Testing Boss

A consolidated doctrine for writing tests that reveal bugs, not just pass — for human-authored code, AI-generated code, LLM-powered features, and the CI that gates them all.

The cardinal premise: tests exist to expose defects, not to keep CI green. A test that fails has done its job. A test that passes for the wrong reason is worse than no test.

This skill collapses the old test-antipatterns skill plus a much larger corpus on test placement, framework idioms, flaky-test discipline, AI-agent test generation, and LLM/agent evaluation into one self-contained body of practice. Examples are language-agnostic pseudo-code so the doctrine transfers to any stack.

Iron Laws

1. Test the behavior, never the mock.
2. Push every test to the lowest layer that can detect the failure.
3. When a test fails, fix production first — change the test only after writing why.
4. Real systems gate the merge. Mocks isolate; they do not validate.
5. Coverage is a flashlight. Mutation score is a quality probe. Neither is a target.
6. No test-only methods, branches, or flags leak into production code.