Retained message test, with QoS=2.

retained.py

#!/usr/bin/python

import mosquitto
import time

pub_sent = False

def pub_on_connect(mosq, obj, rc):
    mosq.publish("/A/B", "message one", 2, True)
    mosq.publish("/A/B", "message two", 2, True)
    (rc, mid) = mosq.publish("/A/B", "message three", 2, True)
    mosq.user_data_set(mid)

def on_publish(mosq, obj, mid):
    global pub_sent
    print("published: "+str(mid))
    if mid == obj:
        pub_sent = True


def sub_on_connect(mosq, obj, rc):
    mosq.subscribe("/A/B", 2)

def on_message(mosq, obj, msg):
    print(msg.topic+" "+str(msg.qos)+" "+str(msg.payload))

pub = mosquitto.Mosquitto()
pub.on_connect = pub_on_connect
pub.on_publish = on_publish
pub.connect("test.mosquitto.org")
pub.loop_start()

while pub_sent == False:
    time.sleep(0.1)

sub = mosquitto.Mosquitto()
sub.on_connect = sub_on_connect
sub.on_message = on_message
sub.connect("test.mosquitto.org")

sub.loop_forever()