I feel like we should have more tests, and more rigorous tests, for this new feature. Can we add some more to exercise this?

I added tests that dump non-argument locals on side exits 5b621b1 and one that checks cfp->pc 7916f3d.

Another test target would be the content of dumped locals. But to test the content of locals from a callee, we'd need to load a C extension in test/-ext-/debug/test_debug.rb like YJIT does. We're still not ready for running the current make test-all with ZJIT enabled.

Do you have other things you want to be tested in mind? We could just "have more tests" as you said, but I generally try to avoid bloating the number of tests by adding meaningless/duplicated test cases.

❌ Tests Failed

✖️no tests failed ✔️61994 tests passed(1 flake)

I don't mean to bloat the tests but did not (at the time of comment) have a good set of recommendations for things to test. 2 tests for a bunch of new functionality just seemed a bit light. I can imagine having a bunch of dark untested corner cases

I think we should aim for enabling make btest, make test-all, and make test-spec on CI with ZJIT as soon as possible. They would test more corner cases than we can think of and write in test_zjit.rb. Even then, you'd encounter dark untested corner cases though. Anything we can come up with today is probably not a dark corner case.

This project should have got the test setup much earlier, but we were so focused on keeping generated code optimal that we never had the "rigorous tests" we could have got for free. This PR should bring us much closer to having it.

You approved the PR and the CI passed, so I'll merge this PR to unblock your stacked PR. We can add more tests as we come up with untested scenarios that are worth testing.