Theoretical Analysis and Empirical Study on the Impact of Coincidental Correct Test Cases in Multiple Fault Localization

To improve the efficiency of the fault localization process, different automatic fault localization approaches have been proposed. Among these approaches, the spectrum-based fault localization (SBFL) approach has been widely used and studied due to its lightweight and high effectiveness. However, while the existence of coincidental correct (CC) test cases can influence the usefulness of SBFL in single-fault programs, their influence on multiple fault programs has not been thoroughly investigated. Therefore, in this article, we conduct a theoretical analysis and an empirical study to investigate the effect of CC test cases on multiple fault localization. The theoretical analysis is based on a suspiciousness calculation formula of SBFL, which divides CC test cases into three categories (specific, irrelevant, and unspecific) according to their association with a specific faulty statement. Following this analysis, we conduct an empirical study on two well-known open-source repositories (SIR and Defects4J), and the experimental results verify the correctness of our theoretical analysis. Specifically, reducing the number of specific CC test cases for a faulty statement can improve or maintain fault localization accuracy, while eliminating irrelevant CC test cases can have a negative effect. Finally, we design a CC test case identification solution based on the isolation-based multiple fault localization approach and demonstrate its effectiveness via a simulation experiment.