def test_noDuplicateAddsResult(self):
        redirect = _RedirectLogsForTrial(FakeSys(["trial"], b""), LogPublisher())
        destination = redirect()
        self.addCleanup(removeDestination, destination)
        result = redirect()
        self.assertIs(result, None)
If a destination has already been added, calling L{redirectLogsForTrial}
dataset/ETHPy150Open ClusterHQ/eliot/eliot/tests/test_twisted.py/RedirectLogsForTrialTests.test_noDuplicateAddsResult