High-Signal Tests

Single goal: every test in the repo must be able to catch a real bug. E2E and integration tests carry the load when the repo has them. Unit tests stay only for written failure modes that the higher-level tests miss.

A low-signal unit test passes or fails together with the code it copies. It costs upkeep, slows refactors, and gives false trust. Delete it.

The Policy

1. Use only the test setups the repo already has. Do not add an E2E setup (for example Playwright) or an integration setup (for example Testcontainers) on your own. Suggest one if a gap is serious, then wait for approval.
2. Never write unit tests after you write code. A test written after the code only restates the code. It does not find bugs.
3. Prefer E2E and integration tests when those setups exist. Use them to prove that complex features work through real entry points and real services.
4. End each E2E test with an artifact. The artifact must be verifiable and repeatable. See e2e-artifacts.md. Applies only when an E2E setup exists.
5. Test a unit in isolation only when you must. First, write down all the ways it can fail. Then write the code. Each isolated test checks one listed failure. See failure-modes.md.

Rules 3 and 4 are enforceable only for setups that exist. Rules 1, 2, and 5, and the unit-test prune, always apply.

Modes

Pick from the request: