Remove unused @ClassRule container in KafkaContainerTest and use cp-kafka:6.2.1 as default

[kiview]

Since we still saw some flakiness from KafkaContainerTest in our CI, I tried to remove some of the elements that I thought of as unnecessary.

The @ClassRule annotated container was never used in any tests and was just left there for the sake of including its code in the documentation. IMO it is not useful to add test framework integration to each container module documentation, since it is not specific for the container.

The update to cp-kafka:6.2.1 was done to use a container-aware JVM so we have better guarantees for the memory configuration. Accordingly, I changed the test testConfluentPlatformVersion6 test to check instead compatibility with platform version 5, although we could consider removing this as well?

I also removed the test for the deprecated tag version constructor, but if you still want to guard against potential regressions, we can of course keep it.

[kiview]

I think no real need to keep the general testUsage() as well as the testUsageWithSpecificImage test. Since testUsageWithSpecificImage is used for inlining code in the docs, I would keep this one.

[rnorth]

The @ClassRule annotated container was never used in any tests and was just left there for the sake of including its code in the documentation. IMO it is not useful to add test framework integration to each container module documentation, since it is not specific for the container.

👍

The update to cp-kafka:6.2.1 was done to use a container-aware JVM so we have better guarantees for the memory configuration. Accordingly, I changed the test testConfluentPlatformVersion6 test to check instead compatibility with platform version 5, although we could consider removing this as well?

Seems sensible to me

I also removed the test for the deprecated tag version constructor, but if you still want to guard against potential regressions, we can of course keep it.

I think it would be a good idea to keep this, TBH...

[kiview]

Sure, I brought the test for the legacy constructor back.