Designing deletion mutation operators

Abstract

Mutation analysis modifies a program by applying syntactic rules, called mutation operators, systematically to create many versions of the program (mutants) that differ in small ways. Testers then design tests to cause the mutants to behave differently from the original program. Mutation testing is widely considered to result in very effective tests, however, it is also quite costly. Cost comes from the many mutants that are created, the number of tests that are needed to kill the mutants, and the difficulty of deciding whether mutants behave equivalently to the original program. One-op mutation theorizes that cost can be reduced by using a single, very powerful, mutation operator that leads to tests that are almost as effective as if all operators are used. Previous research proposed the statement deletion operator (SDL) and found promising results. This paper investigates the use of SDL-mutation in a new context, the language C, and poses additional empirical questions, including whether other operators can be used. We carried out a controlled experiment in which cost and effectiveness of each individual C mutation operator were collected for 39 different subject programs. Experimental data are used to define a cost-effectiveness metric to choose the best single operator for one-op mutation.