def test_walkCyclicalSymlink(self):
        """
        Verify that walking a path with a cyclical symlink raises an error
        """
        self.createLinks()
        self.symlink(self.path.child(b"sub1").path,
                     self.path.child(b"sub1").child(b"sub1.loopylink").path)
        def iterateOverPath():
            return [foo.path for foo in self.path.walk()]
        self.assertRaises(filepath.LinkError, iterateOverPath)

        Verify that walking a path with a cyclical symlink raises an error
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_paths.py