Context: Mutation testing has been mainly analyzed regarding traditional mutation operators involving structured programming constructs common in mainstream languages, but mutations at the class level have not been assessed to the same extent. This fact is noteworthy in the case of C + + , despite being one of the most relevant languages including object-oriented features. Objective: This paper provides a complete evaluation of class operators for the C + + programming language. MuCPP, a new system devoted to the application of mutation testing to this language, was developed to this end. This mutation system implements class mutation operators in a robust way, dealing with the inherent complexity of the language. Method:MuCPP generates the mutants by traversing the abstract syntax tree of each translation unit with the Clang API, and stores mutants as branches in the Git version control system. The tool is able to detect duplicate mutants, avoid system headers, and drive the compilation process. Then, MuCPP is used to conduct experiments with several open-source C + + programs. Results: The improvement rules listed in this paper to reduce unproductive class mutants have a significant impact in the computational cost of the technique. We also calculate the quantity and distribution of mutants generated with class operators, which generate far fewer mutants than their traditional counterparts. Conclusions: We show that the tests accompanying these programs cannot detect faults related to particular object-oriented features of C + + . In order to increase the mutation score, we create new test scenarios to kill the surviving class mutants for all the applications. The results confirm that, while traditional mutation operators are still needed, class operators can complement them and help testers further improve the test suite.

Summary: Mutation testing is a successful testing technique based on fault injection. However, it can be very costly, and several cost‐reduction techniques for reducing the number of mutants have been proposed in the literature. Cost reduction can be aided by an analysis of mutation operators, but this requires the definition of specialized metrics. Several metrics have been proposed before, although their effectiveness and relative merits are not easy to assess. A step ahead in the evaluation of mutation‐reduction techniques would be a better metric to determine objectively the quality of a set of mutants with respect to a given test suite. This work introduces such a metric, which is naturally extended to mutation operators and may be used to reduce the number of mutants, particularly of equivalent mutants. Finally, a firm mutation analysis tool for WS‐BPEL service compositions is presented, and experimental results obtained by comparing different metrics on several compositions are presented. Copyright © 2014 John Wiley & Sons, Ltd.

Business processes based in WS-BPEL compositions are rapidly becoming commonplace in recent years, so it is important to pay special attention to testing in this context. Mutation testing is a white-box testing technique that has been applied successfully to programs written in several languages. In order to apply it we need a system for mutant generation. This paper presents the first results of applying a new system, GAmera, for automatic mutant generation for WS-BPEL compositions. It is composed by three different elements: an analyzer, a mutant generator and a system that executes and evaluates the mutants. GAmera is based in genetic algorithms and attempts to minimize the number of generated mutants, independently of the number and type of mutation operators, without losing relevant information. It can also detect potentially equivalent mutants allowing to improve the quality of the test suite.