I am trying to capture the idea that opinionated tests assert invariants and contracts at integration boundaries, while coverage-driven suites often spend effor

I am trying to capture the idea that opinionated tests assert invariants and contracts at integration boundaries, while coverage-driven suites often spend effort on shallow checks. The goal is fewer but stronger tests that actually prevent regressions. Here is one attempt at defining a TESTING.md that I pass to Claude Code [0]. Honestly, it is different from what I now use in other projects. For example, I have found that mutation tests are rarely worth the added complexity. I have not yet found a good way to enforce a deterministic gate that only permits “good” tests, so I settle on defining expectations in a markdown file that I pass to whichever coding agent I am using. [0] https://github.com/Airbolt-AI/airbolt/blob/main/TESTING.md https://github.com/Airbolt-AI/airbolt/blob/main/TESTING.md