How about adding more specific tests? You could split CHECK_EXPECT into
actual states, so it would be like
CHECK_EXPECT(OpenStateChange_MediaChanging),
CHECK_EXPECT(PlatStateChange_Waiting) and alike.

Well, one call to something like put_url produces about 10 state
changes, some are playlist related that is functionality we are
missing.
Do we need / want to test for them all?
If we want to be as specific as possible - do we need to test for
order of those changes as well?

We don't need all of them, at least not yet. Adding ones that you implement would be nice.

Thanks,

Jacek