def test_successResultOfWithFailureHasTraceback(self):
        """
        L{SynchronousTestCase.successResultOf} raises a
        L{SynchronousTestCase.failureException} that has the original failure
        traceback when called with a L{Deferred} with a failure result.
        """
        try:
            self.successResultOf(fail(self.failure))
        except self.failureException as e:
            self.assertIn(self.failure.getTraceback(), str(e))

        L{SynchronousTestCase.successResultOf} raises a
        L{SynchronousTestCase.failureException} that has the original failure
        traceback when called with a L{Deferred} with a failure result.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_assertions.py