Putting your best tests forward

Test case prioritization orders tests so that they help you meet your testing goals earlier during regression testing. Prioritization techniques can, for example, order tests to achieve coverage at the fastest rate possible, exercise features in order of expected frequency of use, or reveal faults as early as possible. We focus on the last goal, which we describe as "increasing a test suite's rate of fault detection" or the speed with which the test suite reveals faults. A faster fault detection rate during regression testing provides earlier feedback on a system under test, supporting earlier strategic decisions about release schedules and letting engineers begin debugging sooner. Also, if testing time is limited or unexpectedly reduced, prioritization increases the chance that testing resources will have been spent as cost effectively as possible in the available time.