Using coverage information to predict the cost-effectiveness of regression testing strategies

Selective regression testing strategies attempt to choose an appropriate subset of test cases from among a previously run test suite for a software system, based on information about the changes made to the system to create new versions. Although there has been a significant amount of research in recent years on the design of such strategies, there has been very little investigation of their cost-effectiveness. The paper presents some computationally efficient predictors of the cost-effectiveness of the two main classes of selective regression testing approaches. These predictors are computed from data about the coverage relationship between the system under test and its test suite. The paper then describes case studies in which these predictors were used to predict the cost-effectiveness of applying two different regression testing strategies to two software systems. In one case study, the TESTTUBE method selected an average of 88.1 percent of the available test cases in each version, while the predictor predicted that 87.3 percent of the test cases would be selected on average.