It's the kind of testing my colleague would do. "well, nobody would be idiotic enough to enter something weird when they are asked for a number". And so he'd only write tests for numbers. That kind of stuff.
The unit tests I'm looking at in this latest jobs are some primo "dev testing" bullshit. Their sole purpose clearly was to be able to say "we unit test our code in our pipeline and it all passed" and that's about it. Ugh.

As per xkcd, dev testing would return the response "could not reproduce"

Gotta make sure the code runs.