An Empirical Evaluation of the MuJava Mutation Operators

Mutation testing is used to assess the fault-finding effectiveness of a test suite. Information provided by mutation testing can also be used to guide the creation of additional valuable tests and/or to reveal faults in the implementation code. However, concerns about the time efficiency of mutation testing may prohibit its widespread, practical use. We conducted an empirical study using the MuClipse automated mutation testing plug-in for Eclipse on the back end of a small web-based application. The first objective of our study was to categorize the behavior of the mutants generated by selected mutation operators during successive attempts to kill the mutants. The results of this categorization can be used to inform developers in their mutant operator selection to improve the efficiency and effectiveness of their mutation testing. The second outcome of our study identified patterns in the implementation code that remained untested after attempting to kill all mutants.