Extract in-jvm DTest API and tests into a separate repository that is shared between Cassandra branches. Tests themselves should be buildable using just API, which is not the case now, since cluster creation relies on impl package, since we do not have factories / constructors in API.
Main goals we’re trying to achieve:
1. We should be able to fail a build on API incompatibility between versions
2. Make it as easy as possible to detect break APIs between versions.
3. Make development of tests based on in-jvm framework simpler
4. Reduce surface area of impact when making modifications to tests
Potentially, we’d also like to use a plugin to detect API incompatibilities between in-jvm DTest API and in-branch implementations, and start running tests using shared in-jvm test repository with each existing implementation in the branch. This entails both running tests for all branches whenever there’s a change in tests jar and running tests for a specific branch whenever the branch has changed.