def test_crossMountMoveTo(self):
        """
        C{moveTo} should be able to handle C{EXDEV} error raised by
        C{os.rename} when trying to move a file on a different mounted
        filesystem.
        """
        invokedWith = self.setUpFaultyRename()
        # Bit of a whitebox test - force os.rename, which moveTo tries
        # before falling back to a slower method, to fail, forcing moveTo to
        # use the slower behavior.
        self.test_moveTo()
        # A bit of a sanity check for this whitebox test - if our rename
        # was never invoked, the test has probably fallen into disrepair!
        self.assertTrue(invokedWith)

        C{moveTo} should be able to handle C{EXDEV} error raised by
        C{os.rename} when trying to move a file on a different mounted
        filesystem.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_paths.py