c..081da95df7 100644
--- a/activerecord/test/cases/associations_test.rb
+++ b/activerecord/test/cases/associations_test.rb
@@ -80,7 +80,7 @@ class AssociationsTest < ActiveRecord::TestCase
   def test_force_reload
     firm = Firm.new("name" => "A New Firm, Inc")
     firm.save
-    firm.clients.each {} # forcing to load all clients
+    firm.clients.each { } # forcing to load all clients
     assert firm.clients.empty?, "New firm shouldn't have client objects"
     assert_equal 0, firm.clients.size, "New firm should have 0 clients"
 
diff --git a/activerecord/test/cases/attributes_test.rb b/activerecord/test/cases/attributes_test.rb
index 3bc56694be..2632aec7ab 100644
--- a/activerecord/test/cases/attributes_test.rb
+++ b/activerecord/test/cases/attributes_test.rb
@@ -148,6 +148,20 @@ module ActiveRecord
       assert_equal 2, klass.new.counter
     end
 
+    test "procs for default values are evaluated even after column_defaults is called" do
+      klass = Class.new(OverloadedType) do
+        @@counter = 0
+        attribute :counter, :integer, default: -> { @@counter += 1 }
+      end
+
+      assert_equal 1, klass.new.counter
+
+      # column_defaults will increment the counter since the proc is called
+      klass.column_defaults
+
+      assert_equal 3, klass.new.counter
+    end
+
     test "procs are memoized before type casting" do
       klass = Class.new(OverloadedType) do
         @@counter = 0
diff --git a/activerecord/test/cases/autosave_association_test.rb b/activerecord/test/cases/autosave_association_test.rb
index ade1f4b44d..db3a58eba9 100644
--- a/activerecord/test/cases/autosave_association_test.rb
+++ b/activerecord/test/cases/autosave_association_test.rb
@@ -14,6 +14,7 @@ require "models/line_item"
 require "models/order"
 require "models/parrot"
 require "models/pirate"
+require "models/project"
 require "models/ship"
 require "models/ship_part"
 require "models/tag"
@@ -558,6 +559,13 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
     assert_equal no_of_clients + 1, Client.count
   end
 
+  def test_parent_should_save_children_record_with_foreign_key_validation_set_in_before_save_callback
+    company = NewlyContractedCompany.new(name: "test")
+
+    assert company.save
+    assert_not_empty company.reload.new_contracts
+  end
+
   def test_parent_should_not_get_saved_with_duplicate_children_records
     assert_no_difference "Reply.count" do
       assert_no_difference "SillyUniqueReply.count" do
@@ -568,7 +576,13 @@ class TestDefaultAutosaveAssociationOnAHasManyAssociation < ActiveRecord::TestCa
         ])
 
         assert_not reply.save
-        assert_not_empty reply.errors
+        assert_equal ["is invalid"], reply.errors[:silly_unique_replies]
+        assert_empty reply.silly_unique_replies.first.errors
+
+        assert_equal(
+          ["has already been taken"],
+          reply.silly_unique_replies.last.errors[:content]
+        )
       end
     end
   end
@@ -1774,3 +1788,21 @@ class TestAutosaveAssociationOnAHasManyAssociationWithInverse < ActiveRecord::Te
     assert_equal 1, comment.post_comments_count
   end
 end
+
+class TestAutosaveAssociationOnAHasManyAssociationDefinedInSubclassWithAcceptsNestedAttributes < ActiveRecord::TestCase
+  def test_should_update_children_when_asssociation_redefined_in_subclass
+    agency = Agency.create!(name: "Agency")
+    valid_project = Project.create!(firm: agency, name: "Initial")
+    agency.update!(
+      "projects_attributes" => {
+        "0" => {
+          "name" => "Updated",
+          "id" => valid_project.id
+        }
+      }
+    )
+    valid_project.reload
+
+    assert_equal "Updated", valid_project.name
+  end
+end
diff --git a/activerecord/test/cases/base_test.rb b/activerecord/test/cases/base_test.rb
index d216fe16fa..09e5517449 100644
--- a/activerecord/test/cases/base_test.rb
+++ b/activerecord/test/cases/base_test.rb
@@ -282,11 +282,13 @@ class BasicsTest < ActiveRecord::TestCase
   end
 
   def test_initialize_with_invalid_attribute
-    Topic.new("title" => "test",
-      "last_read(1i)" => "2005", "last_read(2i)" => "2", "last_read(3i)" => "31")
-  rescue ActiveRecord::MultiparameterAssignmentErrors => ex
+    ex = assert_raise(ActiveRecord::MultiparameterAssignmentErrors) do
+      Topic.new("title" => "test",
+        "written_on(4i)" => "16", "written_on(5i)" => "24", "written_on(6i)" => "00")
+    end
+
     assert_equal(1, ex.errors.size)
-    assert_equal("last_read", ex.errors[0].attribute)
+    assert_equal("written_on", ex.errors[0].attribute)
   end
 
   def test_create_after_initialize_without_block
@@ -853,8 +855,7 @@ class BasicsTest < ActiveRecord::TestCase
     assert_equal company, Company.find(company.id)
   end
 
-  # TODO: extend defaults tests to other databases!
-  if current_adapter?(:PostgreSQLAdapter)
+  if current_adapter?(:PostgreSQLAdapter, :Mysql2Adapter, :SQLite3Adapter)
     def test_default
       with_timezone_config default: :local do
         default = Default.new
@@ -866,7 +867,10 @@ class BasicsTest < ActiveRecord::TestCase
         # char types
         assert_equal "Y", default.char1
         assert_equal "a varchar field", default.char2
-        assert_equal "a text field", default.char3
+        # Mysql text type can't have default value
+        unless current_adapter?(:Mysql2Adapter)
+          assert_equal "a text field", default.char3
+        end
       end
     end
   end
diff --git a/activerecord/test/cases/batches_test.rb b/activerecord/test/cases/batches_test.rb
index c8163901c6..d21218a997 100644
--- a/activerecord/test/cases/batches_test.rb
+++ b/activerecord/test/cases/batches_test.rb
@@ -24,7 +24,7 @@ class EachTest < ActiveRecord::TestCase
 
   def test_each_should_not_return_query_chain_and_execute_only_one_query
     assert_queries(1) do
-      result = Post.find_each(batch_size: 100000) {}
+      result = Post.find_each(batch_size: 100000) { }
       assert_nil result
     end
   end
@@ -155,7 +155,7 @@ class EachTest < ActiveRecord::TestCase
   end
 
   def test_find_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
-    not_a_post = "not a post".dup
+    not_a_post = +"not a post"
     def not_a_post.id; end
     not_a_post.stub(:id, -> { raise StandardError.new("not_a_post had #id called on it") }) do
       assert_nothing_raised do
@@ -183,7 +183,7 @@ class EachTest < ActiveRecord::TestCase
 
   def test_find_in_batches_should_error_on_ignore_the_order
     assert_raise(ArgumentError) do
-      PostWithDefaultScope.find_in_batches(error_on_ignore: true) {}
+      PostWithDefaultScope.find_in_batches(error_on_ignore: true) { }
     end
   end
 
@@ -192,7 +192,7 @@ class EachTest < ActiveRecord::TestCase
     prev = ActiveRecord::Base.error_on_ignored_order
     ActiveRecord::Base.error_on_ignored_order = true
     assert_nothing_raised do
-      PostWithDefaultScope.find_in_batches(error_on_ignore: false) {}
+      PostWithDefaultScope.find_in_batches(error_on_ignore: false) { }
     end
   ensure
     # Set back to default
@@ -204,7 +204,7 @@ class EachTest < ActiveRecord::TestCase
     prev = ActiveRecord::Base.error_on_ignored_order
     ActiveRecord::Base.error_on_ignored_order = true
     assert_raise(ArgumentError) do
-      PostWithDefaultScope.find_in_batches() {}
+      PostWithDefaultScope.find_in_batches() { }
     end
   ensure
     # Set back to default
@@ -213,7 +213,7 @@ class EachTest < ActiveRecord::TestCase
 
   def test_find_in_batches_should_not_error_by_default
     assert_nothing_raised do
-      PostWithDefaultScope.find_in_batches() {}
+      PostWithDefaultScope.find_in_batches() { }
     end
   end
 
@@ -228,7 +228,7 @@ class EachTest < ActiveRecord::TestCase
 
   def test_find_in_batches_should_not_modify_passed_options
     assert_nothing_raised do
-      Post.find_in_batches({ batch_size: 42, start: 1 }.freeze) {}
+      Post.find_in_batches({ batch_size: 42, start: 1 }.freeze) { }
     end
   end
 
@@ -420,7 +420,7 @@ class EachTest < ActiveRecord::TestCase
   end
 
   def test_in_batches_should_not_use_records_after_yielding_them_in_case_original_array_is_modified
-    not_a_post = "not a post".dup
+    not_a_post = +"not a post"
     def not_a_post.id
       raise StandardError.new("not_a_post had #id called on it")
     end
@@ -446,7 +446,7 @@ class EachTest < ActiveRecord::TestCase
 
   def test_in_batches_should_not_modify_passed_options
     assert_nothing_raised do
-      Post.in_batches({ of: 42, start: 1 }.freeze) {}
+      Post.in_batches({ of: 42, start: 1 }.freeze) { }
     end
   end
 
@@ -597,15 +597,15 @@ class EachTest < ActiveRecord::TestCase
         table: table_alias,
         predicate_builder: predicate_builder
       )
-      posts.find_each {}
+      posts.find_each { }
     end
   end
 
   test ".find_each bypasses the query cache for its own queries" do
     Post.cache do
       assert_queries(2) do
-        Post.find_each {}
-        Post.find_each {}
+        Post.find_each { }
+        Post.find_each { }
       end
     end
   end
@@ -624,8 +624,8 @@ class EachTest < ActiveRecord::TestCase
   test ".find_in_batches bypasses the query cache for its own queries" do
     Post.cache do
       assert_queries(2) do
-        Post.find_in_batches {}
-        Post.find_in_batches {}
+        Post.find_in_batches { }
+        Post.find_in_batches { }
       end
     end
   end
@@ -644,8 +644,8 @@ class EachTest < ActiveRecord::TestCase
   test ".in_batches bypasses the query cache for its own queries" do
     Post.cache do
       assert_queries(2) do
-        Post.in_batches {}
-        Post.in_batches {}
+        Post.in_batches { }
+        Post.in_batches { }
       end
     end
   end
diff --git a/activerecord/test/cases/binary_test.rb b/activerecord/test/cases/binary_test.rb
index d5376ece69..58abdb47f7 100644
--- a/activerecord/test/cases/binary_test.rb
+++ b/activerecord/test/cases/binary_test.rb
@@ -12,7 +12,7 @@ unless current_adapter?(:DB2Adapter)
     FIXTURES = %w(flowers.jpg example.log test.txt)
 
     def test_mixed_encoding
-      str = "\x80".dup
+      str = +"\x80"
       str.force_encoding("ASCII-8BIT")
 
       binary = Binary.new name: "いただきます！", data: str
diff --git a/activerecord/test/cases/bind_parameter_test.rb b/activerecord/test/cases/bind_parameter_test.rb
index 91cc49385c..9c1f7aaef2 100644
--- a/activerecord/test/cases/bind_parameter_test.rb
+++ b/activerecord/test/cases/bind_parameter_test.rb
@@ -34,6 +34,12 @@ if ActiveRecord::Base.connection.prepared_statements
         ActiveSupport::Notifications.unsubscribe(@subscription)
       end
 
+      def test_too_many_binds
+        bind_params_length = @connection.send(:bind_params_length)
+        topics = Topic.where(id: (1 .. bind_params_length + 1).to_a)
+        assert_equal Topic.count, topics.count
+      end
+
       def test_bind_from_join_in_subquery
         subquery = Author.joins(:thinking_posts).where(name: "David")
         scope = Author.from(subquery, "authors").where(id: 1)
diff --git a/activerecord/test/cases/callbacks_test.rb b/activerecord/test/cases/callbacks_test.rb
index 253c3099d6..0ea3fb86a6 100644
--- a/activerecord/test/cases/callbacks_test.rb
+++ b/activerecord/test/cases/callbacks_test.rb
@@ -480,7 +480,7 @@ class CallbacksTest < ActiveRecord::TestCase
   def test_before_save_doesnt_allow_on_option
     exception = assert_raises ArgumentError do
       Class.new(ActiveRecord::Base) do
-        before_save(on: :create) {}
+        before_save(on: :create) { }
       end
     end
     assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
@@ -489,7 +489,7 @@ class CallbacksTest < ActiveRecord::TestCase
   def test_around_save_doesnt_allow_on_option
     exception = assert_raises ArgumentError do
       Class.new(ActiveRecord::Base) do
-        around_save(on: :create) {}
+        around_save(on: :create) { }
       end
     end
     assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
@@ -498,7 +498,7 @@ class CallbacksTest < ActiveRecord::TestCase
   def test_after_save_doesnt_allow_on_option
     exception = assert_raises ArgumentError do
       Class.new(ActiveRecord::Base) do
-        after_save(on: :create) {}
+        after_save(on: :create) { }
       end
     end
     assert_equal "Unknown key: :on. Valid keys are: :if, :unless, :prepend", exception.message
diff --git a/activerecord/test/cases/connection_adapters/connection_handler_test.rb b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
index b8e623f17b..5e3447efde 100644
--- a/activerecord/test/cases/connection_adapters/connection_handler_test.rb
+++ b/activerecord/test/cases/connection_adapters/connection_handler_test.rb
@@ -28,13 +28,16 @@ module ActiveRecord
       end
 
       def test_establish_connection_uses_spec_name
+        old_config = ActiveRecord::Base.configurations
         config = { "readonly" => { "adapter" => "sqlite3" } }
-        resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(config)
+        ActiveRecord::Base.configurations = config
+        resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(ActiveRecord::Base.configurations)
         spec =   resolver.spec(:readonly)
         @handler.establish_connection(spec.to_hash)
 
         assert_not_nil @handler.retrieve_connection_pool("readonly")
       ensure
+        ActiveRecord::Base.configurations = old_config
         @handler.remove_connection("readonly")
       end
 
@@ -148,6 +151,30 @@ module ActiveRecord
         ActiveRecord::Base.configurations = @prev_configs
       end
 
