Comment by bonoboTP
13 hours ago
Recently asked Claude Code how to do more thorough tests and described how I imagine it and it set up Hypothesis and mutmut testing. The latter is quite cool, it introduces bugs in the code like swapping values and relational operators and checks if any test catches the bug. If not, your tests are probably not thorough enough. Better than just line coverage checks.
Is my intuition correct that Mutmut has far better ROI than Hypothesis? And its as necessary as code coverage?
Mutation testing and PBT frameworks like Hypothesis are complementary. One can use the latter to find tests that kill mutants.
In large code bases it is extraordinarily slow so you have to use it sparingly