Testing guide

[krambono]

I would really appreciate having a guide on testing. The missing part in the documentation is a pain point for me.

I think what is important to mention is what to test and how to test it.

To me, what is important to test is:

When a transition happens, do I get the expected state?
Are side effects performed well?
Is the context mutated as expected?

And how to do it when the state machine grows, when you have a lot of states, invoked, spawned actors, etc.

[davidkpiano]

Our current testing docs are here: https://stately.ai/docs/testing

Can you please post suggestions as issues here? https://github.com/statelyai/docs/issues/new