JANUS unit tests

[lsoucasse]

The tests we have for now are global examples and we might think of breaking those into smaller pieces so that it makes bugs easier to track.

[stefsmeets]

The current tests take about 7 minutes on my system, which is too long too be useful. I think not only splitting them up, but also making a smaller test data set that runs in a shorter amount of time (couple of seconds) would be nice.

[stefsmeets]

One cycle of instellation alone takes 45 seconds, and the code does 7 cycles 😅

[stefsmeets]

It's not entirely clear how the test can be broken into smaller pieces, it's mostly lots of setup, a few lines of code, and then clean-up. What we can do is parametrize the tests. I'm going to have a go at this to get a bit of a feel for the code.

[nichollsh]

It would be good if any tests of JANUS use different platforms or distributions. We are more likely to catch issues such as: FormingWorlds/MORS#22