[adrianN]

I think mutation testing really shines in code bases that are already heavily tested, because it let's you discover test cases that you don't actually need. Tests are a burden since you have to adapt them when you change the behavior. With mutation testing you can prune your test code by identifying tests that test very similar behavior.

[blueyed]

Would that be done based on which (different) tests killed a particular mutant?

Often an integration test would catch the multiple mutations also being caught by (different) unit tests.

I assume that you mean that if a certain (broader) test kills the same mutants as X unit tests, those X tests are not really necessary?

I've looked into https://github.com/boxed/mutmut and https://github.com/sixty-north/cosmic-ray for Python project, and there it is only important that a mutant gets killed, but not how often and by which tests (therefore you can use `pytest -x` to continue with the next mutation after the first test failed due to it).