def test_uncleanWarningsOffByDefault(self):
        """
        By default Trial sets the 'uncleanWarnings' option on the runner to
        False. This means that dirty reactor errors will be reported as
        errors. See L{test_reporter.DirtyReactorTests}.
        """
        self.parseOptions([])
        runner = self.getRunner()
        self.assertNotIsInstance(runner._makeResult(),
                                 reporter.UncleanWarningsReporterWrapper)

        By default Trial sets the 'uncleanWarnings' option on the runner to
        False. This means that dirty reactor errors will be reported as
        errors. See L{test_reporter.DirtyReactorTests}.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_runner.py