1 files changed, 131 insertions, 13 deletions
diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
index 017ee7951e..ff2a694e66 100644
--- a/activerecord/test/cases/migration/compatibility_test.rb
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -12,6 +12,7 @@ module ActiveRecord
       def setup
         super
         @connection = ActiveRecord::Base.connection
+        @schema_migration = @connection.schema_migration
         @verbose_was = ActiveRecord::Migration.verbose
         ActiveRecord::Migration.verbose = false
 
@@ -38,7 +39,7 @@ module ActiveRecord
         }.new
 
         assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
-        assert_raise(StandardError) { ActiveRecord::Migrator.new(:up, [migration]).migrate }
+        assert_raise(StandardError) { ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate }
         assert connection.index_exists?(:testings, :foo, name: "custom_index_name")
       end
 
@@ -53,7 +54,7 @@ module ActiveRecord
         }.new
 
         assert connection.index_exists?(:testings, :bar)
-        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
         assert_not connection.index_exists?(:testings, :bar)
       end
 
@@ -67,7 +68,7 @@ module ActiveRecord
           end
         }.new
 
-        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
 
         assert_not connection.index_exists?(:more_testings, :foo_id)
         assert_not connection.index_exists?(:more_testings, :bar_id)
@@ -84,10 +85,10 @@ module ActiveRecord
           end
         }.new
 
-        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
 
-        assert connection.columns(:more_testings).find { |c| c.name == "created_at" }.null
-        assert connection.columns(:more_testings).find { |c| c.name == "updated_at" }.null
+        assert connection.column_exists?(:more_testings, :created_at, null: true)
+        assert connection.column_exists?(:more_testings, :updated_at, null: true)
       ensure
         connection.drop_table :more_testings rescue nil
       end
@@ -101,10 +102,27 @@ module ActiveRecord
           end
         }.new
 
-        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
 
-        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
-        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+        assert connection.column_exists?(:testings, :created_at, null: true)
+        assert connection.column_exists?(:testings, :updated_at, null: true)
+      end
+
+      if ActiveRecord::Base.connection.supports_bulk_alter?
+        def test_timestamps_have_null_constraints_if_not_present_in_migration_of_change_table_with_bulk
+          migration = Class.new(ActiveRecord::Migration[4.2]) {
+            def migrate(x)
+              change_table :testings, bulk: true do |t|
+                t.timestamps
+              end
+            end
+          }.new
+
+          ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+          assert connection.column_exists?(:testings, :created_at, null: true)
+          assert connection.column_exists?(:testings, :updated_at, null: true)
+        end
       end
 
       def test_timestamps_have_null_constraints_if_not_present_in_migration_for_adding_timestamps_to_existing_table
@@ -114,10 +132,72 @@ module ActiveRecord
           end
         }.new
 
-        ActiveRecord::Migrator.new(:up, [migration]).migrate
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:testings, :created_at, null: true)
+        assert connection.column_exists?(:testings, :updated_at, null: true)
+      end
+
+      def test_timestamps_doesnt_set_precision_on_create_table
+        migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def migrate(x)
+            create_table :more_testings do |t|
+              t.timestamps
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:more_testings, :created_at, null: false, **precision_implicit_default)
+        assert connection.column_exists?(:more_testings, :updated_at, null: false, **precision_implicit_default)
+      ensure
+        connection.drop_table :more_testings rescue nil
+      end
+
+      def test_timestamps_doesnt_set_precision_on_change_table
+        migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def migrate(x)
+            change_table :testings do |t|
+              t.timestamps default: Time.now
+            end
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+        assert connection.column_exists?(:testings, :created_at, null: false, **precision_implicit_default)
+        assert connection.column_exists?(:testings, :updated_at, null: false, **precision_implicit_default)
+      end
+
+      if ActiveRecord::Base.connection.supports_bulk_alter?
+        def test_timestamps_doesnt_set_precision_on_change_table_with_bulk
+          migration = Class.new(ActiveRecord::Migration[5.2]) {
+            def migrate(x)
+              change_table :testings, bulk: true do |t|
+                t.timestamps
+              end
+            end
+          }.new
+
+          ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+          assert connection.column_exists?(:testings, :created_at, null: false, **precision_implicit_default)
+          assert connection.column_exists?(:testings, :updated_at, null: false, **precision_implicit_default)
+        end
+      end
+
+      def test_timestamps_doesnt_set_precision_on_add_timestamps
+        migration = Class.new(ActiveRecord::Migration[5.2]) {
+          def migrate(x)
+            add_timestamps :testings, default: Time.now
+          end
+        }.new
+
+        ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
 
-        assert connection.columns(:testings).find { |c| c.name == "created_at" }.null
-        assert connection.columns(:testings).find { |c| c.name == "updated_at" }.null
+        assert connection.column_exists?(:testings, :created_at, null: false, **precision_implicit_default)
+        assert connection.column_exists?(:testings, :updated_at, null: false, **precision_implicit_default)
       end
 
       def test_legacy_migrations_raises_exception_when_inherited
@@ -141,6 +221,35 @@ module ActiveRecord
         end
       end
 
+      if ActiveRecord::Base.connection.supports_comments?
+        def test_change_column_comment_can_be_reverted
+          migration = Class.new(ActiveRecord::Migration[5.2]) {
+            def migrate(x)
+              revert do
+                change_column_comment(:testings, :foo, "comment")
+              end
+            end
+          }.new
+
+          ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+          assert connection.column_exists?(:testings, :foo, comment: "comment")
+        end
+
+        def test_change_table_comment_can_be_reverted
+          migration = Class.new(ActiveRecord::Migration[5.2]) {
+            def migrate(x)
+              revert do
+                change_table_comment(:testings, "comment")
+              end
+            end
+          }.new
+
+          ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
+
+          assert_equal "comment", connection.table_comment("testings")
+        end
+      end
+
       if current_adapter?(:PostgreSQLAdapter)
         class Testing < ActiveRecord::Base
         end
@@ -153,12 +262,21 @@ module ActiveRecord
           }.new
 
           Testing.create!
-          ActiveRecord::Migrator.new(:up, [migration]).migrate
+          ActiveRecord::Migrator.new(:up, [migration], @schema_migration).migrate
           assert_equal ["foobar"], Testing.all.map(&:foo)
         ensure
           ActiveRecord::Base.clear_cache!
         end
       end
+
+      private
+        def precision_implicit_default
+          if current_adapter?(:Mysql2Adapter)
+            { precision: 0 }
+          else
+            { precision: nil }
+          end
+        end
     end
   end
 end