I was asked to crack a program in a job interview
Real-life tests are THE best thing to send job candidates. It scales well (you don't have to spend personal hours on them) and you get real information.This applies even to sysadmins. We have a favourite: set up a VM with a slightly-broken application in a slightly-broken Apache and Tomcat, and get them to ssh in and document the process of fixing it. Even people who aren't a full bottle on Tomcat will give useful information, because we get an insight into their thought processes. I recommend this to all.(I note we've just done a round of interviews where we get a nice-looking CV and conduct a technical grilling. Hideous waste of time for everyone involved. All CVs should be regarded, on the balance of probabilities, as works of fiction. Do a remote self-paced test like this. You won't regret it.)