[fwlr]

I partially agree - I would say more specifically “those situations are the easiest to write good tests for”, ie having a predefined spec will strongly guide you towards writing good and useful tests.

“Testing that the code does what it does” is of course a terrible waste of both the time spent writing those tests, and of future time spent writing code under those tests. With skill and practice at writing tests, you make that mistake less often. Perhaps there’s a bit of a self-fulfilling prophecy for game developers: due to industry convention, they’re unfamiliar with writing tests, they try writing tests, they end up with a superfluous-yet-restrictive test suite, thus proving the wisdom of the industry convention against testing.