+If you want to run tests from the specific directory use the +TEST_DIR+ environment variable. For example, this will run tests inside +railties/test/generators+ directory only:
+$ cd railties
+$ TEST_DIR=generators rake test
The test suite runs with warnings enabled. Ideally Ruby on Rails should issue no warning, but there may be a few, and also some from third-party libraries. Please ignore (or fix!) them if any, and submit patches that do not issue new warnings.