[jhugo]

I think it's a big assumption that the ROI of tests in general is in the same ballpark as the ROI of static analysis.

In my experience, many tests written in commercial software engineering have ~zero or even negative ROI. This mostly applies to micro-level testing like unit tests; macro-level testing like integration tests can be fantastically valuable and I've even come to believe that they're the only type of tests most teams should spend time writing.

[pmarreck]

It depends on how you design your software and where the API surfaces are and how isolated the pieces can be made to be.

Which, if you're writing unit tests at the same time as the unit under test, leads naturally to pro-isolation, pro-modular designs, which are both easier to test, more reliable and generally have a more concise purpose.

[notacoward]

Well, we were talking about regression tests, which are much closer to integration tests than unit tests, so I'm not sure we actually disagree. Writing regression tests is still valuable, and still too rare.