Yep, testing definitely has a hugely decreasing marginal value. I personally like the approach of writing a small amount of "obvious" tests to detect large fun

Yep, testing definitely has a hugely decreasing marginal value. I personally like the approach of writing a small amount of "obvious" tests to detect large functional breakage, and add a test for a bug once it's been identified aka a regression test. Imo it's maximum test value per effort. Of course it depends on how impactful a bug could be.