If you write a unit test for each branch in your method and just put in the current behavior as the expectation, all you've done is created a test that says "the method does what it currently does."
It isn't that stupid, and that was done at least a decade ago with static+control flow analysis. As for AI, I was recently writing tests for a VT push parser in Rust (which is novel code, so no parroting here) and it clearly knew enough about VT to write a, correctly, failing test. I had a bug in my parser, and the test that AI generated found it.
At the end of the day, I'm not sure why anyone would believe the critique of someone who hasn't used a tool in earnest.
It isn't that stupid, and that was done at least a decade ago with static+control flow analysis. As for AI, I was recently writing tests for a VT push parser in Rust (which is novel code, so no parroting here) and it clearly knew enough about VT to write a, correctly, failing test. I had a bug in my parser, and the test that AI generated found it.
At the end of the day, I'm not sure why anyone would believe the critique of someone who hasn't used a tool in earnest.