Pairwise (a.k.a. all-pairs) testing is a test case generation technique that is based on Microsoft's 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.

I have taken the pairwise approach and applied it during an entire release cycle of Red Hat Enterprise Linux. I've made an experiment where I have reduced the test matrix for 9 product variants and 4 CPU architectures to a size suitable for execution by a single person. In this talk I will explain: - what is the background of the product and how it was traditionally tested - how I've constructed my experiment - how many test cases I was able to remove from the test matrix - how the results and risk level compare to the standard exhaustive test suite!

I will also talk about bugs found and bugs missed by the two approaches.