On the “semi-functions” name: my points were to make it a short single word, just because they are referenced a lot in the post itself and I didn’t want to make the post very wordy. I considered “semi-function” and “run-function”.

On testability: right, I missed this aspect. Vladimir Sitnikov pointed to the same thing. I think it should be a part of the “tooling support” to be able to call semi-functions from tests.