Prioritizing tests for software fault diagnosis

During regression testing, test prioritization techniques select test cases that maximize the confidence on the correctness of the system when the resources for quality assurance (QA) are limited. In the event of a test failing, the fault at the root of the failure has to be localized, adding an extra debugging cost that has to be taken into account as well. However, test suites that are prioritized for failure detection can reduce the amount of useful information for fault localization. This deteriorates the quality of the diagnosis provided, making the subsequent debugging phase more expensive, and defeating the purpose of the test cost minimization. In this paper we introduce a new test case prioritization approach that maximizes the improvement of the diagnostic information per test. Our approach minimizes the loss of diagnostic quality in the prioritized test suite. When considering QA cost as a combination of testing cost and debugging cost, on our benchmark set, the results of our test case prioritization approach show reductions of up to 60% of the overall combined cost of testing and debugging, compared with the next best technique. Copyright (C) 2011 John Wiley & Sons, Ltd.