+      def test_symbolized_configurations_assignment
+        @prev_configs = ActiveRecord::Base.configurations
+        config = {
+          development: {
+            primary: {
+              adapter: "sqlite3",
+              database: "db/development.sqlite3",
+            },
+          },
+          test: {
+            primary: {
+              adapter: "sqlite3",
+              database: "db/test.sqlite3",
+            },
+          },
+        }
+        ActiveRecord::Base.configurations = config
+        ActiveRecord::Base.configurations.configs_for.each do |db_config|
+          assert_instance_of ActiveRecord::DatabaseConfigurations::HashConfig, db_config
+        end
+      ensure
+        ActiveRecord::Base.configurations = @prev_configs
+      end
+
       def test_retrieve_connection
         assert @handler.retrieve_connection(@spec_name)
       end
diff --git a/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
index 1b64324cc4..06c1c51724 100644
--- a/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
+++ b/activerecord/test/cases/connection_adapters/merge_and_resolve_default_url_config_test.rb
@@ -18,11 +18,14 @@ module ActiveRecord
       end
 
       def resolve_config(config)
-        ActiveRecord::ConnectionHandling::MergeAndResolveDefaultUrlConfig.new(config).resolve
+        configs = ActiveRecord::DatabaseConfigurations.new(config)
+        configs.to_h
       end
 
       def resolve_spec(spec, config)
-        ConnectionSpecification::Resolver.new(resolve_config(config)).resolve(spec)
+        configs = ActiveRecord::DatabaseConfigurations.new(config)
+        resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(configs)
+        resolver.resolve(spec, spec)
       end
 
       def test_resolver_with_database_uri_and_current_env_symbol_key
diff --git a/activerecord/test/cases/connection_management_test.rb b/activerecord/test/cases/connection_management_test.rb
index 0941ee3309..b9b5cc0e28 100644
--- a/activerecord/test/cases/connection_management_test.rb
+++ b/activerecord/test/cases/connection_management_test.rb
@@ -106,7 +106,7 @@ module ActiveRecord
         def middleware(app)
           lambda do |env|
             a, b, c = executor.wrap { app.call(env) }
-            [a, b, Rack::BodyProxy.new(c) {}]
+            [a, b, Rack::BodyProxy.new(c) { }]
           end
         end
     end
diff --git a/activerecord/test/cases/connection_pool_test.rb b/activerecord/test/cases/connection_pool_test.rb
index 9ac03629c3..633d56e479 100644
--- a/activerecord/test/cases/connection_pool_test.rb
+++ b/activerecord/test/cases/connection_pool_test.rb
@@ -91,7 +91,9 @@ module ActiveRecord
       end
 
       def test_full_pool_exception
+        @pool.checkout_timeout = 0.001 # no need to delay test suite by waiting the whole full default timeout
         @pool.size.times { assert @pool.checkout }
+
         assert_raises(ConnectionTimeoutError) do
           @pool.checkout
         end
@@ -109,6 +111,44 @@ module ActiveRecord
         assert_equal connection, t.join.value
       end
 
+      def test_full_pool_blocking_shares_load_interlock
+        @pool.instance_variable_set(:@size, 1)
+
+        load_interlock_latch = Concurrent::CountDownLatch.new
+        connection_latch = Concurrent::CountDownLatch.new
+
+        able_to_get_connection = false
+        able_to_load = false
+
+        thread_with_load_interlock = Thread.new do
+          ActiveSupport::Dependencies.interlock.running do
+            load_interlock_latch.count_down
+            connection_latch.wait
+
+            @pool.with_connection do
+              able_to_get_connection = true
+            end
+          end
+        end
+
+        thread_with_last_connection = Thread.new do
+          @pool.with_connection do
+            connection_latch.count_down
+            load_interlock_latch.wait
+
+            ActiveSupport::Dependencies.interlock.loading do
+              able_to_load = true
+            end
+          end
+        end
+
+        thread_with_load_interlock.join
+        thread_with_last_connection.join
+
+        assert able_to_get_connection
+        assert able_to_load
+      end
+
       def test_removing_releases_latch
         cs = @pool.size.times.map { @pool.checkout }
         t = Thread.new { @pool.checkout }
@@ -156,6 +196,48 @@ module ActiveRecord
         @pool.connections.each { |conn| conn.close if conn.in_use? }
       end
 
+      def test_idle_timeout_configuration
+        @pool.disconnect!
+        spec = ActiveRecord::Base.connection_pool.spec
+        spec.config.merge!(idle_timeout: "0.02")
+        @pool = ConnectionPool.new(spec)
+        idle_conn = @pool.checkout
+        @pool.checkin(idle_conn)
+
+        idle_conn.instance_variable_set(
+          :@idle_since,
+          Concurrent.monotonic_time - 0.01
+        )
+
+        @pool.flush
+        assert_equal 1, @pool.connections.length
+
+        idle_conn.instance_variable_set(
+          :@idle_since,
+          Concurrent.monotonic_time - 0.02
+        )
+
+        @pool.flush
+        assert_equal 0, @pool.connections.length
+      end
+
+      def test_disable_flush
+        @pool.disconnect!
+        spec = ActiveRecord::Base.connection_pool.spec
+        spec.config.merge!(idle_timeout: -5)
+        @pool = ConnectionPool.new(spec)
+        idle_conn = @pool.checkout
+        @pool.checkin(idle_conn)
+
+        idle_conn.instance_variable_set(
+          :@idle_since,
+          Concurrent.monotonic_time - 1
+        )
+
+        @pool.flush
+        assert_equal 1, @pool.connections.length
+      end
+
       def test_flush
         idle_conn = @pool.checkout
         recent_conn = @pool.checkout
@@ -166,9 +248,10 @@ module ActiveRecord
 
         assert_equal 3, @pool.connections.length
 
-        def idle_conn.seconds_idle
-          1000
-        end
+        idle_conn.instance_variable_set(
+          :@idle_since,
+          Concurrent.monotonic_time - 1000
+        )
 
         @pool.flush(30)
 
@@ -578,7 +661,7 @@ module ActiveRecord
           end
 
           stuck_thread = Thread.new do
-            pool.with_connection {}
+            pool.with_connection { }
           end
 
           # wait for stuck_thread to get in queue
diff --git a/activerecord/test/cases/connection_specification/resolver_test.rb b/activerecord/test/cases/connection_specification/resolver_test.rb
index 5b80f16a44..72be14f507 100644
--- a/activerecord/test/cases/connection_specification/resolver_test.rb
+++ b/activerecord/test/cases/connection_specification/resolver_test.rb
@@ -7,11 +7,15 @@ module ActiveRecord
     class ConnectionSpecification
       class ResolverTest < ActiveRecord::TestCase
         def resolve(spec, config = {})
-          Resolver.new(config).resolve(spec)
+          configs = ActiveRecord::DatabaseConfigurations.new(config)
+          resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(configs)
+          resolver.resolve(spec, spec)
         end
 
         def spec(spec, config = {})
-          Resolver.new(config).spec(spec)
+          configs = ActiveRecord::DatabaseConfigurations.new(config)
+          resolver = ConnectionAdapters::ConnectionSpecification::Resolver.new(configs)
+          resolver.spec(spec)
         end
 
         def test_url_invalid_adapter
diff --git a/activerecord/test/cases/core_test.rb b/activerecord/test/cases/core_test.rb
index 6e7ae2efb4..f7fbf3ee8a 100644
--- a/activerecord/test/cases/core_test.rb
+++ b/activerecord/test/cases/core_test.rb
@@ -36,7 +36,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_new
     topic = Topic.new
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0xXXXXXX
@@ -65,7 +65,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_persisted
     topic = topics(:first)
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = <<~PRETTY
       #<Topic:0x\\w+
@@ -93,7 +93,7 @@ class CoreTest < ActiveRecord::TestCase
 
   def test_pretty_print_uninitialized
     topic = Topic.allocate
-    actual = "".dup
+    actual = +""
     PP.pp(topic, StringIO.new(actual))
     expected = "#<Topic:XXXXXX not initialized>\n"
     assert actual.start_with?(expected.split("XXXXXX").first)
@@ -106,7 +106,7 @@ class CoreTest < ActiveRecord::TestCase
         "inspecting topic"
       end
     end
-    actual = "".dup
+    actual = +""
     PP.pp(subtopic.new, StringIO.new(actual))
     assert_equal "inspecting topic\n", actual
   end
diff --git a/activerecord/test/cases/dirty_test.rb b/activerecord/test/cases/dirty_test.rb
index 83cc2aa319..b1ebd20d6b 100644
--- a/activerecord/test/cases/dirty_test.rb
+++ b/activerecord/test/cases/dirty_test.rb
@@ -567,8 +567,6 @@ class DirtyTest < ActiveRecord::TestCase
     assert_not_nil pirate.previous_changes["updated_on"][1]
     assert_not pirate.previous_changes.key?("parrot_id")
     assert_not pirate.previous_changes.key?("created_on")
-  ensure
-    travel_back
   end
 
   class Testings < ActiveRecord::Base; end
@@ -879,6 +877,26 @@ class DirtyTest < ActiveRecord::TestCase
         raise "changed? should be false" if changed?
         raise "has_changes_to_save? should be false" if has_changes_to_save?
         raise "saved_changes? should be true" unless saved_changes?
+        raise "id_in_database should not be nil" if id_in_database.nil?
+      end
+    end
+
+    person = klass.create!(first_name: "Sean")
+    assert_not_predicate person, :changed?
+  end
+
+  test "changed? in around callbacks after yield returns false" do
+    klass = Class.new(ActiveRecord::Base) do
+      self.table_name = "people"
+
+      around_create :check_around
+
+      def check_around
+        yield
+        raise "changed? should be false" if changed?
+        raise "has_changes_to_save? should be false" if has_changes_to_save?
+        raise "saved_changes? should be true" unless saved_changes?
+        raise "id_in_database should not be nil" if id_in_database.nil?
       end
     end
 
diff --git a/activerecord/test/cases/explain_subscriber_test.rb b/activerecord/test/cases/explain_subscriber_test.rb
index 82cc891970..79a0630193 100644
--- a/activerecord/test/cases/explain_subscriber_test.rb
+++ b/activerecord/test/cases/explain_subscriber_test.rb
@@ -40,7 +40,7 @@ if ActiveRecord::Base.connection.supports_explain?
       assert_equal binds, queries[0][1]
     end
 
-    def test_collects_nothing_if_the_statement_is_not_whitelisted
+    def test_collects_nothing_if_the_statement_is_not_explainable
       SUBSCRIBER.finish(nil, nil, name: "SQL", sql: "SHOW max_identifier_length")
       assert_empty queries
     end
diff --git a/activerecord/test/cases/filter_attributes_test.rb b/activerecord/test/cases/filter_attributes_test.rb
new file mode 100644
index 0000000000..af5badd87d
--- /dev/null
+++ b/activerecord/test/cases/filter_attributes_test.rb
@@ -0,0 +1,84 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/admin"
+require "models/admin/user"
+require "models/admin/account"
+require "pp"
+
+class FilterAttributesTest < ActiveRecord::TestCase
+  fixtures :"admin/users", :"admin/accounts"
+
+  setup do
+    @previous_filter_attributes = ActiveRecord::Base.filter_attributes
+    ActiveRecord::Base.filter_attributes = [:name]
+  end
+
+  teardown do
+    ActiveRecord::Base.filter_attributes = @previous_filter_attributes
+  end
+
+  test "filter_attributes" do
+    Admin::User.all.each do |user|
+      assert_includes user.inspect, "name: [FILTERED]"
+      assert_equal 1, user.inspect.scan("[FILTERED]").length
+    end
+
+    Admin::Account.all.each do |account|
+      assert_includes account.inspect, "name: [FILTERED]"
+      assert_equal 1, account.inspect.scan("[FILTERED]").length
+    end
+  end
+
+  test "filter_attributes could be overwritten by models" do
+    Admin::Account.all.each do |account|
+      assert_includes account.inspect, "name: [FILTERED]"
+      assert_equal 1, account.inspect.scan("[FILTERED]").length
+    end
+
+    begin
+      previous_account_filter_attributes = Admin::Account.filter_attributes
+      Admin::Account.filter_attributes = []
+
+      # Above changes should not impact other models
+      Admin::User.all.each do |user|
+        assert_includes user.inspect, "name: [FILTERED]"
+        assert_equal 1, user.inspect.scan("[FILTERED]").length
+      end
+
+      Admin::Account.all.each do |account|
+        assert_not_includes account.inspect, "name: [FILTERED]"
+        assert_equal 0, account.inspect.scan("[FILTERED]").length
+      end
+    ensure
+      Admin::Account.filter_attributes = previous_account_filter_attributes
+    end
+  end
+
+  test "filter_attributes should not filter nil value" do
+    account = Admin::Account.new
+
+    assert_includes account.inspect, "name: nil"
+    assert_not_includes account.inspect, "name: [FILTERED]"
+    assert_equal 0, account.inspect.scan("[FILTERED]").length
+  end
+
+  test "filter_attributes on pretty_print" do
+    user = admin_users(:david)
+    actual = "".dup
+    PP.pp(user, StringIO.new(actual))
+
+    assert_includes actual, "name: [FILTERED]"
+    assert_equal 1, actual.scan("[FILTERED]").length
+  end
+
+  test "filter_attributes on pretty_print should not filter nil value" do
+    user = Admin::User.new
+    actual = "".dup
+    PP.pp(user, StringIO.new(actual))
+
+    assert_includes actual, "name: nil"
+    assert_not_includes actual, "name: [FILTERED]"
+    assert_equal 0, actual.scan("[FILTERED]").length
+  end
+end
diff --git a/activerecord/test/cases/finder_respond_to_test.rb b/activerecord/test/cases/finder_respond_to_test.rb
index 59af4e6961..e0acd30c22 100644
--- a/activerecord/test/cases/finder_respond_to_test.rb
+++ b/activerecord/test/cases/finder_respond_to_test.rb
@@ -12,7 +12,7 @@ class FinderRespondToTest < ActiveRecord::TestCase
   end
 
   def test_should_preserve_normal_respond_to_behaviour_and_respond_to_newly_added_method
-    class << Topic; self; end.send(:define_method, :method_added_for_finder_respond_to_test) {}
+    class << Topic; self; end.send(:define_method, :method_added_for_finder_respond_to_test) { }
     assert_respond_to Topic, :method_added_for_finder_respond_to_test
   ensure
     class << Topic; self; end.send(:remove_method, :method_added_for_finder_respond_to_test)
diff --git a/activerecord/test/cases/finder_test.rb b/activerecord/test/cases/finder_test.rb
index e73c88dd5d..355fb4517f 100644
--- a/activerecord/test/cases/finder_test.rb
+++ b/activerecord/test/cases/finder_test.rb
@@ -371,7 +371,10 @@ class FinderTest < ActiveRecord::TestCase
   end
 
   def test_find_an_empty_array
-    assert_equal [], Topic.find([])
+    empty_array = []
+    result = Topic.find(empty_array)
+    assert_equal [], result
+    assert_not_same empty_array, result
   end
 
   def test_find_doesnt_have_implicit_ordering
diff --git a/activerecord/test/cases/fixtures_test.rb b/activerecord/test/cases/fixtures_test.rb
index c65523d8c1..82ca15b415 100644
--- a/activerecord/test/cases/fixtures_test.rb
+++ b/activerecord/test/cases/fixtures_test.rb
@@ -974,7 +974,7 @@ class TransactionalFixturesOnConnectionNotification < ActiveRecord::TestCase
           connection_id: connection.object_id
         }
 
-        message_bus.instrument("!connection.active_record", payload) {}
+        message_bus.instrument("!connection.active_record", payload) { }
       end
     end
 end
@@ -1344,3 +1344,19 @@ class SameNameDifferentDatabaseFixturesTest < ActiveRecord::TestCase
     assert_kind_of OtherDog, other_dogs(:lassie)
   end
 end
+
+class NilFixturePathTest < ActiveRecord::TestCase
+  test "raises an error when all fixtures loaded" do
+    error = assert_raises(StandardError) do
+      TestCase = Class.new(ActiveRecord::TestCase)
+      TestCase.class_eval do
+        self.fixture_path = nil
+        fixtures :all
+      end
+    end
+    assert_equal <<~MSG.squish, error.message
+      No fixture path found.
+      Please set `NilFixturePathTest::TestCase.fixture_path`.
+    MSG
+  end
+end
diff --git a/activerecord/test/cases/helper.rb b/activerecord/test/cases/helper.rb
index 66f11fe5bd..68be685e4b 100644
--- a/activerecord/test/cases/helper.rb
+++ b/activerecord/test/cases/helper.rb
@@ -183,5 +183,3 @@ module InTimeZone
       ActiveRecord::Base.time_zone_aware_attributes = old_tz
     end
 end
-
-require "mocha/minitest" # FIXME: stop using mocha
diff --git a/activerecord/test/cases/invertible_migration_test.rb b/activerecord/test/cases/invertible_migration_test.rb
index 363beb4780..6cf17ac15d 100644
--- a/activerecord/test/cases/invertible_migration_test.rb
+++ b/activerecord/test/cases/invertible_migration_test.rb
@@ -22,6 +22,14 @@ module ActiveRecord
       end
     end
 
