Empirical studies of predicate-based software testing

We report the results of three empirical studies of fault detection and stability performance of the predicate-based BOR (Boolean OperatoR) testing strategy. BOR testing is used to develop test cases based on formal software specification, or based on the implementation code. We evaluated the BOR strategy with respect to some other strategies by using Boolean expressions and actual software. We applied it to software specification cause-effect graphs of a safety-related real-time control system, and to a set of N-version programs. We found that BOR testing is very effective at detecting faults in predicates, and that BOR-based approach has consistently better fault detection performance than branch testing, thorough (but informal) functional testing, simple statebased testing, and random testing. Our results indicate that BOR test selection strategy is practical and effective for detection of faulty predicates, and is suitable for generation of safety-sensitive test-cases.