I think I'm going to need to write my own framework for this.

• JUnit isn't going to play nicely with all the initialization Minecraft needs to do, and I really need to do in-world tests.
• From what I've gathered, the game test system doesn't have anything that ImmersiveMC could take advantage of beyond right-clicking (which doesn't include VR testing, among many other things).

Definitely don't need to do anything overboard. Just an in-game command to run a bunch of test functions that call asserts, which are individually catched for assertion failures is really all I need. No intention to run this in CI or anything.