I was originally using testcontainers for these tests, but moved them to use an embedded server years ago since we weren't able to use Docker in tests from ci.wildfly.org.

The embedded server is very fiddly to maintain, and locks us into a Kafka version.
Also there is a FileBasedStateStore.java which you need to override for Windows tests to work. Since running the Kafka broker on Windows is not supported, the fixes in this file will never be pulled in upstream. Also, the 'raw' upstream file keeps on changing all the time, and more recently is getting renamed and refactored in other ways.

Moving to Testcontainers will ensure that Kafka always runs in a Linux environment (in a container). Although AIUI testcontainers tests will be skipped on our Windows CI jobs, I think the benefit of having a simpler setup is worth the less coverage. And it will still be able to run the tests in a Windows environment where Docker actually is available.