In interviews I usually just ask developers to show me some code (any code) and ask them random questions about it. I’ll ask them what libraries they use and why, or why they wrote some piece of code the way it is, or why did they or didn’t test certain pieces of code.

Their answer will usually show their (reasoning) skill and whether they care. Talking and reasoning about code is an important skill for a developer for me, so that’s what I’ll focus the interview on.

I don’t care whether the library is a good or bad choice. I don’t care about the code itself or whether it’s good or bad. I just want to know if they can tell me why it is the way it is.