I just write my own code and then ask AI to find any issues and correct them if I feel it is good advice. What AI is amazing at is writing most of my test cases. Saves me a lot of time.
To be fair, many human tests I've read do similar.
Especially when folks are trying to push % based test metrics and have types ( and thus they tests assert types where the types can't really be wrong ).
I use AI to write tests. Many of them the e2e fell into the pointless niche, but I was able to scope my API tests well enough to get very high hit rate.
The value of said API tests aren't unlimited. If I had to hand roll them, I'm not sure I would have written as many, but they test a multitude of 400, 401, 402, 403, and 404s, and the tests themselves have absolutely caught issues such as validator not mounting correctly, or the wrong error status code due to check ordering.
It's good at writing/updating tedious test cases and fixtures when you're directing it more closely. But yes, it's not as great at coming up with what to test in the first place.
The assertion here is not about implementation logic. GP presumably has in mind unit tests, specifically in a framework where the test logic is implemented with such assertions. (For the Python ecosystem, pytest is pretty much standard, and works that way.)
Majority of data in typical message-passing plumbing code are a combination of opaque IDs, nominal strings, few enums, and floats. It's mostly OK for these cases, I have found. Esp. in typed languages.