def METHOD_NAME(self, mocked):
    """
    Test MQTT Backend send method
    """
    from_user = _create_user('Bob')
    to_user = _create_user('Alice')
    instance = _create_message(from_user, to_user, 'I love oov')
    mqtt = MQTTBackend(options={
        'HOST': 'localhost',
        'PORT': 8883,
        'SECURE': True,
        'CA_CERT_FILE': 'cacert.pem',
        'CERT_FILE': 'emq.pem',
        'KEY_FILE': 'emq.key'
    })
    mqtt.send(instance=instance)
    self.assertTrue(mocked.called)
    args, kwargs = mocked.call_args_list[0]
    self.assertEqual(mqtt.get_topic(instance), args[0])
    self.assertEqual(get_payload(instance), kwargs['payload'])
    self.assertEqual('localhost', kwargs['hostname'])
    self.assertEqual(8883, kwargs['port'])
    self.assertEqual(0, kwargs['qos'])
    self.assertEqual(False, kwargs['retain'])
    self.assertDictEqual(
        dict(ca_certs='cacert.pem',
             certfile='emq.pem',
             keyfile='emq.key',
             tls_version=ssl.PROTOCOL_TLSv1_2,
             cert_reqs=ssl.CERT_NONE),
        kwargs['tls'])