def test_errorByDefault(self):
        """
        L{DirtyReactorAggregateError}s are reported as errors with the default
        Reporter.
        """
        result = reporter.Reporter(stream=self.output)
        result.addError(self.test, self.dirtyError)
        self.assertEqual(len(result.errors), 1)
        self.assertEqual(result.errors[0][1], self.dirtyError)

        L{DirtyReactorAggregateError}s are reported as errors with the default
        Reporter.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_reporter.py