WP Mutate

Mutation testing changes your source code in small ways and re-runs the tests. If the suite still passes, the mutant survived — the code path is executed but nothing asserts its behaviour. Line coverage says the code ran; mutation testing says the tests would notice if it broke.

When to use

Use this skill when:

• Test coverage looks healthy but bugs still ship.
• You want to know whether tests actually assert behaviour or just execute lines.
• You need evidence that security controls (capability checks, nonces, sanitization) are genuinely tested.
• You want a regression ratchet on test quality, not just test quantity.

Do not use this skill to create a test suite from scratch. If there are no tests, stop and point the user at prepare-wordpress.