Add service name validation

[fhoekstra]

Implements #59.
I just couldn't wait.

I do have doubts about one "missing" test case. What if the service name is invalid (that would cause a ValueError) and it has not been called (that would raise AssertionError).

I think I am fine with any of them being called, or both.

[fhoekstra]

Added that "missing" case in b070528, by calling pytest.raises with a tuple of assertions.

[HelloThisIsFlo]

Hey 👋

For now, you can consider this project unmaintained, unfortunately.

I haven't had time to maintain this repo in the last few years, in good parts because I moved home and I haven't had a HomeAssistant setup for a very long time. So I'm a bit disconnected with the latest updates, and it's a huge overhead to start everything again, get context and understand how to fix issues on this project

However, I've finally taken the task to set up my server at home again, so I'll probably use this project for my own use again soon.

This means I may bring this project up-to-date in the next few months. No guarantees, obviously, but I may.

Best,
Flo