Realisticly the problem here is;
The headline says they're generating unit tests automatically.
Which means I expect that I run a command, and it plops out unit test code. automatically. without my interaction.
The article is about recording repl interactions. that's not automatic.
and really, they look like implementation details? so bad examples? I don't know scheme, so shrug
Your problem appears to be your entire focus is pointlessly nitpicking the meaning of everyone’s words where enough context exists to trivially disambiguate it.
You gotta pick a better hobby.
You said a unit test is 'what' you test?
So if I say 'I wrote a unit test' what kind of test do you expect?
1. Unit testing is a kind of functional testing. On a unit.
2. And regression testing is rerunning your existing functional tests after, say, refactoring, to see if they pass.
Complex? Confusing? Which part of this precisely is confusing?