TCE+: An Extension of the TCE Method for Detecting Equivalent Mutants in Java Programs

While mutation testing is considered to be an effective technique in software testing, there are some impediments to its widespread use in industrial projects. One of these challenges is the equivalent mutant problem, and a line of research is dedicated to proposing new methods for addressing this problem. Trivial Compiler Equivalence (TCE) method is recently introduced as a simple technique that actually relies only on the optimizations made by the compiler. It is shown by empirical studies that employing TCE with the gcc compiler results in a fast and effective technique for detecting equivalent mutants in C programs. However, considering the fact that the Java compilers generally do not perform noticeable optimizations, the question is how effectively does TCE perform on Java programs? In this paper, experimental evaluations are discussed which demonstrate that using TCE technique with javac compiler results in very poor performance. As a result, this paper proposes to use the Java obfuscators as the complementary component, because of the optimizations they make. The experimental evaluations confirm that using TCE with the ProGuard obfuscation tool provides an effective and efficient method for detecting equivalent mutants in Java programs.