mutmut feat: allow supplying options on cli tool

Overview

Allow supplying paths-to-mutate (as comma separated values), tests-dir, and debug 'options' through the cli tool

Example:

mutmut --paths-to-mutate <path1,path2> --tests-dir <path> --debug run

Aug 13 '25 15:08 souradeep-das

I don't think this is a good idea. Mutmut 2 had it and I consider that a mistake.

Aug 13 '25 16:08 boxed

Thanks for the feedback! Any particular context/reasons why this could be bad?

Aug 13 '25 16:08 souradeep-das

Just that the conf is annoying to get right and then you forget about it and your life sucks :)

And it won't work with the interactive UI either.

Aug 13 '25 17:08 boxed

How would you recommend filtering out tests? Some of ours run extremely long and aren't really necessary to run for every mutation.

Aug 15 '25 14:08 SamWilsn

Ideally you would keep the mutations directory between runs, and then mutmut will automatically know which mutants to check. You can also set the stack depth to something lower to make it accept fewer tests.

Aug 16 '25 08:08 boxed

Sorry, not sure I follow. If I have a test function, test_really_really_long_running, how do I exclude it from the tests mutmut runs? It doesn't have a particularly deep stack compared to other tests, just a lot more iterations. In pytest, we use -m "not slow".

@pytest.mark.slow
def test_really_really_long_running():
   ...

Aug 18 '25 14:08 SamWilsn

https://github.com/boxed/mutmut/issues/423 see the discussion there. Options in the config makes sense to me.

Aug 18 '25 15:08 boxed