+    class InvertibleTransactionMigration < InvertibleMigration
+      def change
+        transaction do
+          super
+        end
+      end
+    end
+
     class InvertibleRevertMigration < SilentMigration
       def change
         revert do
@@ -271,6 +279,14 @@ module ActiveRecord
       assert_not revert.connection.table_exists?("horses")
     end
 
+    def test_migrate_revert_transaction
+      migration = InvertibleTransactionMigration.new
+      migration.migrate :up
+      assert migration.connection.table_exists?("horses")
+      migration.migrate :down
+      assert_not migration.connection.table_exists?("horses")
+    end
+
     def test_migrate_revert_change_column_default
       migration1 = ChangeColumnDefault1.new
       migration1.migrate(:up)
diff --git a/activerecord/test/cases/legacy_configurations_test.rb b/activerecord/test/cases/legacy_configurations_test.rb
new file mode 100644
index 0000000000..c36feb5116
--- /dev/null
+++ b/activerecord/test/cases/legacy_configurations_test.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class LegacyConfigurationsTest < ActiveRecord::TestCase
+    def test_can_turn_configurations_into_a_hash
+      assert ActiveRecord::Base.configurations.to_h.is_a?(Hash), "expected to be a hash but was not."
+      assert_equal ["arunit", "arunit2", "arunit_without_prepared_statements"].sort, ActiveRecord::Base.configurations.to_h.keys.sort
+    end
+
+    def test_each_is_deprecated
+      assert_deprecated do
+        ActiveRecord::Base.configurations.each do |db_config|
+          assert_equal "primary", db_config.spec_name
+        end
+      end
+    end
+
+    def test_first_is_deprecated
+      assert_deprecated do
+        db_config = ActiveRecord::Base.configurations.first
+        assert_equal "arunit", db_config.env_name
+        assert_equal "primary", db_config.spec_name
+      end
+    end
+
+    def test_fetch_is_deprecated
+      assert_deprecated do
+        db_config = ActiveRecord::Base.configurations.fetch("arunit").first
+        assert_equal "arunit", db_config.env_name
+        assert_equal "primary", db_config.spec_name
+      end
+    end
+
+    def test_values_are_deprecated
+      config_hashes = ActiveRecord::Base.configurations.configurations.map(&:config)
+      assert_deprecated do
+        assert_equal config_hashes, ActiveRecord::Base.configurations.values
+      end
+    end
+  end
+end
diff --git a/activerecord/test/cases/log_subscriber_test.rb b/activerecord/test/cases/log_subscriber_test.rb
index f0126fdb0d..ae2597adc8 100644
--- a/activerecord/test/cases/log_subscriber_test.rb
+++ b/activerecord/test/cases/log_subscriber_test.rb
@@ -44,6 +44,7 @@ class LogSubscriberTest < ActiveRecord::TestCase
   def setup
     @old_logger = ActiveRecord::Base.logger
     Developer.primary_key
+    ActiveRecord::Base.connection.materialize_transactions
     super
     ActiveRecord::LogSubscriber.attach_to(:active_record)
   end
diff --git a/activerecord/test/cases/migration/change_table_test.rb b/activerecord/test/cases/migration/change_table_test.rb
index 034bf32165..c108d372d1 100644
--- a/activerecord/test/cases/migration/change_table_test.rb
+++ b/activerecord/test/cases/migration/change_table_test.rb
@@ -164,6 +164,14 @@ module ActiveRecord
         end
       end
 
+      def test_column_creates_column_with_index
+        with_change_table do |t|
+          @connection.expect :add_column, nil, [:delete_me, :bar, :integer, {}]
+          @connection.expect :add_index, nil, [:delete_me, :bar, {}]
+          t.column :bar, :integer, index: true
+        end
+      end
+
       def test_index_creates_index
         with_change_table do |t|
           @connection.expect :add_index, nil, [:delete_me, :bar, {}]
diff --git a/activerecord/test/cases/migration/command_recorder_test.rb b/activerecord/test/cases/migration/command_recorder_test.rb
index 3a11bb081b..01f8628fc5 100644
--- a/activerecord/test/cases/migration/command_recorder_test.rb
+++ b/activerecord/test/cases/migration/command_recorder_test.rb
@@ -117,13 +117,13 @@ module ActiveRecord
       end
 
       def test_invert_create_table_with_options_and_block
-        block = Proc.new {}
+        block = Proc.new { }
         drop_table = @recorder.inverse_of :create_table, [:people_reminders, id: false], &block
         assert_equal [:drop_table, [:people_reminders, id: false], block], drop_table
       end
 
       def test_invert_drop_table
-        block = Proc.new {}
+        block = Proc.new { }
         create_table = @recorder.inverse_of :drop_table, [:people_reminders, id: false], &block
         assert_equal [:create_table, [:people_reminders, id: false], block], create_table
       end
@@ -145,7 +145,7 @@ module ActiveRecord
       end
 
       def test_invert_drop_join_table
-        block = Proc.new {}
+        block = Proc.new { }
         create_join_table = @recorder.inverse_of :drop_join_table, [:musics, :artists, table_name: :catalog], &block
         assert_equal [:create_join_table, [:musics, :artists, table_name: :catalog], block], create_join_table
       end
@@ -329,11 +329,24 @@ module ActiveRecord
         assert_equal [:add_foreign_key, [:dogs, :people, primary_key: "person_id"]], enable
       end
 
+      def test_invert_remove_foreign_key_with_primary_key_and_to_table_in_options
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, to_table: :people, primary_key: "uuid"]
+        assert_equal [:add_foreign_key, [:dogs, :people, primary_key: "uuid"]], enable
+      end
+
       def test_invert_remove_foreign_key_with_on_delete_on_update
         enable = @recorder.inverse_of :remove_foreign_key, [:dogs, :people, on_delete: :nullify, on_update: :cascade]
         assert_equal [:add_foreign_key, [:dogs, :people, on_delete: :nullify, on_update: :cascade]], enable
       end
 
+      def test_invert_remove_foreign_key_with_to_table_in_options
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, to_table: :people]
+        assert_equal [:add_foreign_key, [:dogs, :people]], enable
+
+        enable = @recorder.inverse_of :remove_foreign_key, [:dogs, to_table: :people, column: :owner_id]
+        assert_equal [:add_foreign_key, [:dogs, :people, column: :owner_id]], enable
+      end
+
       def test_invert_remove_foreign_key_is_irreversible_without_to_table
         assert_raises ActiveRecord::IrreversibleMigration do
           @recorder.inverse_of :remove_foreign_key, [:dogs, column: "owner_id"]
@@ -347,6 +360,16 @@ module ActiveRecord
           @recorder.inverse_of :remove_foreign_key, [:dogs]
         end
       end
+
+      def test_invert_transaction_with_irreversible_inside_is_irreversible
+        assert_raises(ActiveRecord::IrreversibleMigration) do
+          @recorder.revert do
+            @recorder.transaction do
+              @recorder.execute "some sql"
+            end
+          end
+        end
+      end
     end
   end
 end
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
index 69a50674af..017ee7951e 100644
--- a/activerecord/test/cases/migration/compatibility_test.rb
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -127,6 +127,20 @@ module ActiveRecord
         assert_match(/LegacyMigration < ActiveRecord::Migration\[4\.2\]/, e.message)
       end
 
+      def test_legacy_migrations_not_raise_exception_on_reverting_transaction
+        migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def change
+            transaction do
+              execute "select 1"
+            end
+          end
+        }.new
+
+        assert_nothing_raised do
+          migration.migrate(:down)
+        end
+      end
+
       if current_adapter?(:PostgreSQLAdapter)
         class Testing < ActiveRecord::Base
         end
diff --git a/activerecord/test/cases/migration/foreign_key_test.rb b/activerecord/test/cases/migration/foreign_key_test.rb
index c471dd1106..bb233fbf74 100644
--- a/activerecord/test/cases/migration/foreign_key_test.rb
+++ b/activerecord/test/cases/migration/foreign_key_test.rb
@@ -53,16 +53,49 @@ if ActiveRecord::Base.connection.supports_foreign_keys_in_create?
         end
 
         def test_change_column_of_parent_table
-          foreign_keys = ActiveRecord::Base.connection.foreign_keys("astronauts")
           rocket = Rocket.create!(name: "myrocket")
           rocket.astronauts << Astronaut.create!
 
           @connection.change_column_null :rockets, :name, false
 
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "myrocket", Rocket.first.name
+          assert_equal "astronauts", fk.from_table
+          assert_equal "rockets", fk.to_table
+        end
+
+        def test_rename_column_of_child_table
+          rocket = Rocket.create!(name: "myrocket")
+          rocket.astronauts << Astronaut.create!
+
+          @connection.rename_column :astronauts, :name, :astronaut_name
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
+          fk = foreign_keys.first
+          assert_equal "myrocket", Rocket.first.name
+          assert_equal "astronauts", fk.from_table
+          assert_equal "rockets", fk.to_table
+        end
+
+        def test_rename_reference_column_of_child_table
+          rocket = Rocket.create!(name: "myrocket")
+          rocket.astronauts << Astronaut.create!
+
+          @connection.rename_column :astronauts, :rocket_id, :new_rocket_id
+
+          foreign_keys = @connection.foreign_keys("astronauts")
+          assert_equal 1, foreign_keys.size
+
           fk = foreign_keys.first
           assert_equal "myrocket", Rocket.first.name
           assert_equal "astronauts", fk.from_table
           assert_equal "rockets", fk.to_table
+          assert_equal "new_rocket_id", fk.options[:column]
         end
       end
     end
diff --git a/activerecord/test/cases/migration/pending_migrations_test.rb b/activerecord/test/cases/migration/pending_migrations_test.rb
index dedb5ea502..119bfd372a 100644
--- a/activerecord/test/cases/migration/pending_migrations_test.rb
+++ b/activerecord/test/cases/migration/pending_migrations_test.rb
@@ -25,7 +25,7 @@ module ActiveRecord
           ActiveRecord::Base.connection.drop_table "schema_migrations", if_exists: true
 
           assert_raises ActiveRecord::PendingMigrationError do
-            CheckPending.new(Proc.new {}).call({})
+            CheckPending.new(Proc.new { }).call({})
           end
         end
 
@@ -34,7 +34,7 @@ module ActiveRecord
           migrator = Base.connection.migration_context
           capture(:stdout) { migrator.migrate }
 
-          assert_nil CheckPending.new(Proc.new {}).call({})
+          assert_nil CheckPending.new(Proc.new { }).call({})
         end
       end
     end
diff --git a/activerecord/test/cases/migration_test.rb b/activerecord/test/cases/migration_test.rb
index d1292dc53d..5d060c8899 100644
--- a/activerecord/test/cases/migration_test.rb
+++ b/activerecord/test/cases/migration_test.rb
@@ -87,7 +87,6 @@ class MigrationTest < ActiveRecord::TestCase
 
   def test_migrator_versions
     migrations_path = MIGRATIONS_ROOT + "/valid"
-    old_path = ActiveRecord::Migrator.migrations_paths
     migrator = ActiveRecord::MigrationContext.new(migrations_path)
 
     migrator.up
@@ -100,24 +99,18 @@ class MigrationTest < ActiveRecord::TestCase
 
     ActiveRecord::SchemaMigration.create!(version: 3)
     assert_equal true, migrator.needs_migration?
-  ensure
-    ActiveRecord::MigrationContext.new(old_path)
   end
 
   def test_migration_detection_without_schema_migration_table
     ActiveRecord::Base.connection.drop_table "schema_migrations", if_exists: true
 
     migrations_path = MIGRATIONS_ROOT + "/valid"
-    old_path = ActiveRecord::Migrator.migrations_paths
     migrator = ActiveRecord::MigrationContext.new(migrations_path)
 
     assert_equal true, migrator.needs_migration?
-  ensure
-    ActiveRecord::MigrationContext.new(old_path)
   end
 
   def test_any_migrations
-    old_path = ActiveRecord::Migrator.migrations_paths
     migrator = ActiveRecord::MigrationContext.new(MIGRATIONS_ROOT + "/valid")
 
     assert_predicate migrator, :any_migrations?
@@ -125,8 +118,6 @@ class MigrationTest < ActiveRecord::TestCase
     migrator_empty = ActiveRecord::MigrationContext.new(MIGRATIONS_ROOT + "/empty")
 
     assert_not_predicate migrator_empty, :any_migrations?
-  ensure
-    ActiveRecord::MigrationContext.new(old_path)
   end
 
   def test_migration_version
@@ -393,7 +384,6 @@ class MigrationTest < ActiveRecord::TestCase
   def test_internal_metadata_stores_environment
     current_env     = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
     migrations_path = MIGRATIONS_ROOT + "/valid"
-    old_path        = ActiveRecord::Migrator.migrations_paths
     migrator = ActiveRecord::MigrationContext.new(migrations_path)
 
     migrator.up
@@ -410,7 +400,6 @@ class MigrationTest < ActiveRecord::TestCase
     migrator.up
     assert_equal new_env, ActiveRecord::InternalMetadata[:environment]
   ensure
-    migrator = ActiveRecord::MigrationContext.new(old_path)
     ENV["RAILS_ENV"] = original_rails_env
     ENV["RACK_ENV"]  = original_rack_env
     migrator.up
@@ -422,16 +411,12 @@ class MigrationTest < ActiveRecord::TestCase
 
     current_env     = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
     migrations_path = MIGRATIONS_ROOT + "/valid"
-    old_path        = ActiveRecord::Migrator.migrations_paths
 
     current_env = ActiveRecord::ConnectionHandling::DEFAULT_ENV.call
     migrator = ActiveRecord::MigrationContext.new(migrations_path)
     migrator.up
     assert_equal current_env, ActiveRecord::InternalMetadata[:environment]
     assert_equal "bar", ActiveRecord::InternalMetadata[:foo]
-  ensure
-    migrator = ActiveRecord::MigrationContext.new(old_path)
-    migrator.up
   end
 
   def test_proper_table_name_on_migration
@@ -793,12 +778,20 @@ if ActiveRecord::Base.connection.supports_bulk_alter?
     end
 
     def test_adding_multiple_columns
-      assert_queries(1) do
+      classname = ActiveRecord::Base.connection.class.name[/[^:]*$/]
+      expected_query_count = {
+        "Mysql2Adapter"     => 1,
+        "PostgreSQLAdapter" => 2, # one for bulk change, one for comment
+      }.fetch(classname) {
+        raise "need an expected query count for #{classname}"
+      }
+
+      assert_queries(expected_query_count) do
         with_bulk_change_table do |t|
           t.column :name, :string
           t.string :qualification, :experience
           t.integer :age, default: 0
-          t.date :birthdate
+          t.date :birthdate, comment: "This is a comment"
           t.timestamps null: true
         end
       end
@@ -806,6 +799,7 @@ if ActiveRecord::Base.connection.supports_bulk_alter?
       assert_equal 8, columns.size
       [:name, :qualification, :experience].each { |s| assert_equal :string, column(s).type }
       assert_equal "0", column(:age).default
+      assert_equal "This is a comment", column(:birthdate).comment
     end
 
     def test_removing_columns
@@ -1150,7 +1144,7 @@ class CopyMigrationsTest < ActiveRecord::TestCase
   def test_check_pending_with_stdlib_logger
     old, ActiveRecord::Base.logger = ActiveRecord::Base.logger, ::Logger.new($stdout)
     quietly do
-      assert_nothing_raised { ActiveRecord::Migration::CheckPending.new(Proc.new {}).call({}) }
+      assert_nothing_raised { ActiveRecord::Migration::CheckPending.new(Proc.new { }).call({}) }
     end
   ensure
     ActiveRecord::Base.logger = old
diff --git a/activerecord/test/cases/migrator_test.rb b/activerecord/test/cases/migrator_test.rb
index 873455cf67..30e199f1c5 100644
--- a/activerecord/test/cases/migrator_test.rb
+++ b/activerecord/test/cases/migrator_test.rb
@@ -100,7 +100,6 @@ class MigratorTest < ActiveRecord::TestCase
   def test_finds_migrations_in_subdirectories
     migrations = ActiveRecord::MigrationContext.new(MIGRATIONS_ROOT + "/valid_with_subdirectories").migrations
 
