def test_removeSafelyNoTrialMarker(self):
        """
        If a path doesn't contain a node named C{"_trial_marker"}, that path is
        not removed by L{util._removeSafely} and a L{util._NoTrialMarker}
        exception is raised instead.
        """
        directory = self.mktemp().encode("utf-8")
        os.mkdir(directory)
        dirPath = filepath.FilePath(directory)
        self.assertRaises(util._NoTrialMarker, util._removeSafely, dirPath)

        If a path doesn't contain a node named C{"_trial_marker"}, that path is
        not removed by L{util._removeSafely} and a L{util._NoTrialMarker}
        exception is raised instead.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/trial/test/test_util.py