Question about mutation process

[Bob Appleyard]

OK, so here's the situation:

I have a library that does a lot of Spring-based configuration. Stuff like hooking into the bean scanning process. I would like to apply mutation testing to this library. When I run PiTest it throws up a lot of surviving mutations in this setup code. If I apply one of these mutations myself manually, however, the tests fail.

Is there anything I need to know in order to be able to diagnose and address this problem? How, and when, exactly are mutations applied? It seems like the Spring context is created once and then mutated code is run against the same context, but that is just my guess at what it is doing based on the behaviour I'm seeing.

Thanks

Bob