I look for test data.  Up front.  Particularly from developers with 3+ years of experience.<p>It demonstrates you understand the problem and are thinking about the cases that you will have to solve.  It also acts as a good safety net for your implementation.<p>If you&#x27;ve got test data that will catch a bug, I won&#x27;t count it against you in your implementation.  However, if you&#x27;ve got a buggy implementation and you haven&#x27;t provided test data for it, then it&#x27;s broken.