As a brief note to self, I started looking into writing my own Scala testing framework, mostly because the main current frameworks are not currently available for Scala 3.0-M3. That led me to this Minitest blog post, the Minitest repository, and finally this sbt test-interface repository. It looks like if you want to write your own testing framework to work with sbt, that interface is what you need to implement.
I just tested Minitest with Scala 3, and it seems to work, so for now I’m not going any further. But I was happy to find that interface project, because I have often wondered what it would take to write a testing framework to work with sbt.