Legacy-Code on Tokenisehttps://tokenise.rosvetic.com/tags/legacy-code/Recent content in Legacy-Code on TokeniseHugoen-gbFri, 09 Oct 2026 11:06:00 +0000Pin legacy behaviour before an agent refactors it, then grade the tests with mutation testinghttps://tokenise.rosvetic.com/posts/characterization-tests-mutation-check/Fri, 09 Oct 2026 11:06:00 +0000https://tokenise.rosvetic.com/posts/characterization-tests-mutation-check/<p>You&rsquo;re about to refactor a shipping calculator that nobody on the team wrote and nobody wants to touch. You ask an agent for tests first, it hands back four neat ones, they pass, and you start the refactor with a green light that means almost nothing. Four tests can&rsquo;t pin forty decisions.</p>