Correctly show deprecation warning for incompatible migrations

1 files changed, 12 insertions, 0 deletions

diff --git a/activerecord/test/cases/migration/compatibility_test.rb b/activerecord/test/cases/migration/compatibility_test.rb
index 6d5b6243db..d8f5b33542 100644
--- a/activerecord/test/cases/migration/compatibility_test.rb
+++ b/activerecord/test/cases/migration/compatibility_test.rb
@@ -101,6 +101,18 @@ module ActiveRecord
         assert connection.columns(:testings).find { |c| c.name == 'created_at' }.null
         assert connection.columns(:testings).find { |c| c.name == 'updated_at' }.null
       end
+
+      def test_legacy_migrations_get_deprecation_warning_when_run
+        migration = Class.new(ActiveRecord::Migration) {
+          def up
+            add_column :testings, :baz, :string
+          end
+        }
+
+        assert_deprecated do
+          migration.migrate :up
+        end
+      end
     end
   end
 end