Using non-redundant mutation operators and test suite prioritization to achieve efficient and scalable mutation analysis

Mutation analysis is a powerful and unbiased technique to assess the quality of input values and test oracles. However, its application domain is still limited due to the fact that it is a time consuming and computationally expensive method, especially when used with large and complex software systems. Addressing these challenges, this paper makes several contributions to significantly improve the efficiency of mutation analysis. First, it investigates the decrease in generated mutants by applying a reduced, yet sufficient, set of mutants for replacing conditional (COR) and relational (ROR) operators. The analysis of ten real-world applications, with 400,000 lines of code and more than 550,000 generated mutants in total, reveals a reduction in the number of mutants created of up to 37% and more than 25% on average. Yet, since the isolated use of non-redundant mutation operators does not ensure that mutation analysis is efficient and scalable, this paper also presents and experimentally evaluates an optimized workflow that exploits the redundancies and runtime differences of test cases to reorder and split the corresponding test suite. Using the same ten open-source applications, an empirical study convincingly demonstrates that the combination of non- redundant operators and prioritization leveraging information about the runtime and mutation coverage of tests reduces the total cost of mutation analysis further by as much as 65%.