-
     [[1, "ValidPeopleHaveLastNames"], [2, "WeNeedReminders"], [3, "InnocentJointable"]].each_with_index do |pair, i|
       assert_equal migrations[i].version, pair.first
       assert_equal migrations[i].name, pair.last
diff --git a/activerecord/test/cases/nested_attributes_test.rb b/activerecord/test/cases/nested_attributes_test.rb
index aa519fd332..bb1c1ea17d 100644
--- a/activerecord/test/cases/nested_attributes_test.rb
+++ b/activerecord/test/cases/nested_attributes_test.rb
@@ -217,6 +217,18 @@ class TestNestedAttributesInGeneral < ActiveRecord::TestCase
     mean_pirate.parrot_attributes = { name: "James" }
     assert_equal "James", mean_pirate.parrot.name
   end
+
+  def test_should_not_create_duplicates_with_create_with
+    Man.accepts_nested_attributes_for(:interests)
+
+    assert_difference("Interest.count", 1) do
+      Man.create_with(
+        interests_attributes: [{ topic: "Pirate king" }]
+      ).find_or_create_by!(
+        name: "Monkey D. Luffy"
+      )
+    end
+  end
 end
 
 class TestNestedAttributesOnAHasOneAssociation < ActiveRecord::TestCase
diff --git a/activerecord/test/cases/persistence_test.rb b/activerecord/test/cases/persistence_test.rb
index 7348a22dd3..8073cabae6 100644
--- a/activerecord/test/cases/persistence_test.rb
+++ b/activerecord/test/cases/persistence_test.rb
@@ -13,90 +13,15 @@ require "models/developer"
 require "models/computer"
 require "models/project"
 require "models/minimalistic"
-require "models/warehouse_thing"
 require "models/parrot"
 require "models/minivan"
-require "models/owner"
 require "models/person"
-require "models/pet"
 require "models/ship"
-require "models/toy"
 require "models/admin"
 require "models/admin/user"
-require "rexml/document"
 
 class PersistenceTest < ActiveRecord::TestCase
-  fixtures :topics, :companies, :developers, :projects, :computers, :accounts, :minimalistics, "warehouse-things", :authors, :author_addresses, :categorizations, :categories, :posts, :minivans, :pets, :toys
-
-  # Oracle UPDATE does not support ORDER BY
-  unless current_adapter?(:OracleAdapter)
-    def test_update_all_ignores_order_without_limit_from_association
-      author = authors(:david)
-      assert_nothing_raised do
-        assert_equal author.posts_with_comments_and_categories.length, author.posts_with_comments_and_categories.update_all([ "body = ?", "bulk update!" ])
-      end
-    end
-
-    def test_update_all_doesnt_ignore_order
-      assert_equal authors(:david).id + 1, authors(:mary).id # make sure there is going to be a duplicate PK error
-      test_update_with_order_succeeds = lambda do |order|
-        begin
-          Author.order(order).update_all("id = id + 1")
-        rescue ActiveRecord::ActiveRecordError
-          false
-        end
-      end
-
-      if test_update_with_order_succeeds.call("id DESC")
-        assert_not test_update_with_order_succeeds.call("id ASC") # test that this wasn't a fluke and using an incorrect order results in an exception
-      else
-        # test that we're failing because the current Arel's engine doesn't support UPDATE ORDER BY queries is using subselects instead
-        assert_sql(/\AUPDATE .+ \(SELECT .* ORDER BY id DESC\)\z/i) do
-          test_update_with_order_succeeds.call("id DESC")
-        end
-      end
-    end
-
-    def test_update_all_with_order_and_limit_updates_subset_only
-      author = authors(:david)
-      limited_posts = author.posts_sorted_by_id_limited
-      assert_equal 1, limited_posts.size
-      assert_equal 2, limited_posts.limit(2).size
-      assert_equal 1, limited_posts.update_all([ "body = ?", "bulk update!" ])
-      assert_equal "bulk update!", posts(:welcome).body
-      assert_not_equal "bulk update!", posts(:thinking).body
-    end
-
-    def test_update_all_with_order_and_limit_and_offset_updates_subset_only
-      author = authors(:david)
-      limited_posts = author.posts_sorted_by_id_limited.offset(1)
-      assert_equal 1, limited_posts.size
-      assert_equal 2, limited_posts.limit(2).size
-      assert_equal 1, limited_posts.update_all([ "body = ?", "bulk update!" ])
-      assert_equal "bulk update!", posts(:thinking).body
-      assert_not_equal "bulk update!", posts(:welcome).body
-    end
-
-    def test_delete_all_with_order_and_limit_deletes_subset_only
-      author = authors(:david)
-      limited_posts = Post.where(author: author).order(:id).limit(1)
-      assert_equal 1, limited_posts.size
-      assert_equal 2, limited_posts.limit(2).size
-      assert_equal 1, limited_posts.delete_all
-      assert_raise(ActiveRecord::RecordNotFound) { posts(:welcome) }
-      assert posts(:thinking)
-    end
-
-    def test_delete_all_with_order_and_limit_and_offset_deletes_subset_only
-      author = authors(:david)
-      limited_posts = Post.where(author: author).order(:id).limit(1).offset(1)
-      assert_equal 1, limited_posts.size
-      assert_equal 2, limited_posts.limit(2).size
-      assert_equal 1, limited_posts.delete_all
-      assert_raise(ActiveRecord::RecordNotFound) { posts(:thinking) }
-      assert posts(:welcome)
-    end
-  end
+  fixtures :topics, :companies, :developers, :accounts, :minimalistics, :authors, :author_addresses, :posts, :minivans
 
   def test_update_many
     topic_data = { 1 => { "content" => "1 updated" }, 2 => { "content" => "2 updated" } }
@@ -145,34 +70,6 @@ class PersistenceTest < ActiveRecord::TestCase
     assert_equal Topic.count, Topic.delete_all
   end
 
-  def test_delete_all_with_joins_and_where_part_is_hash
-    pets = Pet.joins(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.delete_all
-  end
-
-  def test_delete_all_with_joins_and_where_part_is_not_hash
-    pets = Pet.joins(:toys).where("toys.name = ?", "Bone")
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.delete_all
-  end
-
-  def test_delete_all_with_left_joins
-    pets = Pet.left_joins(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.delete_all
-  end
-
-  def test_delete_all_with_includes
-    pets = Pet.includes(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.delete_all
-  end
-
   def test_increment_attribute
     assert_equal 50, accounts(:signals37).credit_limit
     accounts(:signals37).increment! :credit_limit
@@ -230,16 +127,9 @@ class PersistenceTest < ActiveRecord::TestCase
     assert_operator previously_written_on, :<, topic.written_on
   end
 
-  def test_destroy_all
-    conditions = "author_name = 'Mary'"
-    topics_by_mary = Topic.all.merge!(where: conditions, order: "id").to_a
-    assert_not_empty topics_by_mary
-
-    assert_difference("Topic.count", -topics_by_mary.size) do
-      destroyed = Topic.where(conditions).destroy_all.sort_by(&:id)
-      assert_equal topics_by_mary, destroyed
-      assert destroyed.all?(&:frozen?), "destroyed topics should be frozen"
-    end
+  def test_increment_with_no_arg
+    topic = topics(:first)
+    assert_raises(ArgumentError) { topic.increment! }
   end
 
   def test_destroy_many
@@ -638,32 +528,6 @@ class PersistenceTest < ActiveRecord::TestCase
     assert_nil Topic.find(2).last_read
   end
 
-  def test_update_all_with_joins
-    pets = Pet.joins(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.update_all(name: "Bob")
-  end
-
-  def test_update_all_with_left_joins
-    pets = Pet.left_joins(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.update_all(name: "Bob")
-  end
-
-  def test_update_all_with_includes
-    pets = Pet.includes(:toys).where(toys: { name: "Bone" })
-
-    assert_equal true, pets.exists?
-    assert_equal pets.count, pets.update_all(name: "Bob")
-  end
-
-  def test_update_all_with_non_standard_table_name
-    assert_equal 1, WarehouseThing.where(id: 1).update_all(["value = ?", 0])
-    assert_equal 0, WarehouseThing.find(1).value
-  end
-
   def test_delete_new_record
     client = Client.new(name: "37signals")
     client.delete
@@ -1185,21 +1049,19 @@ class PersistenceTest < ActiveRecord::TestCase
     ActiveRecord::Base.connection.disable_query_cache!
   end
 
-  class SaveTest < ActiveRecord::TestCase
-    def test_save_touch_false
-      pet = Pet.create!(
-        name: "Bob",
-        created_at: 1.day.ago,
-        updated_at: 1.day.ago)
+  def test_save_touch_false
+    parrot = Parrot.create!(
+      name: "Bob",
+      created_at: 1.day.ago,
+      updated_at: 1.day.ago)
 
-      created_at = pet.created_at
-      updated_at = pet.updated_at
+    created_at = parrot.created_at
+    updated_at = parrot.updated_at
 
-      pet.name = "Barb"
-      pet.save!(touch: false)
-      assert_equal pet.created_at, created_at
-      assert_equal pet.updated_at, updated_at
-    end
+    parrot.name = "Barb"
+    parrot.save!(touch: false)
+    assert_equal parrot.created_at, created_at
+    assert_equal parrot.updated_at, updated_at
   end
 
   def test_reset_column_information_resets_children
diff --git a/activerecord/test/cases/query_cache_test.rb b/activerecord/test/cases/query_cache_test.rb
index 69be091869..3eb4e04cb7 100644
--- a/activerecord/test/cases/query_cache_test.rb
+++ b/activerecord/test/cases/query_cache_test.rb
@@ -55,16 +55,6 @@ class QueryCacheTest < ActiveRecord::TestCase
     assert_cache :off
   end
 
-  private def with_temporary_connection_pool
-    old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
-    new_pool = ActiveRecord::ConnectionAdapters::ConnectionPool.new ActiveRecord::Base.connection_pool.spec
-    ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = new_pool
-
-    yield
-  ensure
-    ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = old_pool
-  end
-
   def test_query_cache_across_threads
     with_temporary_connection_pool do
       begin
@@ -495,6 +485,17 @@ class QueryCacheTest < ActiveRecord::TestCase
   end
 
   private
+
+    def with_temporary_connection_pool
+      old_pool = ActiveRecord::Base.connection_handler.retrieve_connection_pool(ActiveRecord::Base.connection_specification_name)
+      new_pool = ActiveRecord::ConnectionAdapters::ConnectionPool.new ActiveRecord::Base.connection_pool.spec
+      ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = new_pool
+
+      yield
+    ensure
+      ActiveRecord::Base.connection_handler.send(:owner_to_pool)["primary"] = old_pool
+    end
+
     def middleware(&app)
       executor = Class.new(ActiveSupport::Executor)
       ActiveRecord::QueryCache.install_executor_hooks executor
diff --git a/activerecord/test/cases/reaper_test.rb b/activerecord/test/cases/reaper_test.rb
index b034fe3e3b..b630f782bc 100644
--- a/activerecord/test/cases/reaper_test.rb
+++ b/activerecord/test/cases/reaper_test.rb
@@ -61,9 +61,9 @@ module ActiveRecord
 
       def test_reaping_frequency_configuration
         spec = ActiveRecord::Base.connection_pool.spec.dup
-        spec.config[:reaping_frequency] = 100
+        spec.config[:reaping_frequency] = "10.01"
         pool = ConnectionPool.new spec
-        assert_equal 100, pool.reaper.frequency
+        assert_equal 10.01, pool.reaper.frequency
       end
 
       def test_connection_pool_starts_reaper
diff --git a/activerecord/test/cases/relation/delegation_test.rb b/activerecord/test/cases/relation/delegation_test.rb
index 3f3d41980c..a8030c2d64 100644
--- a/activerecord/test/cases/relation/delegation_test.rb
+++ b/activerecord/test/cases/relation/delegation_test.rb
@@ -5,7 +5,7 @@ require "models/post"
 require "models/comment"
 
 module ActiveRecord
-  module DelegationWhitelistTests
+  module ArrayDelegationTests
     ARRAY_DELEGATES = [
       :+, :-, :|, :&, :[], :shuffle,
       :all?, :collect, :compact, :detect, :each, :each_cons, :each_with_index,
@@ -38,7 +38,7 @@ module ActiveRecord
   end
 
   class DelegationAssociationTest < ActiveRecord::TestCase
-    include DelegationWhitelistTests
+    include ArrayDelegationTests
     include DeprecatedArelDelegationTests
 
     def target
@@ -47,7 +47,7 @@ module ActiveRecord
   end
 
   class DelegationRelationTest < ActiveRecord::TestCase
-    include DelegationWhitelistTests
+    include ArrayDelegationTests
     include DeprecatedArelDelegationTests
 
     def target
diff --git a/activerecord/test/cases/relation/delete_all_test.rb b/activerecord/test/cases/relation/delete_all_test.rb
new file mode 100644
index 0000000000..446d7621ea
--- /dev/null
+++ b/activerecord/test/cases/relation/delete_all_test.rb
@@ -0,0 +1,104 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/post"
+require "models/pet"
+require "models/toy"
+
+class DeleteAllTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :posts, :pets, :toys
+
+  def test_destroy_all
+    davids = Author.where(name: "David")
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert_predicate davids, :loaded?
+
+    assert_difference("Author.count", -1) do
+      destroyed = davids.destroy_all
+      assert_equal [authors(:david)], destroyed
+      assert_predicate destroyed.first, :frozen?
+    end
+
+    assert_equal [], davids.to_a
+    assert_predicate davids, :loaded?
+  end
+
+  def test_delete_all
+    davids = Author.where(name: "David")
+
+    assert_difference("Author.count", -1) { davids.delete_all }
+    assert_not_predicate davids, :loaded?
+  end
+
+  def test_delete_all_loaded
+    davids = Author.where(name: "David")
+
+    # Force load
+    assert_equal [authors(:david)], davids.to_a
+    assert_predicate davids, :loaded?
+
+    assert_difference("Author.count", -1) { davids.delete_all }
+
+    assert_equal [], davids.to_a
+    assert_predicate davids, :loaded?
+  end
+
+  def test_delete_all_with_unpermitted_relation_raises_error
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.distinct.delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.group(:name).delete_all }
+    assert_raises(ActiveRecord::ActiveRecordError) { Author.having("SUM(id) < 3").delete_all }
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_hash
+    pets = Pet.joins(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.delete_all
+  end
+
+  def test_delete_all_with_joins_and_where_part_is_not_hash
+    pets = Pet.joins(:toys).where("toys.name = ?", "Bone")
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.delete_all
+  end
+
+  def test_delete_all_with_left_joins
+    pets = Pet.left_joins(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.delete_all
+  end
+
+  def test_delete_all_with_includes
+    pets = Pet.includes(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.delete_all
+  end
+
+  unless current_adapter?(:OracleAdapter)
+    def test_delete_all_with_order_and_limit_deletes_subset_only
+      author = authors(:david)
+      limited_posts = Post.where(author: author).order(:id).limit(1)
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.delete_all
+      assert_raise(ActiveRecord::RecordNotFound) { posts(:welcome) }
+      assert posts(:thinking)
+    end
+
+    def test_delete_all_with_order_and_limit_and_offset_deletes_subset_only
+      author = authors(:david)
+      limited_posts = Post.where(author: author).order(:id).limit(1).offset(1)
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.delete_all
+      assert_raise(ActiveRecord::RecordNotFound) { posts(:thinking) }
+      assert posts(:welcome)
+    end
+  end
+end
diff --git a/activerecord/test/cases/relation/merging_test.rb b/activerecord/test/cases/relation/merging_test.rb
index f53ef1fe35..224e4f39a8 100644
--- a/activerecord/test/cases/relation/merging_test.rb
+++ b/activerecord/test/cases/relation/merging_test.rb
@@ -121,6 +121,20 @@ class RelationMergingTest < ActiveRecord::TestCase
     relation = relation.merge(Post.from("posts"))
     assert_not_empty relation.from_clause
   end
+
+  def test_merging_with_from_clause_on_different_class
+    assert Comment.joins(:post).merge(Post.from("posts")).first
+  end
+
+  def test_merging_with_order_with_binds
+    relation = Post.all.merge(Post.order([Arel.sql("title LIKE ?"), "%suffix"]))
+    assert_equal ["title LIKE '%suffix'"], relation.order_values
+  end
+
+  def test_merging_with_order_without_binds
+    relation = Post.all.merge(Post.order(Arel.sql("title LIKE '%?'")))
+    assert_equal ["title LIKE '%?'"], relation.order_values
+  end
 end
 
