Extreme configurability of the platform I’m working on for my dayjob has sparked my interest in Pairwise Testing.

Pairwise.org defines this testing method in a short, concise way:

Pairwise (a.k.a. all-pairs) testing is an effective test case generation technique that is based on the observation that most faults are caused by interactions of at most two factors. Pairwise-generated test suites cover all combinations of two therefore are much smaller than exhaustive ones yet still very effective in finding defects.

Developer.* has a great introduction to the technique in the article “Test Smarter, Not Harder”.