How to test behavior with QoS 1 with connection drop-out mid-publish?

[philCryoport]

Hi there,

We are considering AWS IoT Core.

Our Quality department has asked for us to run a Operational Quality test between the MQTT client and AWS IoT MQTT broker so that we can document evidence of the following behavior:

• IF
  • QoS 1 is enabled for publishing from a MQTT client to a MQTT broker's topic
• AND
  • WHILE the MQTT client is publishing a message to that MQTT broker's topic
  • IF the connection drops mid-publish
• THEN
  • The MQTT broker will not accept the partial message -- and thus the message won't be delivered to the topic
  • AND
  • The MQTT client will NOT receive a PUBACK

I looked through the code and the only thing I could find that was close to this was

paho.mqtt.testing/interoperability/client_test.py

Line 322 in 252b6b9

def test_redelivery_on_reconnect(self):

...but that only tests if there is no connection to begin with.

In contrast, what I'm seeking is a way to demonstrate behavior:

• IF
  • The connection was there to begin with
• AND THEN
  • Mid-publish, the connection drops

Help?

[icraggs]

One way to do this, is to use a network proxy between the client and broker which will break the connection at the appropriate point. There is such a simple proxy in the testing repo and the C client repo (paho.mqtt.c) written in Python. It can be altered to cut the connection at the point you want.

[philCryoport]

One way to do this, is to use a network proxy between the client and broker which will break the connection at the appropriate point. There is such a simple proxy in the testing repo and the C client repo (paho.mqtt.c) written in Python. It can be altered to cut the connection at the point you want.

Neat! I'll try it. Thank you!