>Some may think no CS graduate would fail a test that let you choose any popular language to implement some basic string parsing.
I don't see anything wrong with basic screeners like that, but I have experienced some really silly stuff. Recently I was given a test that asked ~10 questions (some trivia, some paragraph type response), a few small simple questions (reverse a string, etc.), create a class to handle card games (poker, blackjack, etc.), and create a user repository... in 30 minutes. I felt like a dog at a dog show.