def test_wasSuccessfulFalseAfterErrors(self):
        """
        wasSuccessful() becomes False after errors have been reported.
        """
        try:
            1 / 0
        except ZeroDivisionError:
            self.result.addError(self.test, sys.exc_info())
        self.assertEqual(False, self.result.wasSuccessful())

        wasSuccessful() becomes False after errors have been reported.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py