'L{ftp.FTPClient.makeDirectory} returns a L{Deferred} which is errbacked
with L{CommandFailed} if the server returns an error response code.'

def test_failedMakeDirectory(self):

    self._testLogin()
    d = self.client.makeDirectory('/spam')
    self.assertEqual(self.transport.value(), 'MKD    /spam\r\n')
    self.client.lineReceived('550    PERMISSION    DENIED')
    return self.assertFailure(d, ftp.CommandFailed)