 class MergingDifferentRelationsTest < ActiveRecord::TestCase
diff --git a/activerecord/test/cases/relation/update_all_test.rb b/activerecord/test/cases/relation/update_all_test.rb
new file mode 100644
index 0000000000..09c365f31b
--- /dev/null
+++ b/activerecord/test/cases/relation/update_all_test.rb
@@ -0,0 +1,239 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+require "models/author"
+require "models/category"
+require "models/comment"
+require "models/computer"
+require "models/developer"
+require "models/post"
+require "models/person"
+require "models/pet"
+require "models/toy"
+require "models/topic"
+require "models/tag"
+require "models/tagging"
+require "models/warehouse_thing"
+
+class UpdateAllTest < ActiveRecord::TestCase
+  fixtures :authors, :author_addresses, :comments, :developers, :posts, :people, :pets, :toys, :tags, :taggings, "warehouse-things"
+
+  class TopicWithCallbacks < ActiveRecord::Base
+    self.table_name = :topics
+    cattr_accessor :topic_count
+    before_update { |topic| topic.author_name = "David" if topic.author_name.blank? }
+    after_update { |topic| topic.class.topic_count = topic.class.count }
+  end
+
+  def test_update_all_with_scope
+    tag = Tag.first
+    Post.tagged_with(tag.id).update_all(title: "rofl")
+    posts = Post.tagged_with(tag.id).all.to_a
+    assert_operator posts.length, :>, 0
+    posts.each { |post| assert_equal "rofl", post.title }
+  end
+
+  def test_update_all_with_non_standard_table_name
+    assert_equal 1, WarehouseThing.where(id: 1).update_all(["value = ?", 0])
+    assert_equal 0, WarehouseThing.find(1).value
+  end
+
+  def test_update_all_with_blank_argument
+    assert_raises(ArgumentError) { Comment.update_all({}) }
+  end
+
+  def test_update_all_with_joins
+    pets = Pet.joins(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.update_all(name: "Bob")
+  end
+
+  def test_update_all_with_left_joins
+    pets = Pet.left_joins(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.update_all(name: "Bob")
+  end
+
+  def test_update_all_with_includes
+    pets = Pet.includes(:toys).where(toys: { name: "Bone" })
+
+    assert_equal true, pets.exists?
+    assert_equal pets.count, pets.update_all(name: "Bob")
+  end
+
+  def test_update_all_with_joins_and_limit
+    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).limit(1)
+    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+  end
+
+  def test_update_all_with_joins_and_limit_and_order
+    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("comments.id").limit(1)
+    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:greetings).post
+    assert_equal posts(:welcome),  comments(:more_greetings).post
+  end
+
+  def test_update_all_with_joins_and_offset
+    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id)
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
+  end
+
+  def test_update_all_with_joins_and_offset_and_order
+    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("posts.id", "comments.id")
+    count        = all_comments.count
+    comments     = all_comments.offset(1)
+
+    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
+    assert_equal posts(:thinking), comments(:more_greetings).post
+    assert_equal posts(:welcome),  comments(:greetings).post
+  end
+
+  def test_update_counters_with_joins
+    assert_nil pets(:parrot).integer
+
+    Pet.joins(:toys).where(toys: { name: "Bone" }).update_counters(integer: 1)
+
+    assert_equal 1, pets(:parrot).reload.integer
+  end
+
+  def test_touch_all_updates_records_timestamps
+    david = developers(:david)
+    david_previously_updated_at = david.updated_at
+    jamis = developers(:jamis)
+    jamis_previously_updated_at = jamis.updated_at
+    Developer.where(name: "David").touch_all
+
+    assert_not_equal david_previously_updated_at, david.reload.updated_at
+    assert_equal jamis_previously_updated_at, jamis.reload.updated_at
+  end
+
+  def test_touch_all_with_custom_timestamp
+    developer = developers(:david)
+    previously_created_at = developer.created_at
+    previously_updated_at = developer.updated_at
+    Developer.where(name: "David").touch_all(:created_at)
+    developer.reload
+
+    assert_not_equal previously_created_at, developer.created_at
+    assert_not_equal previously_updated_at, developer.updated_at
+  end
+
+  def test_touch_all_with_given_time
+    developer = developers(:david)
+    previously_created_at = developer.created_at
+    previously_updated_at = developer.updated_at
+    new_time = Time.utc(2015, 2, 16, 4, 54, 0)
+    Developer.where(name: "David").touch_all(:created_at, time: new_time)
+    developer.reload
+
+    assert_not_equal previously_created_at, developer.created_at
+    assert_not_equal previously_updated_at, developer.updated_at
+    assert_equal new_time, developer.created_at
+    assert_equal new_time, developer.updated_at
+  end
+
+  def test_touch_all_updates_locking_column
+    person = people(:david)
+
+    assert_difference -> { person.reload.lock_version }, +1 do
+      Person.where(first_name: "David").touch_all
+    end
+  end
+
+  def test_update_on_relation
+    topic1 = TopicWithCallbacks.create! title: "arel", author_name: nil
+    topic2 = TopicWithCallbacks.create! title: "activerecord", author_name: nil
+    topics = TopicWithCallbacks.where(id: [topic1.id, topic2.id])
+    topics.update(title: "adequaterecord")
+
+    assert_equal TopicWithCallbacks.count, TopicWithCallbacks.topic_count
+
+    assert_equal "adequaterecord", topic1.reload.title
+    assert_equal "adequaterecord", topic2.reload.title
+    # Testing that the before_update callbacks have run
+    assert_equal "David", topic1.reload.author_name
+    assert_equal "David", topic2.reload.author_name
+  end
+
+  def test_update_with_ids_on_relation
+    topic1 = TopicWithCallbacks.create!(title: "arel", author_name: nil)
+    topic2 = TopicWithCallbacks.create!(title: "activerecord", author_name: nil)
+    topics = TopicWithCallbacks.none
+    topics.update(
+      [topic1.id, topic2.id],
+      [{ title: "adequaterecord" }, { title: "adequaterecord" }]
+    )
+
+    assert_equal TopicWithCallbacks.count, TopicWithCallbacks.topic_count
+
+    assert_equal "adequaterecord", topic1.reload.title
+    assert_equal "adequaterecord", topic2.reload.title
+    # Testing that the before_update callbacks have run
+    assert_equal "David", topic1.reload.author_name
+    assert_equal "David", topic2.reload.author_name
+  end
+
+  def test_update_on_relation_passing_active_record_object_is_not_permitted
+    topic = Topic.create!(title: "Foo", author_name: nil)
+    assert_raises(ArgumentError) do
+      Topic.where(id: topic.id).update(topic, title: "Bar")
+    end
+  end
+
+  # Oracle UPDATE does not support ORDER BY
+  unless current_adapter?(:OracleAdapter)
+    def test_update_all_ignores_order_without_limit_from_association
+      author = authors(:david)
+      assert_nothing_raised do
+        assert_equal author.posts_with_comments_and_categories.length, author.posts_with_comments_and_categories.update_all([ "body = ?", "bulk update!" ])
+      end
+    end
+
+    def test_update_all_doesnt_ignore_order
+      assert_equal authors(:david).id + 1, authors(:mary).id # make sure there is going to be a duplicate PK error
+      test_update_with_order_succeeds = lambda do |order|
+        begin
+          Author.order(order).update_all("id = id + 1")
+        rescue ActiveRecord::ActiveRecordError
+          false
+        end
+      end
+
+      if test_update_with_order_succeeds.call("id DESC")
+        # test that this wasn't a fluke and using an incorrect order results in an exception
+        assert_not test_update_with_order_succeeds.call("id ASC")
+      else
+        # test that we're failing because the current Arel's engine doesn't support UPDATE ORDER BY queries is using subselects instead
+        assert_sql(/\AUPDATE .+ \(SELECT .* ORDER BY id DESC\)\z/i) do
+          test_update_with_order_succeeds.call("id DESC")
+        end
+      end
+    end
+
+    def test_update_all_with_order_and_limit_updates_subset_only
+      author = authors(:david)
+      limited_posts = author.posts_sorted_by_id_limited
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.update_all([ "body = ?", "bulk update!" ])
+      assert_equal "bulk update!", posts(:welcome).body
+      assert_not_equal "bulk update!", posts(:thinking).body
+    end
+
+    def test_update_all_with_order_and_limit_and_offset_updates_subset_only
+      author = authors(:david)
+      limited_posts = author.posts_sorted_by_id_limited.offset(1)
+      assert_equal 1, limited_posts.size
+      assert_equal 2, limited_posts.limit(2).size
+      assert_equal 1, limited_posts.update_all([ "body = ?", "bulk update!" ])
+      assert_equal "bulk update!", posts(:thinking).body
+      assert_not_equal "bulk update!", posts(:welcome).body
+    end
+  end
+end
diff --git a/activerecord/test/cases/relations_test.rb b/activerecord/test/cases/relations_test.rb
index 5412ab5def..9914a61033 100644
--- a/activerecord/test/cases/relations_test.rb
+++ b/activerecord/test/cases/relations_test.rb
@@ -9,6 +9,7 @@ require "models/comment"
 require "models/author"
 require "models/entrant"
 require "models/developer"
+require "models/project"
 require "models/person"
 require "models/computer"
 require "models/reply"
@@ -28,13 +29,6 @@ require "models/subscriber"
 class RelationTest < ActiveRecord::TestCase
   fixtures :authors, :author_addresses, :topics, :entrants, :developers, :people, :companies, :developers_projects, :accounts, :categories, :categorizations, :categories_posts, :posts, :comments, :tags, :taggings, :cars, :minivans
 
-  class TopicWithCallbacks < ActiveRecord::Base
-    self.table_name = :topics
-    cattr_accessor :topic_count
-    before_update { |topic| topic.author_name = "David" if topic.author_name.blank? }
-    after_update { |topic| topic.class.topic_count = topic.class.count }
-  end
-
   def test_do_not_double_quote_string_id
     van = Minivan.last
     assert van
@@ -862,45 +856,6 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal authors(:bob), authors.last
   end
 
-  def test_destroy_all
-    davids = Author.where(name: "David")
-
-    # Force load
-    assert_equal [authors(:david)], davids.to_a
-    assert_predicate davids, :loaded?
-
-    assert_difference("Author.count", -1) { davids.destroy_all }
-
-    assert_equal [], davids.to_a
-    assert_predicate davids, :loaded?
-  end
-
-  def test_delete_all
-    davids = Author.where(name: "David")
-
-    assert_difference("Author.count", -1) { davids.delete_all }
-    assert_not_predicate davids, :loaded?
-  end
-
-  def test_delete_all_loaded
-    davids = Author.where(name: "David")
-
-    # Force load
-    assert_equal [authors(:david)], davids.to_a
-    assert_predicate davids, :loaded?
-
-    assert_difference("Author.count", -1) { davids.delete_all }
-
-    assert_equal [], davids.to_a
-    assert_predicate davids, :loaded?
-  end
-
-  def test_delete_all_with_unpermitted_relation_raises_error
-    assert_raises(ActiveRecord::ActiveRecordError) { Author.distinct.delete_all }
-    assert_raises(ActiveRecord::ActiveRecordError) { Author.group(:name).delete_all }
-    assert_raises(ActiveRecord::ActiveRecordError) { Author.having("SUM(id) < 3").delete_all }
-  end
-
   def test_select_with_aggregates
     posts = Post.select(:title, :body)
 
@@ -985,14 +940,6 @@ class RelationTest < ActiveRecord::TestCase
     assert_queries(1) { assert_equal 11, posts.load.size }
   end
 
-  def test_update_all_with_scope
-    tag = Tag.first
-    Post.tagged_with(tag.id).update_all title: "rofl"
-    list = Post.tagged_with(tag.id).all.to_a
-    assert_operator list.length, :>, 0
-    list.each { |post| assert_equal "rofl", post.title }
-  end
-
   def test_count_explicit_columns
     Post.update_all(comments_count: nil)
     posts = Post.all
@@ -1405,6 +1352,16 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal "cock", hens.new.name
   end
 
+  def test_create_with_nested_attributes
+    assert_difference("Project.count", 1) do
+      developers = Developer.where(name: "Aaron")
+      developers = developers.create_with(
+        projects_attributes: [{ name: "p1" }]
+      )
+      developers.create!
+    end
+  end
+
   def test_except
     relation = Post.where(author_id: 1).order("id ASC").limit(1)
     assert_equal [posts(:welcome)], relation.to_a
@@ -1486,114 +1443,6 @@ class RelationTest < ActiveRecord::TestCase
     assert_equal authors(:david), Author.order("id DESC , name DESC").last
   end
 
