... BTW, it's very similar to mocks implementations. The 1-st version was (as in SMocks) something like:

mock expect: #messageSend.
...
self checkExpectations.

But it's much more intension-revealing and convinient to use mocks another way (as in Mocketry for example):

[sut doSomethings] checking: [mock messageSend].

I think in the case of example-driving tests it's still actual...

--
Dennis Schetinin