Special issue on mutation testing and analysis

Program mutation is acknowledged as an important method to assess the fault-finding capabilities of an existing test suite (mutation analysis) and to generate efficient and effective test suites (mutation testing). Mutation has mostly been applied at the source code level, but more recently, related ideas have also been used to test artefacts described in a considerable variety of notations and at different levels of abstraction. Ideas derived from mutation testing are used with requirements, formal specifications, models, architectural design notations, and informal descriptions. Data mutation has also been investigated for critical systems, embedded systems, and web services. Mutation is thus an established method in verification and validation of software and hardware systems. This special issue covers a wide variety of research areas connected to program mutation, mutation analysis, and mutation testing. Specifically, it covers theoretical analyses over mutant subsumption, cost reduction with mutant clustering, new mutation operators for feature-oriented software product lines, and applications of mutation analysis to prioritize tests, evaluate model clone detectors, and generate tests for regular expressions. This special issue includes three extended manuscripts, previously presented at the International Workshop on Mutation Analysis in years 2016 and 2017. Since 2009, the mutation analysis workshop has been an annual event where researchers and practitioners meet to discuss new and emerging trends in mutation analysis, and so far, there have been 14 total occurrences of the workshop. The guest editors would like to thank all the authors of this special issue for their contributions and the reviewers for devoting their time. We hope the reader will enjoy this special issue.