MuTMuT: Efficient Exploration for Mutation Testing of Multithreaded Code

Mutation testing is a method for measuring the quality of test suites. Given a system under test and a test suite, mutations are systematically inserted into the system, and the test suite is executed to determine which mutants it detects. A major cost of mutation testing is the time required to execute the test suite on all the mutants. This cost is even greater when the system under test is multithreaded: not only are test cases from the test suite executed on many mutants, but also each test case is executed for multiple possible thread schedules. We introduce a general framework that can reduce the time for mutation testing of multithreaded code. We present four techniques within the general framework and implement two of them in a tool called MuTMuT. We evaluate MuTMuT on eight multithreaded programs. The results show that MuTMuT reduces the time for mutation testing, substantially over a straightforward mutant execution and up to 77% with the advanced technique over the basic technique.