Github user jbertram commented on the issue:
https://github.com/apache/activemq-artemis/pull/2491
The test code is correct. The state kept in an unclean session includes the
subscriptions which is why the test doesn't create a subscription before trying
to receive the message. If the broker doesn't properly clean the session state
when the client connects with cleanSession=true then it will receive a message
and the test will fail.---
