def test_singleError(self):
        """
        Test that a logged error gets reported as a test error.
        """
        test = self.MockTest('test_single')
        test(self.result)
        self.assertEqual(len(self.result.errors), 1)
        self.assertTrue(self.result.errors[0][1].check(ZeroDivisionError),
                        self.result.errors[0][1])
        self.assertEqual(0, self.result.successes)

        Test that a logged error gets reported as a test error.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_log.py