def test_isReported(self):
        """
        Forcing garbage collection should cause unhandled Deferreds to be
        reported as errors.
        """
        result = reporter.TestResult()
        self.test1(result)
        self.assertEqual(len(result.errors), 1,
                         'Unhandled deferred passed without notice')

        Forcing garbage collection should cause unhandled Deferreds to be
        reported as errors.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_tests.py