def test_postClassCleanupWithPendingCallErrors(self):
        """
        The post-class cleanup method call C{addError} on the result with a
        L{DirtyReactorAggregateError} Failure if there are pending calls.
        """
        delayedCall = DelayedCall(300, lambda: None, (), {},
                                  lambda x: None, lambda x: None,
                                  seconds=lambda: 0)
        delayedCallString = str(delayedCall)
        reactor = StubReactor([delayedCall], [])
        test = object()
        reporter = StubErrorReporter()
        jan = _Janitor(test, reporter, reactor=reactor)
        jan.postClassCleanup()
        self.assertEqual(len(reporter.errors), 1)
        self.assertEqual(reporter.errors[0][1].value.delayedCalls,
                          [delayedCallString])

        The post-class cleanup method call C{addError} on the result with a
        L{DirtyReactorAggregateError} Failure if there are pending calls.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_util.py