This cannot be done because I cannot use AkkaSpec (or TestKit) because it would imply to create another actor system implicitly and I'd like to test the failure of actor system creation. I'm afraid this is not the right design of TestKit where within() and awaitAssert should not depend on the presence of an actor system. But factoring out this functionality is out of scope, imho.

Do you agree?

I'll perform the other fixes and consolidate the commits into one.