Writing tests for legacy code can be hard and time‑consuming. Even with Michael Feathers’ guidance, the task remains a challenge.

So I wondered whether modern language features and tooling could finally make it easy. The result surprised me and completely changed how I work with legacy systems.

SpecRec automatically generates characterisation tests with minimal code interventions that give you a robust safety net, letting you refactor large parts of a codebase in hours instead of weeks.

I’ll walk through the technique, show a real‑world use case, and explain how you can adopt SpecRec in your own projects.