Test eval metrics

[valedan]

We should ensure that the eval metrics are sensible, and that they are doing what we expect.

Probably makes sense to write unit tests for each of them.

More info needed to define acceptance criteria?

[valedan]

@rusheb Whoops, converting your draft to an issue made me the owner. 🤯

When you say eval metrics here, you're referring to the functions in pathdist.py?

[valedan]

If that's the case it should be fairly straightforward, but we should do it after #99 to avoid conflicts

[rusheb]

I think I initially raised this based on a comment somebody made in a meeting, so I'm not exactly sure what I was referring to. But it would make sense if it was the functions in pathdist.py