test-quality

5 articles

May 30, 2026

Auth code needs 90% mutation coverage. Your string utils don't.

Why enforcing a single mutation score across your entire codebase is a mistake, and how to set per-module thresholds that match actual risk.

May 29, 2026

Your Tests Pass. Your Mutation Score Is 40%. Here's What Surviving Mutants Are Actually Telling You.

Code coverage says you're safe. Mutation testing says your tests are mostly decoration. Here's how surviving mutants expose the gap, and how to close it.

deep-dives mutation-testing surviving-mutants test-quality

May 28, 2026

Mutation Testing in Rust Works, but Your Compile Times Will Hate You

cargo-mutants finds the tests that only pretend to verify your code.

deep-dives mutation-testing rust cargo-mutants test-quality

May 27, 2026

Mutation testing takes 4 hours. How do teams actually use it in CI?

Most teams don't run full mutation testing suites on every commit.

deep-dives mutation-testing ci-cd test-quality

May 22, 2026

Your Unit Tests Pass. Your Production Code Is Still Broken.

Code coverage metrics create a false sense of security. Here's why unit tests miss the bugs that actually cost you sleep, and what to test instead.

deep-dives unit-testing test-quality bug-prevention