[MSDN] This month I’ll begin with the role of combinations in software testing. The ability to programmatically generate combinations gives you a powerful way to generate test case input. To see what I mean about combinations, suppose you are writing a poker program. Manually generating all possible five-card test inputs would not be pleasant. But with the code in this column you can do it in minutes…

Dr. James McCaffrey has a great look at using combinatorial test cases. From personal experience, I’ve found that using pairwise combinations is an extremely efficient way to cover a large amount inputs when developing test cases. Pairwise Testing is also a good read on the subject.