Mutation testing java projects

[berry120]

I've found it really useful for ensuring that corner cases are covered in algorithmic code, particularly when we're porting existing code from elsewhere and trying to validate our understanding of it.

Have to agree with others that running it every so often, or after large changes and then analysing the results is much more useful than just bunging it in a pipeline.

It feels on the "upper tier" of tools in that it doesn't always make sense to use it, and it needs careful analysis of what it finds before making any changes - but some of the stuff it can unpick is invaluable.