5 posts
Why enforcing a single mutation score across your entire codebase is a mistake, and how to set per-module thresholds that match actual risk.
Enforcing a single mutation score across your entire codebase is a great way to make your team hate testing. Run PIT or Stryker against a typical repo and…
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.
Your tests pass. Your coverage report says 87%. But your mutation score is 40%, and half your mutants are still alive. That 40% doesn't mean your code is…
cargo-mutants finds the tests that only pretend to verify your code.
You have 100% line coverage. Every branch is hit. Every function is called. Then someone changes a to a in your pricing logic, runs the tests, and they all…
Most teams don't run full mutation testing suites on every commit.
If your mutation testing suite takes four hours to run, congratulations. You've proven what everyone already suspected: your test suite has gaps. You are not…
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.
You have 90% code coverage and still got paged at 2 a.m. The unit tests passed. CI was green. The bug made it to production anyway. Coverage didn't lie, but it…