[slifin]

I suppose interviewers regularly fail people for less than this but it's just ridiculous I bet if the interviewee is told to add unit tests the majority could and would

It's not a test of skill so much as a test of expectation, hidden expectations are the worse to deal with in an interview

If we're going to wag the testing finger and say always unit tests then why not always generative tests? They'd always test more inputs, why not spin those tests infinitely? Did they test in the repl? why not always mutation testing? why not always integration testing?

I don't think people like to realise that testing is a spectrum of confidence you'll never reach 100% nor should you expect to

Dealing in bullshit absolutes here is stupid, talk to your interviewee about what they could do to ensure their code complies with its intent instead of springing hidden expectations after the fact