Concolic Metamorphic Debugging

Debugging is challenging and labor-intensive. Debugging programs with weak or no oracle is even more difficult due to lack of passing and failing test runs as well as their comparisons. To address these challenges, we exploit metamorphic relations to construct new programs that are enhanced with synthesized oracle, and combine concolic testing and branch-switching debugging to localize potentially faulty places in original programs. We name our approach concolic metamorphic debugging (or Comedy for short). We experimentally evaluated Comedy with real-world Java programs. The experimental results reported that Comedy successfully generated debugging report for 88.4% of 2,330 faulty programs. The average branch distance between the reported locations and the real fault places is only 1.68. Besides, 36% of the debugging reports precisely locate the fault.