Hm... this is a bit less trivial than it sounds. I could understand a tutorial that describes what a regex should and should not match and the range of inputs and the user has to enter a regex and the program tests it against a good range of inputs to test for false-positives and false-negatives. But how do you have radio buttons to describe a range of inputs and what should match and what shouldn't match and automatically generate a good test suite? Anyone?