Clean up the test suite

[yoshuawuyts]

• we have 400 tests or so
• they're kinda nested and weird
• we're gonna be adding a bunch more tests, and it'll only get worse
• it's hard to only run a part of the suite

So we should clean up our tests a little before we refactor & add more tests :D

[tunnckoCore]

I'm ready with that. I'll look to PR here too.

For curious https://github.com/tunnckoCore/demo-minmorph/tree/master/test