How to automate end-to-end tests?

[motiz88]

I would love to have strong tests that serve to ensure correctness, catch regressions and eventually drive automated releases.

We may need a way to mock hardware MIDI devices, so that we can exercise the code all the way down through the various layers - JS, React bridge, Java/ObjC and platform APIs. I'm not aware of an easy way to do this, though.

Would love to read others' thoughts on possible testing schemes.