-  def test_update_all_with_blank_argument
-    assert_raises(ArgumentError) { Comment.update_all({}) }
-  end
-
-  def test_update_all_with_joins
-    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id)
-    count    = comments.count
-
-    assert_equal count, comments.update_all(post_id: posts(:thinking).id)
-    assert_equal posts(:thinking), comments(:greetings).post
-  end
-
-  def test_update_all_with_joins_and_limit
-    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).limit(1)
-    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
-  end
-
-  def test_update_all_with_joins_and_limit_and_order
-    comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("comments.id").limit(1)
-    assert_equal 1, comments.update_all(post_id: posts(:thinking).id)
-    assert_equal posts(:thinking), comments(:greetings).post
-    assert_equal posts(:welcome),  comments(:more_greetings).post
-  end
-
-  def test_update_all_with_joins_and_offset
-    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id)
-    count        = all_comments.count
-    comments     = all_comments.offset(1)
-
-    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
-  end
-
-  def test_update_all_with_joins_and_offset_and_order
-    all_comments = Comment.joins(:post).where("posts.id" => posts(:welcome).id).order("posts.id", "comments.id")
-    count        = all_comments.count
-    comments     = all_comments.offset(1)
-
-    assert_equal count - 1, comments.update_all(post_id: posts(:thinking).id)
-    assert_equal posts(:thinking), comments(:more_greetings).post
-    assert_equal posts(:welcome),  comments(:greetings).post
-  end
-
-  def test_touch_all_updates_records_timestamps
-    david = developers(:david)
-    david_previously_updated_at = david.updated_at
-    jamis = developers(:jamis)
-    jamis_previously_updated_at = jamis.updated_at
-    Developer.where(name: "David").touch_all
-
-    assert_not_equal david_previously_updated_at, david.reload.updated_at
-    assert_equal jamis_previously_updated_at, jamis.reload.updated_at
-  end
-
-  def test_touch_all_with_custom_timestamp
-    developer = developers(:david)
-    previously_created_at = developer.created_at
-    previously_updated_at = developer.updated_at
-    Developer.where(name: "David").touch_all(:created_at)
-    developer = developer.reload
-
-    assert_not_equal previously_created_at, developer.created_at
-    assert_not_equal previously_updated_at, developer.updated_at
-  end
-
-  def test_touch_all_with_given_time
-    developer = developers(:david)
-    previously_created_at = developer.created_at
-    previously_updated_at = developer.updated_at
-    new_time = Time.utc(2015, 2, 16, 4, 54, 0)
-    Developer.where(name: "David").touch_all(:created_at, time: new_time)
-    developer = developer.reload
-
-    assert_not_equal previously_created_at, developer.created_at
-    assert_not_equal previously_updated_at, developer.updated_at
-    assert_equal new_time, developer.created_at
-    assert_equal new_time, developer.updated_at
-  end
-
-  def test_touch_all_updates_locking_column
-    person = people(:david)
-
-    assert_difference -> { person.reload.lock_version }, +1 do
-      Person.where(first_name: "David").touch_all
-    end
-  end
-
-  def test_update_on_relation
-    topic1 = TopicWithCallbacks.create! title: "arel", author_name: nil
-    topic2 = TopicWithCallbacks.create! title: "activerecord", author_name: nil
-    topics = TopicWithCallbacks.where(id: [topic1.id, topic2.id])
-    topics.update(title: "adequaterecord")
-
-    assert_equal TopicWithCallbacks.count, TopicWithCallbacks.topic_count
-
-    assert_equal "adequaterecord", topic1.reload.title
-    assert_equal "adequaterecord", topic2.reload.title
-    # Testing that the before_update callbacks have run
-    assert_equal "David", topic1.reload.author_name
-    assert_equal "David", topic2.reload.author_name
-  end
-
-  def test_update_on_relation_passing_active_record_object_is_not_permitted
-    topic = Topic.create!(title: "Foo", author_name: nil)
-    assert_raises(ArgumentError) do
-      Topic.where(id: topic.id).update(topic, title: "Bar")
-    end
-  end
-
   def test_distinct
     tag1 = Tag.create(name: "Foo")
     tag2 = Tag.create(name: "Foo")
diff --git a/activerecord/test/cases/result_test.rb b/activerecord/test/cases/result_test.rb
index 68fcafb682..825aee2423 100644
--- a/activerecord/test/cases/result_test.rb
+++ b/activerecord/test/cases/result_test.rb
@@ -21,12 +21,22 @@ module ActiveRecord
       assert_equal 3, result.length
     end
 
-    test "to_hash returns row_hashes" do
+    test "to_a returns row_hashes" do
       assert_equal [
         { "col_1" => "row 1 col 1", "col_2" => "row 1 col 2" },
         { "col_1" => "row 2 col 1", "col_2" => "row 2 col 2" },
         { "col_1" => "row 3 col 1", "col_2" => "row 3 col 2" },
-      ], result.to_hash
+      ], result.to_a
+    end
+
+    test "to_hash (deprecated) returns row_hashes" do
+      assert_deprecated do
+        assert_equal [
+          { "col_1" => "row 1 col 1", "col_2" => "row 1 col 2" },
+          { "col_1" => "row 2 col 1", "col_2" => "row 2 col 2" },
+          { "col_1" => "row 3 col 1", "col_2" => "row 3 col 2" },
+        ], result.to_hash
+      end
     end
 
     test "first returns first row as a hash" do
diff --git a/activerecord/test/cases/schema_dumper_test.rb b/activerecord/test/cases/schema_dumper_test.rb
index 75b68b521c..db13f20a39 100644
--- a/activerecord/test/cases/schema_dumper_test.rb
+++ b/activerecord/test/cases/schema_dumper_test.rb
@@ -226,6 +226,20 @@ class SchemaDumperTest < ActiveRecord::TestCase
     assert_match %r{t\.float\s+"temperature"$}, output
   end
 
+  if ActiveRecord::Base.connection.supports_expression_index?
+    def test_schema_dump_expression_indices
+      index_definition = dump_table_schema("companies").split(/\n/).grep(/t\.index.*company_expression_index/).first.strip
+
+      if current_adapter?(:PostgreSQLAdapter)
+        assert_match %r{CASE.+lower\(\(name\)::text\)}i, index_definition
+      elsif current_adapter?(:SQLite3Adapter)
+        assert_match %r{CASE.+lower\(name\)}i, index_definition
+      else
+        assert false
+      end
+    end
+  end
+
   if current_adapter?(:Mysql2Adapter)
     def test_schema_dump_includes_length_for_mysql_binary_fields
       output = standard_dump
@@ -278,11 +292,6 @@ class SchemaDumperTest < ActiveRecord::TestCase
       assert_match %r{t\.decimal\s+"decimal_array_default",\s+default: \["1.23", "3.45"\],\s+array: true}, output
     end
 
-    def test_schema_dump_expression_indices
-      index_definition = dump_table_schema("companies").split(/\n/).grep(/t\.index.*company_expression_index/).first.strip
-      assert_match %r{CASE.+lower\(\(name\)::text\)}i, index_definition
-    end
-
     def test_schema_dump_interval_type
       output = dump_table_schema "postgresql_times"
       assert_match %r{t\.interval\s+"time_interval"$}, output
diff --git a/activerecord/test/cases/scoping/default_scoping_test.rb b/activerecord/test/cases/scoping/default_scoping_test.rb
index e3a34aa50d..6281712df6 100644
--- a/activerecord/test/cases/scoping/default_scoping_test.rb
+++ b/activerecord/test/cases/scoping/default_scoping_test.rb
@@ -4,6 +4,7 @@ require "cases/helper"
 require "models/post"
 require "models/comment"
 require "models/developer"
+require "models/project"
 require "models/computer"
 require "models/vehicle"
 require "models/cat"
@@ -366,6 +367,21 @@ class DefaultScopingTest < ActiveRecord::TestCase
     assert_equal "Jamis", jamis.name
   end
 
+  def test_create_with_takes_precedence_over_where
+    developer = Developer.where(name: nil).create_with(name: "Aaron").new
+    assert_equal "Aaron", developer.name
+  end
+
+  def test_create_with_nested_attributes
+    assert_difference("Project.count", 1) do
+      Developer.create_with(
+        projects_attributes: [{ name: "p1" }]
+      ).scoping do
+        Developer.create!(name: "Aaron")
+      end
+    end
+  end
+
   # FIXME: I don't know if this is *desired* behavior, but it is *today's*
   # behavior.
   def test_create_with_empty_hash_will_not_reset
diff --git a/activerecord/test/cases/scoping/named_scoping_test.rb b/activerecord/test/cases/scoping/named_scoping_test.rb
index 4214f347fb..f707951a16 100644
--- a/activerecord/test/cases/scoping/named_scoping_test.rb
+++ b/activerecord/test/cases/scoping/named_scoping_test.rb
@@ -489,7 +489,7 @@ class NamedScopingTest < ActiveRecord::TestCase
     [:public_method, :protected_method, :private_method].each do |reserved_method|
       assert Topic.respond_to?(reserved_method, true)
       assert_called(ActiveRecord::Base.logger, :warn) do
-        silence_warnings { Topic.scope(reserved_method, -> {}) }
+        silence_warnings { Topic.scope(reserved_method, -> { }) }
       end
     end
   end
diff --git a/activerecord/test/cases/scoping/relation_scoping_test.rb b/activerecord/test/cases/scoping/relation_scoping_test.rb
index 544adc9b39..b4f4379e5e 100644
--- a/activerecord/test/cases/scoping/relation_scoping_test.rb
+++ b/activerecord/test/cases/scoping/relation_scoping_test.rb
@@ -236,8 +236,8 @@ class RelationScopingTest < ActiveRecord::TestCase
       SpecialComment.unscoped.created
     end
 
-    assert_nil Comment.current_scope
-    assert_nil SpecialComment.current_scope
+    assert_nil Comment.send(:current_scope)
+    assert_nil SpecialComment.send(:current_scope)
   end
 
   def test_scoping_respects_current_class
diff --git a/activerecord/test/cases/serialized_attribute_test.rb b/activerecord/test/cases/serialized_attribute_test.rb
index 4cd4515c3b..1192b30b14 100644
--- a/activerecord/test/cases/serialized_attribute_test.rb
+++ b/activerecord/test/cases/serialized_attribute_test.rb
@@ -322,7 +322,7 @@ class SerializedAttributeTest < ActiveRecord::TestCase
     topic = Topic.create!(content: {})
     topic2 = Topic.create!(content: nil)
 
-    assert_equal [topic, topic2], Topic.where(content: nil)
+    assert_equal [topic, topic2], Topic.where(content: nil).sort_by(&:id)
   end
 
   def test_nil_is_always_persisted_as_null
diff --git a/activerecord/test/cases/suppressor_test.rb b/activerecord/test/cases/suppressor_test.rb
index b68f0033d9..9be5356901 100644
--- a/activerecord/test/cases/suppressor_test.rb
+++ b/activerecord/test/cases/suppressor_test.rb
@@ -66,7 +66,7 @@ class SuppressorTest < ActiveRecord::TestCase
   def test_suppresses_when_nested_multiple_times
     assert_no_difference -> { Notification.count } do
       Notification.suppress do
-        Notification.suppress {}
+        Notification.suppress { }
         Notification.create
         Notification.create!
         Notification.new.save
diff --git a/activerecord/test/cases/tasks/database_tasks_test.rb b/activerecord/test/cases/tasks/database_tasks_test.rb
index a6efe3fa5e..d674bd562f 100644
--- a/activerecord/test/cases/tasks/database_tasks_test.rb
+++ b/activerecord/test/cases/tasks/database_tasks_test.rb
@@ -46,35 +46,46 @@ module ActiveRecord
 
   class DatabaseTasksUtilsTask < ActiveRecord::TestCase
     def test_raises_an_error_when_called_with_protected_environment
-      ActiveRecord::MigrationContext.any_instance.stubs(:current_version).returns(1)
-
       protected_environments = ActiveRecord::Base.protected_environments
       current_env            = ActiveRecord::Base.connection.migration_context.current_environment
-      assert_not_includes protected_environments, current_env
-      # Assert no error
-      ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
-
-      ActiveRecord::Base.protected_environments = [current_env]
 
-      assert_raise(ActiveRecord::ProtectedEnvironmentError) do
+      assert_called_on_instance_of(
+        ActiveRecord::MigrationContext,
+        :current_version,
+        times: 6,
+        returns: 1
+      ) do
+        assert_not_includes protected_environments, current_env
+        # Assert no error
         ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+
+        ActiveRecord::Base.protected_environments = [current_env]
+
+        assert_raise(ActiveRecord::ProtectedEnvironmentError) do
+          ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+        end
       end
     ensure
       ActiveRecord::Base.protected_environments = protected_environments
     end
 
     def test_raises_an_error_when_called_with_protected_environment_which_name_is_a_symbol
-      ActiveRecord::MigrationContext.any_instance.stubs(:current_version).returns(1)
-
       protected_environments = ActiveRecord::Base.protected_environments
       current_env            = ActiveRecord::Base.connection.migration_context.current_environment
-      assert_not_includes protected_environments, current_env
-      # Assert no error
-      ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
-
-      ActiveRecord::Base.protected_environments = [current_env.to_sym]
-      assert_raise(ActiveRecord::ProtectedEnvironmentError) do
+      assert_called_on_instance_of(
+        ActiveRecord::MigrationContext,
+        :current_version,
+        times: 6,
+        returns: 1
+      ) do
+        assert_not_includes protected_environments, current_env
+        # Assert no error
         ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+
+        ActiveRecord::Base.protected_environments = [current_env.to_sym]
+        assert_raise(ActiveRecord::ProtectedEnvironmentError) do
+          ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+        end
       end
     ensure
       ActiveRecord::Base.protected_environments = protected_environments
@@ -82,10 +93,14 @@ module ActiveRecord
 
     def test_raises_an_error_if_no_migrations_have_been_made
       ActiveRecord::InternalMetadata.stub(:table_exists?, false) do
-        ActiveRecord::MigrationContext.any_instance.stubs(:current_version).returns(1)
-
-        assert_raise(ActiveRecord::NoEnvironmentInSchemaError) do
-          ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+        assert_called_on_instance_of(
+          ActiveRecord::MigrationContext,
+          :current_version,
+          returns: 1
+        ) do
+          assert_raise(ActiveRecord::NoEnvironmentInSchemaError) do
+            ActiveRecord::Tasks::DatabaseTasks.check_protected_environments!
+          end
         end
       end
     end
@@ -213,18 +228,17 @@ module ActiveRecord
     end
 
     private
-
       def with_stubbed_configurations_establish_connection
-        ActiveRecord::Base.stub(:configurations, @configurations) do
-          # To refrain from connecting to a newly created empty DB in
-          # sqlite3_mem tests
-          ActiveRecord::Base.connection_handler.stub(
-            :establish_connection,
-            nil
-          ) do
-            yield
-          end
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        # To refrain from connecting to a newly created empty DB in
+        # sqlite3_mem tests
+        ActiveRecord::Base.connection_handler.stub(:establish_connection, nil) do
+          yield
         end
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
       end
   end
 
@@ -233,7 +247,7 @@ module ActiveRecord
       @configurations = {
         "development" => { "database" => "dev-db" },
         "test"        => { "database" => "test-db" },
-        "production"  => { "url" => "prod-db-url" }
+        "production"  => { "url" => "abstract://prod-db-host/prod-db" }
       }
     end
 
@@ -256,7 +270,7 @@ module ActiveRecord
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :create,
-          ["url" => "prod-db-url"],
+          ["adapter" => "abstract", "database" => "prod-db", "host" => "prod-db-host"],
         ) do
           ActiveRecord::Tasks::DatabaseTasks.create_current(
             ActiveSupport::StringInquirer.new("production")
@@ -315,13 +329,15 @@ module ActiveRecord
     end
 
     private
-
       def with_stubbed_configurations_establish_connection
-        ActiveRecord::Base.stub(:configurations, @configurations) do
-          ActiveRecord::Base.stub(:establish_connection, nil) do
-            yield
-          end
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        ActiveRecord::Base.connection_handler.stub(:establish_connection, nil) do
+          yield
         end
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
       end
   end
 
@@ -330,7 +346,7 @@ module ActiveRecord
       @configurations = {
         "development" => { "primary" => { "database" => "dev-db" }, "secondary" => { "database" => "secondary-dev-db" } },
         "test" => { "primary" => { "database" => "test-db" }, "secondary" => { "database" => "secondary-test-db" } },
-        "production" => { "primary" => { "url" => "prod-db-url" }, "secondary" => { "url" => "secondary-prod-db-url" } }
+        "production" => { "primary" => { "url" => "abstract://prod-db-host/prod-db" }, "secondary" => { "url" => "abstract://secondary-prod-db-host/secondary-prod-db" } }
       }
     end
 
