Code Quality

Posts on the tooling that catches problems before they reach production — static analysis, testing frameworks, code-metric analyzers, and the release plumbing that gates all of it. Some of it is Go-specific (Ginkgo, golangci-lint, kyber, TDD-shape). Some of it isn’t (nasm-lint for NASM assembly, semantic-release as a language-agnostic contract). The common thread is: the quality gate should live in the loop where the code is written, not in a review that happens after the fact.

Mutation testing: grading the tests, not the code

The anchor post of the mutation-testing series. What mutation testing actually measures, why it exists as a complement to line coverage, when to reach for it, and the specific classes of test-suite weakness it uncovers — written to stand alone regardless of your language.

Mutation testing in Rust: getting started with cargo-mutants

The Rust chapter of the mutation-testing series: what the technique measures, why the number is stronger than line coverage, and how to run cargo-mutants against a real Rust crate in five minutes.

Mutation testing in Go: getting started with gremlins

The Go companion to the mutmut post: what mutation testing actually measures, how gremlins produces the score, and how to run it against a real Go module in five minutes.

Mutation testing in Python: getting started with mutmut

Line coverage tells you where the tests went. Mutation testing tells you whether the tests you have would notice if the code were wrong. A plain-language getting-started guide with mutmut.

Black-box unit tests: testing behavior, not implementation

Unit tests that break every time you refactor are describing the implementation, not the behavior. A senior engineer’s playbook for writing black-box tests that survive.