I'm the author of mutmut, the primary mutation tester for python, so I think I can speak a bit on this.
It's quite straight forward to do MT in software. I've done quite a bit of it for specific libraries that I've built (iommi, tri.struct, and internal code). A big advantage in my book of MT over PBT is the much lower cognitive overhead for MT and that you can know you have done it completely. The second may be just a false sense of security or an emotional blanket, but still.
Does that only work in Python though? What about compiled languages? You don't really want to have to recompile your whole project again for every line you change...
mutmut right now is implemented by writing changes to disk and starting new processes. But you can implement it via "mutation schemata" where you functionally compile all possible mutants ahead of time, plus the original function, and replace the original function with a trampoline that either calls the original or one of the mutants depending on some external state.
I have a prototype of mutmut that does this and it's 10 to 100x faster. It does have the downside of not being able to mutate stuff like static global variables and such though.
It's quite straight forward to do MT in software. I've done quite a bit of it for specific libraries that I've built (iommi, tri.struct, and internal code). A big advantage in my book of MT over PBT is the much lower cognitive overhead for MT and that you can know you have done it completely. The second may be just a false sense of security or an emotional blanket, but still.
I have written about mutation testing a few times: https://kodare.net/2019/04/10/mutation-vs-property-based-tes... https://kodare.net/2018/11/18/the-missing-mutant-a-performan... https://kodare.net/2016/12/12/mutation-testing-in-practice.h... and my talk on mutmut from pycon sweden is on youtube: https://www.youtube.com/watch?v=fZwB1gQBwnU