@@ -357,8 +373,8 @@ module ActiveRecord
           ActiveRecord::Tasks::DatabaseTasks,
           :create,
           [
-            ["url" => "prod-db-url"],
-            ["url" => "secondary-prod-db-url"]
+            ["adapter" => "abstract", "database" => "prod-db", "host" => "prod-db-host"],
+            ["adapter" => "abstract", "database" => "secondary-prod-db", "host" => "secondary-prod-db-host"]
           ]
         ) do
           ActiveRecord::Tasks::DatabaseTasks.create_current(
@@ -426,13 +442,15 @@ module ActiveRecord
     end
 
     private
-
       def with_stubbed_configurations_establish_connection
-        ActiveRecord::Base.stub(:configurations, @configurations) do
-          ActiveRecord::Base.stub(:establish_connection, nil) do
-            yield
-          end
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        ActiveRecord::Base.connection_handler.stub(:establish_connection, nil) do
+          yield
         end
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
       end
   end
 
@@ -465,7 +483,7 @@ module ActiveRecord
     def test_ignores_configurations_without_databases
       @configurations[:development]["database"] = nil
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_not_called(ActiveRecord::Tasks::DatabaseTasks, :drop) do
           ActiveRecord::Tasks::DatabaseTasks.drop_all
         end
@@ -475,7 +493,7 @@ module ActiveRecord
     def test_ignores_remote_databases
       @configurations[:development]["host"] = "my.server.tld"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_not_called(ActiveRecord::Tasks::DatabaseTasks, :drop) do
           ActiveRecord::Tasks::DatabaseTasks.drop_all
         end
@@ -485,7 +503,7 @@ module ActiveRecord
     def test_warning_for_remote_databases
       @configurations[:development]["host"] = "my.server.tld"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         ActiveRecord::Tasks::DatabaseTasks.drop_all
 
         assert_match "This task only modifies local databases. my-db is on a remote host.",
@@ -496,7 +514,7 @@ module ActiveRecord
     def test_drops_configurations_with_local_ip
       @configurations[:development]["host"] = "127.0.0.1"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called(ActiveRecord::Tasks::DatabaseTasks, :drop) do
           ActiveRecord::Tasks::DatabaseTasks.drop_all
         end
@@ -506,7 +524,7 @@ module ActiveRecord
     def test_drops_configurations_with_local_host
       @configurations[:development]["host"] = "localhost"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called(ActiveRecord::Tasks::DatabaseTasks, :drop) do
           ActiveRecord::Tasks::DatabaseTasks.drop_all
         end
@@ -516,12 +534,22 @@ module ActiveRecord
     def test_drops_configurations_with_blank_hosts
       @configurations[:development]["host"] = nil
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called(ActiveRecord::Tasks::DatabaseTasks, :drop) do
           ActiveRecord::Tasks::DatabaseTasks.drop_all
         end
       end
     end
+
+    private
+      def with_stubbed_configurations
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        yield
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
+      end
   end
 
   class DatabaseTasksDropCurrentTest < ActiveRecord::TestCase
@@ -529,12 +557,12 @@ module ActiveRecord
       @configurations = {
         "development" => { "database" => "dev-db" },
         "test"        => { "database" => "test-db" },
-        "production"  => { "url" => "prod-db-url" }
+        "production"  => { "url" => "abstract://prod-db-host/prod-db" }
       }
     end
 
     def test_drops_current_environment_database
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(ActiveRecord::Tasks::DatabaseTasks, :drop,
           ["database" => "test-db"]) do
           ActiveRecord::Tasks::DatabaseTasks.drop_current(
@@ -545,9 +573,9 @@ module ActiveRecord
     end
 
     def test_drops_current_environment_database_with_url
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(ActiveRecord::Tasks::DatabaseTasks, :drop,
-          ["url" => "prod-db-url"]) do
+          ["adapter" => "abstract", "database" => "prod-db", "host" => "prod-db-host"]) do
           ActiveRecord::Tasks::DatabaseTasks.drop_current(
             ActiveSupport::StringInquirer.new("production")
           )
@@ -556,7 +584,7 @@ module ActiveRecord
     end
 
     def test_drops_test_and_development_databases_when_env_was_not_specified
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
@@ -576,7 +604,7 @@ module ActiveRecord
       old_env = ENV["RAILS_ENV"]
       ENV["RAILS_ENV"] = "development"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
@@ -593,6 +621,16 @@ module ActiveRecord
     ensure
       ENV["RAILS_ENV"] = old_env
     end
+
+    private
+      def with_stubbed_configurations
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        yield
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
+      end
   end
 
   class DatabaseTasksDropCurrentThreeTierTest < ActiveRecord::TestCase
@@ -600,12 +638,12 @@ module ActiveRecord
       @configurations = {
         "development" => { "primary" => { "database" => "dev-db" }, "secondary" => { "database" => "secondary-dev-db" } },
         "test" => { "primary" => { "database" => "test-db" }, "secondary" => { "database" => "secondary-test-db" } },
-        "production" => { "primary" => { "url" => "prod-db-url" }, "secondary" => { "url" => "secondary-prod-db-url" } }
+        "production" => { "primary" => { "url" => "abstract://prod-db-host/prod-db" }, "secondary" => { "url" => "abstract://secondary-prod-db-host/secondary-prod-db" } }
       }
     end
 
     def test_drops_current_environment_database
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
@@ -622,13 +660,13 @@ module ActiveRecord
     end
 
     def test_drops_current_environment_database_with_url
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
           [
-            ["url" => "prod-db-url"],
-            ["url" => "secondary-prod-db-url"]
+            ["adapter" => "abstract", "database" => "prod-db", "host" => "prod-db-host"],
+            ["adapter" => "abstract", "database" => "secondary-prod-db", "host" => "secondary-prod-db-host"]
           ]
         ) do
           ActiveRecord::Tasks::DatabaseTasks.drop_current(
@@ -639,7 +677,7 @@ module ActiveRecord
     end
 
     def test_drops_test_and_development_databases_when_env_was_not_specified
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
@@ -661,7 +699,7 @@ module ActiveRecord
       old_env = ENV["RAILS_ENV"]
       ENV["RAILS_ENV"] = "development"
 
-      ActiveRecord::Base.stub(:configurations, @configurations) do
+      with_stubbed_configurations do
         assert_called_with(
           ActiveRecord::Tasks::DatabaseTasks,
           :drop,
@@ -680,6 +718,16 @@ module ActiveRecord
     ensure
       ENV["RAILS_ENV"] = old_env
     end
+
+    private
+      def with_stubbed_configurations
+        old_configurations = ActiveRecord::Base.configurations
+        ActiveRecord::Base.configurations = @configurations
+
+        yield
+      ensure
+        ActiveRecord::Base.configurations = old_configurations
+      end
   end
 
   if current_adapter?(:SQLite3Adapter) && !in_memory_db?
@@ -833,37 +881,44 @@ module ActiveRecord
 
   class DatabaseTasksPurgeCurrentTest < ActiveRecord::TestCase
     def test_purges_current_environment_database
+      old_configurations = ActiveRecord::Base.configurations
       configurations = {
         "development" => { "database" => "dev-db" },
         "test"        => { "database" => "test-db" },
         "production"  => { "database" => "prod-db" }
       }
-      ActiveRecord::Base.stub(:configurations, configurations) do
-        assert_called_with(
-          ActiveRecord::Tasks::DatabaseTasks,
-          :purge,
-          ["database" => "prod-db"]
-        ) do
-          assert_called_with(ActiveRecord::Base, :establish_connection, [:production]) do
-            ActiveRecord::Tasks::DatabaseTasks.purge_current("production")
-          end
+
+      ActiveRecord::Base.configurations = configurations
+
+      assert_called_with(
+        ActiveRecord::Tasks::DatabaseTasks,
+        :purge,
+        ["database" => "prod-db"]
+      ) do
+        assert_called_with(ActiveRecord::Base, :establish_connection, [:production]) do
+          ActiveRecord::Tasks::DatabaseTasks.purge_current("production")
         end
       end
+    ensure
+      ActiveRecord::Base.configurations = old_configurations
     end
   end
 
   class DatabaseTasksPurgeAllTest < ActiveRecord::TestCase
     def test_purge_all_local_configurations
+      old_configurations = ActiveRecord::Base.configurations
       configurations = { development: { "database" => "my-db" } }
-      ActiveRecord::Base.stub(:configurations, configurations) do
-        assert_called_with(
-          ActiveRecord::Tasks::DatabaseTasks,
-          :purge,
-          ["database" => "my-db"]
-        ) do
-          ActiveRecord::Tasks::DatabaseTasks.purge_all
-        end
+      ActiveRecord::Base.configurations = configurations
+
+      assert_called_with(
+        ActiveRecord::Tasks::DatabaseTasks,
+        :purge,
+        ["database" => "my-db"]
+      ) do
+        ActiveRecord::Tasks::DatabaseTasks.purge_all
       end
+    ensure
+      ActiveRecord::Base.configurations = old_configurations
     end
   end
 
diff --git a/activerecord/test/cases/tasks/mysql_rake_test.rb b/activerecord/test/cases/tasks/mysql_rake_test.rb
index eeb4222d97..4d6dff68f9 100644
--- a/activerecord/test/cases/tasks/mysql_rake_test.rb
+++ b/activerecord/test/cases/tasks/mysql_rake_test.rb
@@ -152,10 +152,14 @@ if current_adapter?(:Mysql2Adapter)
       end
 
       def test_establishes_connection_to_mysql_database
-        with_stubbed_connection_establish_connection do
-          ActiveRecord::Base.expects(:establish_connection).with @configuration
-
-          ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+        ActiveRecord::Base.stub(:connection, @connection) do
+          assert_called_with(
+            ActiveRecord::Base,
+            :establish_connection,
+            [@configuration]
+          ) do
+            ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+          end
         end
       end
 
@@ -196,10 +200,14 @@ if current_adapter?(:Mysql2Adapter)
       end
 
       def test_establishes_connection_to_the_appropriate_database
-        with_stubbed_connection_establish_connection do
-          ActiveRecord::Base.expects(:establish_connection).with(@configuration)
-
-          ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+        ActiveRecord::Base.stub(:connection, @connection) do
+          assert_called_with(
+            ActiveRecord::Base,
+            :establish_connection,
+            [@configuration]
+          ) do
+            ActiveRecord::Tasks::DatabaseTasks.purge @configuration
+          end
         end
       end
 
diff --git a/activerecord/test/cases/tasks/postgresql_rake_test.rb b/activerecord/test/cases/tasks/postgresql_rake_test.rb
index 00005e7a0d..065ba7734c 100644
--- a/activerecord/test/cases/tasks/postgresql_rake_test.rb
+++ b/activerecord/test/cases/tasks/postgresql_rake_test.rb
@@ -112,7 +112,7 @@ if current_adapter?(:PostgreSQLAdapter)
         ActiveRecord::Base.stub(:connection, @connection) do
           ActiveRecord::Base.stub(:establish_connection, -> * { raise Exception }) do
             assert_raises(Exception) { ActiveRecord::Tasks::DatabaseTasks.create @configuration }
-            assert_match "Couldn't create database for #{@configuration.inspect}", $stderr.string
+            assert_match "Couldn't create '#{@configuration['database']}' database. Please check your configuration.", $stderr.string
           end
         end
       end
@@ -166,12 +166,17 @@ if current_adapter?(:PostgreSQLAdapter)
 
       def test_establishes_connection_to_postgresql_database
         ActiveRecord::Base.stub(:connection, @connection) do
-          ActiveRecord::Base.expects(:establish_connection).with(
-            "adapter"            => "postgresql",
-            "database"           => "postgres",
-            "schema_search_path" => "public"
-          )
-          ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+          assert_called_with(
+            ActiveRecord::Base,
+            :establish_connection,
+            [
+              "adapter"            => "postgresql",
+              "database"           => "postgres",
+              "schema_search_path" => "public"
+            ]
+          ) do
+            ActiveRecord::Tasks::DatabaseTasks.drop @configuration
+          end
         end
       end
 
@@ -491,7 +496,7 @@ if current_adapter?(:PostgreSQLAdapter)
         assert_called_with(
           Kernel,
           :system,
-          ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, @configuration["database"]],
+          ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-X", "-f", filename, @configuration["database"]],
           returns: true
         ) do
           ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
@@ -500,7 +505,7 @@ if current_adapter?(:PostgreSQLAdapter)
 
       def test_structure_load_with_extra_flags
         filename = "awesome-file.sql"
-        expected_command = ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, "--noop", @configuration["database"]]
+        expected_command = ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-X", "-f", filename, "--noop", @configuration["database"]]
 
         assert_called_with(Kernel, :system, expected_command, returns: true) do
           with_structure_load_flags(["--noop"]) do
@@ -514,7 +519,7 @@ if current_adapter?(:PostgreSQLAdapter)
         assert_called_with(
           Kernel,
           :system,
-          ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-f", filename, @configuration["database"]],
+          ["psql", "-v", "ON_ERROR_STOP=1", "-q", "-X", "-f", filename, @configuration["database"]],
           returns: true
         ) do
           ActiveRecord::Tasks::DatabaseTasks.structure_load(@configuration, filename)
diff --git a/activerecord/test/cases/tasks/sqlite_rake_test.rb b/activerecord/test/cases/tasks/sqlite_rake_test.rb
index 7eb062b456..c1092b97c1 100644
--- a/activerecord/test/cases/tasks/sqlite_rake_test.rb
+++ b/activerecord/test/cases/tasks/sqlite_rake_test.rb
@@ -47,9 +47,9 @@ if current_adapter?(:SQLite3Adapter)
 
       def test_db_create_with_file_does_nothing
         File.stub(:exist?, true) do
-          ActiveRecord::Base.expects(:establish_connection).never
-
-          ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+          assert_not_called(ActiveRecord::Base, :establish_connection) do
+            ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root"
+          end
         end
       end
 
@@ -62,7 +62,7 @@ if current_adapter?(:SQLite3Adapter)
       def test_db_create_with_error_prints_message
         ActiveRecord::Base.stub(:establish_connection, proc { raise Exception }) do
           assert_raises(Exception) { ActiveRecord::Tasks::DatabaseTasks.create @configuration, "/rails/root" }
-          assert_match "Couldn't create database for #{@configuration.inspect}", $stderr.string
+          assert_match "Couldn't create '#{@configuration['database']}' database. Please check your configuration.", $stderr.string
         end
       end
     end
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
index 409b07e56c..40947767f3 100644
--- a/activerecord/test/cases/test_case.rb
+++ b/activerecord/test/cases/test_case.rb
@@ -31,6 +31,7 @@ module ActiveRecord
     end
 
     def capture_sql
+      ActiveRecord::Base.connection.materialize_transactions
       SQLCounter.clear_log
       yield
       SQLCounter.log_all.dup
@@ -48,6 +49,7 @@ module ActiveRecord
 
     def assert_queries(num = 1, options = {})
       ignore_none = options.fetch(:ignore_none) { num == :any }
+      ActiveRecord::Base.connection.materialize_transactions
       SQLCounter.clear_log
       x = yield
       the_log = ignore_none ? SQLCounter.log_all : SQLCounter.log
diff --git a/activerecord/test/cases/transaction_isolation_test.rb b/activerecord/test/cases/transaction_isolation_test.rb
index eaafd13360..2932969412 100644
--- a/activerecord/test/cases/transaction_isolation_test.rb
+++ b/activerecord/test/cases/transaction_isolation_test.rb
@@ -11,7 +11,7 @@ unless ActiveRecord::Base.connection.supports_transaction_isolation?
 
