I’m going to add the API Server as an actor to my first test sequence to give some granularity as to what I’m actually testing.

For features like websocket interactions, a single full-stack smoke test is almost essential to confirm that things are going as planned, even if the individual parts of the interaction are also covered by unit tests.

How to test at the correct level?

As many things in life, deciding what to test at each level of testing is a trade-off: