TestCase.skipTest() will raise a SkipTest exception, which is not caught in _cleaning_debug, so the _post_teardown() call is skipped. Also apparently cleanups registered with TestCase.addCleanup() will not be run. If setup done in _pre_setup needs to be undone in _post_teardown (or in cleanups scheduled with addCleanup()), that will not happen for tests skipped with skipTest().

This does not apply to tests skipped with a @unittest.skip decorator.

For comparison, nose runs _post_teardown methods for tests skipped with skipTest().