I wouldn't expect somebody doing a small (15 min) program do it with TDD. If they will do it - it will be a plus, but it's not that important.
BTW: What is your position versus the person you interview? (Are you on the same table looking at the same monitor or are you behind him looking at the code?)
BTW: What is your position versus the person you interview? (Are you on the same table looking at the same monitor or are you behind him looking at the code?)