Prune low-signal unit tests aggressively. Agents often write tests that restate the implementation, always pass, break on every refactor, and add little protection beyond existing tests.
Prefer a smaller suite that protects behavior over a large suite that protects coverage numbers.
Keep a test only if all of these are true:
- It protects a specific observable behavior, invariant, or contract.
- There is a concrete, credible regression its assertions would detect.
- Its expected results are justified independently of the implementation under test.
- It adds meaningful value beyond other retained tests: a distinct failure mode, an important edge case, or substantially faster, more reliable, or more precise feedback.