FTScMES: A New Mutation Execution Strategy Based on Failed Tests' Mutation Score for Fault Localization

Fault localization has been one of the most expensive activity in the whole debugging process. The spectrum-based fault localization (SBFL) is the most studied and evaluated technique. Other approach is the mutation-based fault localization technique (MBFL) that needs to execute the test suite on a large amount of mutants increasing its cost. Efforts from research community have been performed in order to achieve solutions reducing such cost and keeping a minimum quality. Current mutation execution strategies are evaluated considering artificial faults. However, recent researches show that some MBFL techniques exhibit low efficacy fault localization when evaluated on real faults. In this paper, we propose a new mutation execution strategy based on failed tests’ mutation score, called (FTScMES), aiming to increase the efficacy on fault localization reducing the cost of mutants execution. FTScMES uses only the set of failed test cases to execute mutants and bases on mutation score concept to compute the suspiciousness statements. The experiments were conducted considering 221 real faults, comparing the efficacy of localization of FTScMES against 5 baselines from the literature. We found that FTScMES outperforms the baselines reducing the cost in 90% on average with a high efficacy of ranking defective code.