Certainly do... we can chat if you like (tomorrow?)

The physics lists tests (if you want to talk about how to do it) I think fit nicely as python unit tests.

Fine it can be done with unittest module. I need to bring the code across, that means making sure I understand how simulation does geometries and such like.

Note in my jargon this is not a unit test. A unit test tests the smallest possible unit, i.e. a function.

This is an application level test (checking that we have integrated G4 correctly with simulation). That's really testing the design is correct.

We can do application tests using python unittest library of course, which I think was your point.