[asgraham]

If you can write tests fast enough, you can specify those business rules on the fly. The ideal case is that tests always reflect current business rules. Usually that may be infeasible because of the speed at which those rules change, but I’ve had a similar experience of AI just getting tests right, and even better, getting tests verifiably right because the tests are so easy to read through myself. That makes it way easier to change tests rapidly.

This also is ignoring that ideally business logic is implemented as a combination of smaller, stabler components that can be independently unit tested.

[skydhash]

Unit tests value is mostly when integration and more general tests are failing. So you can filter out some sections in the culprit list (you don’t want to spend days specifying the headlights if the electric design is wrong or the car can’t start)

Having a lot of tests is great until you need to refactor them. I would rather have a few e2e for smoke testing and valuable workflows, Integration tests for business rules. And unit tests when it actually matters. As long as I can change implementation details without touching the tests that much.

Code is a liability. Unless you don’t have to deal with (assembly and compilers) reducing the amount of code is a good strategy.