def setUp(self):
        """
        Patch the L{ls} module's time function so the results of L{lsLine} are
        deterministic.
        """
        self.now = 123456789
        def fakeTime():
            return self.now
        self.patch(ls, 'time', fakeTime)

        # Make sure that the timezone ends up the same after these tests as
        # it was before.
        if 'TZ' in os.environ:
            self.addCleanup(operator.setitem, os.environ, 'TZ', os.environ['TZ'])
            self.addCleanup(time.tzset)
        else:
            def cleanup():
                # os.environ.pop is broken!  Don't use it!  Ever!  Or die!
                try:
                    del os.environ['TZ']
                except KeyError:
                    pass
                time.tzset()
            self.addCleanup(cleanup)

        Patch the L{ls} module's time function so the results of L{lsLine} are
        deterministic.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_cftp.py