     test "setting the isolation level raises an error" do
       assert_raises(ActiveRecord::TransactionIsolationError) do
-        Tag.transaction(isolation: :serializable) {}
+        Tag.transaction(isolation: :serializable) { Tag.connection.materialize_transactions }
       end
     end
   end
@@ -90,7 +90,7 @@ else
     test "setting isolation when joining a transaction raises an error" do
       Tag.transaction do
         assert_raises(ActiveRecord::TransactionIsolationError) do
-          Tag.transaction(isolation: :serializable) {}
+          Tag.transaction(isolation: :serializable) { }
         end
       end
     end
@@ -98,7 +98,7 @@ else
     test "setting isolation when starting a nested transaction raises error" do
       Tag.transaction do
         assert_raises(ActiveRecord::TransactionIsolationError) do
-          Tag.transaction(requires_new: true, isolation: :serializable) {}
+          Tag.transaction(requires_new: true, isolation: :serializable) { }
         end
       end
     end
diff --git a/activerecord/test/cases/transactions_test.rb b/activerecord/test/cases/transactions_test.rb
index 46463ac414..50740054f7 100644
--- a/activerecord/test/cases/transactions_test.rb
+++ b/activerecord/test/cases/transactions_test.rb
@@ -575,7 +575,7 @@ class TransactionTest < ActiveRecord::TestCase
         assert_called(Topic.connection, :rollback_db_transaction) do
           e = assert_raise RuntimeError do
             Topic.transaction do
-              # do nothing
+              Topic.connection.materialize_transactions
             end
           end
           assert_equal "OH NOES", e.message
@@ -930,7 +930,7 @@ class TransactionTest < ActiveRecord::TestCase
 
     klass = Class.new(ActiveRecord::Base) do
       self.table_name = "transaction_without_primary_keys"
-      after_commit {} # necessary to trigger the has_transactional_callbacks branch
+      after_commit { } # necessary to trigger the has_transactional_callbacks branch
     end
 
     assert_no_difference(-> { klass.count }) do
@@ -943,6 +943,76 @@ class TransactionTest < ActiveRecord::TestCase
     connection.drop_table "transaction_without_primary_keys", if_exists: true
   end
 
+  def test_empty_transaction_is_not_materialized
+    assert_no_queries do
+      Topic.transaction { }
+    end
+  end
+
+  def test_unprepared_statement_materializes_transaction
+    assert_sql(/BEGIN/i, /COMMIT/i) do
+      Topic.transaction { Topic.where("1=1").first }
+    end
+  end
+
+  if ActiveRecord::Base.connection.prepared_statements
+    def test_prepared_statement_materializes_transaction
+      Topic.first
+
+      assert_sql(/BEGIN/i, /COMMIT/i) do
+        Topic.transaction { Topic.first }
+      end
+    end
+  end
+
+  def test_savepoint_does_not_materialize_transaction
+    assert_no_queries do
+      Topic.transaction do
+        Topic.transaction(requires_new: true) { }
+      end
+    end
+  end
+
+  def test_raising_does_not_materialize_transaction
+    assert_raise(RuntimeError) do
+      assert_no_queries do
+        Topic.transaction { raise }
+      end
+    end
+  end
+
+  def test_accessing_raw_connection_materializes_transaction
+    assert_sql(/BEGIN/i, /COMMIT/i) do
+      Topic.transaction { Topic.connection.raw_connection }
+    end
+  end
+
+  def test_accessing_raw_connection_disables_lazy_transactions
+    Topic.connection.raw_connection
+
+    assert_sql(/BEGIN/i, /COMMIT/i) do
+      Topic.transaction { }
+    end
+  end
+
+  def test_checking_in_connection_reenables_lazy_transactions
+    connection = Topic.connection_pool.checkout
+    connection.raw_connection
+    Topic.connection_pool.checkin connection
+
+    assert_no_queries do
+      connection.transaction { }
+    end
+  end
+
+  def test_transactions_can_be_manually_materialized
+    assert_sql(/BEGIN/i, /COMMIT/i) do
+      Topic.transaction do
+        Topic.connection.materialize_transactions
+      end
+    end
+  end
+
   private
 
     %w(validation save destroy).each do |filter|
diff --git a/activerecord/test/cases/type/type_map_test.rb b/activerecord/test/cases/type/type_map_test.rb
index f3699c11a2..1ce515a90c 100644
--- a/activerecord/test/cases/type/type_map_test.rb
+++ b/activerecord/test/cases/type/type_map_test.rb
@@ -32,7 +32,7 @@ module ActiveRecord
       end
 
       def test_fuzzy_lookup
-        string = String.new
+        string = +""
         mapping = TypeMap.new
 
         mapping.register_type(/varchar/i, string)
@@ -41,7 +41,7 @@ module ActiveRecord
       end
 
       def test_aliasing_types
-        string = String.new
+        string = +""
         mapping = TypeMap.new
 
         mapping.register_type(/string/i, string)
@@ -73,7 +73,7 @@ module ActiveRecord
       end
 
       def test_register_proc
-        string = String.new
+        string = +""
         binary = Binary.new
         mapping = TypeMap.new
 
diff --git a/activerecord/test/cases/validations_test.rb b/activerecord/test/cases/validations_test.rb
index a33877f43a..66763c727f 100644
--- a/activerecord/test/cases/validations_test.rb
+++ b/activerecord/test/cases/validations_test.rb
@@ -3,11 +3,11 @@
 require "cases/helper"
 require "models/topic"
 require "models/reply"
-require "models/person"
 require "models/developer"
 require "models/computer"
 require "models/parrot"
 require "models/company"
+require "models/price_estimate"
 
 class ValidationsTest < ActiveRecord::TestCase
   fixtures :topics, :developers
@@ -183,6 +183,22 @@ class ValidationsTest < ActiveRecord::TestCase
     assert_not_predicate klass.new(wibble: BigDecimal("97.179")), :valid?
   end
 
+  def test_numericality_validator_wont_be_affected_by_custom_getter
+    price_estimate = PriceEstimate.new(price: 50)
+
+    assert_equal "$50.00", price_estimate.price
+    assert_equal 50, price_estimate.price_before_type_cast
+    assert_equal 50, price_estimate.read_attribute(:price)
+
+    assert_predicate price_estimate, :price_came_from_user?
+    assert_predicate price_estimate, :valid?
+
+    price_estimate.save!
+
+    assert_not_predicate price_estimate, :price_came_from_user?
+    assert_predicate price_estimate, :valid?
+  end
+
   def test_acceptance_validator_doesnt_require_db_connection
     klass = Class.new(ActiveRecord::Base) do
       self.table_name = "posts"
diff --git a/activerecord/test/config.example.yml b/activerecord/test/config.example.yml
index 4bcb2aeea6..be337ddcd8 100644
--- a/activerecord/test/config.example.yml
+++ b/activerecord/test/config.example.yml
@@ -54,11 +54,11 @@ connections:
   mysql2:
     arunit:
       username: rails
-      encoding: utf8
-      collation: utf8_unicode_ci
+      encoding: utf8mb4
+      collation: utf8mb4_unicode_ci
     arunit2:
       username: rails
-      encoding: utf8
+      encoding: utf8mb4
 
   oracle:
      arunit:
diff --git a/activerecord/test/fixtures/citations.yml b/activerecord/test/fixtures/citations.yml
new file mode 100644
index 0000000000..d31cb8efa1
--- /dev/null
+++ b/activerecord/test/fixtures/citations.yml
@@ -0,0 +1,4 @@
+<% 65536.times do |i| %>
+fixture_no_<%= i %>:
+  id: <%= i %>
+<% end %>
diff --git a/activerecord/test/models/author.rb b/activerecord/test/models/author.rb
index 75932c7eb6..8b5a2fa0c8 100644
--- a/activerecord/test/models/author.rb
+++ b/activerecord/test/models/author.rb
@@ -81,7 +81,7 @@ class Author < ActiveRecord::Base
            after_add: [:log_after_adding,  Proc.new { |o, r| o.post_log << "after_adding_proc#{r.id || '<new>'}" }]
   has_many :unchangeable_posts, class_name: "Post", before_add: :raise_exception, after_add: :log_after_adding
 
-  has_many :categorizations, -> {}
+  has_many :categorizations, -> { }
   has_many :categories, through: :categorizations
   has_many :named_categories, through: :categorizations
 
diff --git a/activerecord/test/models/citation.rb b/activerecord/test/models/citation.rb
index 3d786f27eb..cee3d18173 100644
--- a/activerecord/test/models/citation.rb
+++ b/activerecord/test/models/citation.rb
@@ -2,4 +2,5 @@
 
 class Citation < ActiveRecord::Base
   belongs_to :reference_of, class_name: "Book", foreign_key: :book2_id
+  has_many :citations
 end
diff --git a/activerecord/test/models/company.rb b/activerecord/test/models/company.rb
index d4d5275b78..838f515aad 100644
--- a/activerecord/test/models/company.rb
+++ b/activerecord/test/models/company.rb
@@ -122,6 +122,12 @@ class RestrictedWithErrorFirm < Company
   has_many :companies, -> { order("id") }, foreign_key: "client_of", dependent: :restrict_with_error
 end
 
+class Agency < Firm
+  has_many :projects, foreign_key: :firm_id
+
+  accepts_nested_attributes_for :projects
+end
+
 class Client < Company
   belongs_to :firm, foreign_key: "client_of"
   belongs_to :firm_with_basic_id, class_name: "Firm", foreign_key: "firm_id"
@@ -204,4 +210,12 @@ end
 class VerySpecialClient < SpecialClient
 end
 
+class NewlyContractedCompany < Company
+  has_many :new_contracts, foreign_key: "company_id"
+
+  before_save do
+    self.new_contracts << NewContract.new
+  end
+end
+
 require "models/account"
diff --git a/activerecord/test/models/contract.rb b/activerecord/test/models/contract.rb
index f273badd85..3f663375c4 100644
--- a/activerecord/test/models/contract.rb
+++ b/activerecord/test/models/contract.rb
@@ -20,3 +20,7 @@ class Contract < ActiveRecord::Base
     @bye_count += 1
   end
 end
+
+class NewContract < Contract
+  validates :company_id, presence: true
+end
diff --git a/activerecord/test/models/post.rb b/activerecord/test/models/post.rb
index 640cdb33b4..528585fb75 100644
--- a/activerecord/test/models/post.rb
+++ b/activerecord/test/models/post.rb
@@ -324,7 +324,7 @@ class FakeKlass
       table[name]
     end
 
-    def enforce_raw_sql_whitelist(*args)
+    def disallow_raw_sql!(*args)
       # noop
     end
 
diff --git a/activerecord/test/models/price_estimate.rb b/activerecord/test/models/price_estimate.rb
index f1f88d8d8d..669d0991f7 100644
--- a/activerecord/test/models/price_estimate.rb
+++ b/activerecord/test/models/price_estimate.rb
@@ -1,6 +1,14 @@
 # frozen_string_literal: true
 
 class PriceEstimate < ActiveRecord::Base
+  include ActiveSupport::NumberHelper
+
   belongs_to :estimate_of, polymorphic: true
   belongs_to :thing, polymorphic: true
+
+  validates_numericality_of :price
+
+  def price
+    number_to_currency super
+  end
 end
diff --git a/activerecord/test/models/reply.rb b/activerecord/test/models/reply.rb
index 0ea110f4f8..0807bcf875 100644
--- a/activerecord/test/models/reply.rb
+++ b/activerecord/test/models/reply.rb
@@ -9,6 +9,10 @@ class Reply < Topic
   has_many :silly_unique_replies, dependent: :destroy, foreign_key: "parent_id"
 end
 
+class SillyReply < Topic
+  belongs_to :reply, foreign_key: "parent_id", counter_cache: :replies_count
+end
+
 class UniqueReply < Reply
   belongs_to :topic, foreign_key: "parent_id", counter_cache: true
   validates_uniqueness_of :content, scope: "parent_id"
@@ -54,10 +58,6 @@ class WrongReply < Reply
   end
 end
 
-class SillyReply < Reply
-  belongs_to :reply, foreign_key: "parent_id", counter_cache: :replies_count
-end
-
 module Web
   class Reply < Web::Topic
     belongs_to :topic, foreign_key: "parent_id", counter_cache: true, class_name: "Web::Topic"
diff --git a/activerecord/test/models/topic.rb b/activerecord/test/models/topic.rb
index 72699046f9..4aad6a4498 100644
--- a/activerecord/test/models/topic.rb
+++ b/activerecord/test/models/topic.rb
@@ -24,7 +24,7 @@ class Topic < ActiveRecord::Base
   end
 
   scope "approved_as_string", -> { where(approved: true) }
-  scope :anonymous_extension, -> {} do
+  scope :anonymous_extension, -> { } do
     def one
       1
     end
diff --git a/activerecord/test/schema/mysql2_specific_schema.rb b/activerecord/test/schema/mysql2_specific_schema.rb
index 8371ba9528..499280cb0c 100644
--- a/activerecord/test/schema/mysql2_specific_schema.rb
+++ b/activerecord/test/schema/mysql2_specific_schema.rb
@@ -14,6 +14,13 @@ ActiveRecord::Schema.define do
     end
   end
 
+  create_table :defaults, force: true do |t|
+    t.date :fixed_date, default: "2004-01-01"
+    t.datetime :fixed_time, default: "2004-01-01 00:00:00"
+    t.column :char1, "char(1)", default: "Y"
+    t.string :char2, limit: 50, default: "a varchar field"
+  end
+
   create_table :binary_fields, force: true do |t|
     t.binary :var_binary, limit: 255
     t.binary :var_binary_large, limit: 4095
@@ -29,7 +36,7 @@ ActiveRecord::Schema.define do
     t.index :var_binary
   end
 
-  create_table :key_tests, force: true, options: "ENGINE=MyISAM" do |t|
+  create_table :key_tests, force: true do |t|
     t.string :awesome
     t.string :pizza
     t.string :snacks
@@ -39,8 +46,8 @@ ActiveRecord::Schema.define do
   end
 
   create_table :collation_tests, id: false, force: true do |t|
-    t.string :string_cs_column, limit: 1, collation: "utf8_bin"
-    t.string :string_ci_column, limit: 1, collation: "utf8_general_ci"
+    t.string :string_cs_column, limit: 1, collation: "utf8mb4_bin"
+    t.string :string_ci_column, limit: 1, collation: "utf8mb4_general_ci"
     t.binary :binary_column,    limit: 1
   end
 
diff --git a/activerecord/test/schema/schema.rb b/activerecord/test/schema/schema.rb
index 266e55f682..2aaf393009 100644
--- a/activerecord/test/schema/schema.rb
+++ b/activerecord/test/schema/schema.rb
@@ -160,6 +160,7 @@ ActiveRecord::Schema.define do
   create_table :citations, force: true do |t|
     t.column :book1_id, :integer
     t.column :book2_id, :integer
+    t.references :citation
   end
 
   create_table :clubs, force: true do |t|
@@ -946,7 +947,7 @@ ActiveRecord::Schema.define do
   end
 
   [:circles, :squares, :triangles, :non_poly_ones, :non_poly_twos].each do |t|
-    create_table(t, force: true) {}
+    create_table(t, force: true) { }
   end
 
   create_table :men, force: true do |t|
diff --git a/activerecord/test/schema/sqlite_specific_schema.rb b/activerecord/test/schema/sqlite_specific_schema.rb
new file mode 100644
index 0000000000..18192292e4
--- /dev/null
+++ b/activerecord/test/schema/sqlite_specific_schema.rb
@@ -0,0 +1,11 @@
+# frozen_string_literal: true
+
+ActiveRecord::Schema.define do
+  create_table :defaults, force: true do |t|
+    t.date :fixed_date, default: "2004-01-01"
+    t.datetime :fixed_time, default: "2004-01-01 00:00:00"
+    t.column :char1, "char(1)", default: "Y"
+    t.string :char2, limit: 50, default: "a varchar field"
+    t.text :char3, limit: 50, default: "a text field"
+  end
+end