It has integration tests, Kafka has an embedded version for tests, just no CI setup currently. If it comes into Solr, it will just pick up Solr’s CI.
The design can work with any queuing system, but due to the various intricacies involved in the different queue implementations, adding support is best done by someone with experience with that system or involvement in building for, or access to, a real world cluster. It’s also better to add based on how most features are added vs building things that won’t be used.
