def test_removeDirectory(self):
        """
        L{ftp.FTPClient.removeDirectory} sends a I{RMD} command to the server
        for the indicated directory and returns a Deferred which fires after
        the server sends a 250 response code.
        """
        self._testLogin()
        d = self.client.removeDirectory('/tmp/test')
        self.assertEqual(self.transport.value(), b'RMD /tmp/test\r\n')
        response = '250 Requested file action okay, completed.'
        self.client.lineReceived(response.encode(self.client._encoding))
        return d.addCallback(self.assertEqual, [response])

        L{ftp.FTPClient.removeDirectory} sends a I{RMD} command to the server
        for the indicated directory and returns a Deferred which fires after
        the server sends a 250 response code.
        
stackoverflow/venv/lib/python3.6/site-packages/twisted/test/test_ftp.py