The production of such tests presumably requires an element of human reasoning.

The requirements have to come from somewhere, after all.

I would argue that designing and implementing a working project requires human reasoning, too, but that line of thinking seems to be falling out of fashion in favor of "best next token" guessing engines.

I know what Spock would say about this approach, and I'm with him.

"Beware of bugs in the above code; I have only proved it correct, not tried it."

Donald E. Knuth

Human reason is fine, the problem is that human attention spans aren't great at checking for correctness. I want every corner case regression tested automatically because there's always going to be some weird configuration that a human's going to forget to regression test.

With any non trivial system you can’t actually test every corner case. You depend on human reason to identify the ones most likely to cause problems.

Both are necessary, they complement each other.