def testChAttrs(self):
        """
        Check that 'ls -l' output includes the access permissions and that
        this output changes appropriately with 'chmod'.
        """
        def _check(results):
            self.flushLoggedErrors()
            self.assertTrue(results[0].startswith(b'-rw-r--r--'))
            self.assertEqual(results[1], b'')
            self.assertTrue(results[2].startswith(b'----------'), results[2])
            self.assertEqual(results[3], b'')

        d = self.runScript('ls -l testfile1', 'chmod 0 testfile1',
                           'ls -l testfile1', 'chmod 644 testfile1')
        return d.addCallback(_check)
        # XXX test chgrp/own

        Check that 'ls -l' output includes the access permissions and that
        this output changes appropriately with 'chmod'.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/conch/test/test_cftp.py