Audit Tautological Tests

A tautological test is one where you delete the implementation and the test still passes — because the test is asserting against its own mocks, not against real behavior. These tests give false confidence and let bugs ship.

When to use

• A bug shipped to code that had "100% coverage."
• High test coverage + high bug rate is a smell.
• Reviewing a PR with many new tests that look suspicious.
• Refactor risk-assessment: which tests would actually catch a regression?

When NOT to use

• Test suite is genuinely good and bugs are escaping for other reasons (test environment doesn't match prod).
• Looking for slow tests, flaky tests, or coverage gaps — different audits.

The five test smells

1. The mock is the implementation