Impacts of test suite's class imbalance on spectrum-based fault localization techniques

Spectrum-based fault localization (SBFL) uses the execution results of test cases to debug. There are two types of SBFL techniques: one using conventional slices, and the other using metamorphic slices. This paper investigates the ratio between non-violated and violated metamorphic test groups of test suites for SBFL techniques using metamorphic slices. We have observed that the higher the ratio of passed metamorphic test groups to failed metamorphic test groups, the less effective the SBFL techniques using metamorphic slices. This observation is consistent with what has been observed in SBFL techniques using conventional slices. Besides, a new real-life fault in schedule2 of Siemens Suite is identified in our experiments.