Predicate Testing Generation for Safety-critical Systems

Safety-critical systems are those systems whose failure would cause significant property loss or crisis. These systems possibly contain complex predicates, which represent the conditions of system state transformation. Predicate testing is critical to ensuring system safety. However, it is difficult to generate appropriate test cases for complex predicates. To resolve the issue, predicate testing criteria based on major clause are proposed. Major clause of predicate is a clause that directly determines the value of predicate, and the preponderances of testing criteria based on major clause is that not only guarantee the rigor of testing, but also reduce the testing cost. This paper presents an approach that using different test criteria based on major clause to automatically generate corresponding test case constraint set for predicates in safety-critical systems. Firstly, the complex predicate is modeled as an abstract syntax tree (AST). Secondly, truth table for predicates is generated by extracting AST and further filtered based on predicate testing criteria (such as PC, RACC and CACC). Finally, testing case constraints set is generated by a random algorithm to satisfy certain test criteria. Our experimental results show that the constraint set generated by our method is reasonable and our approach is correct. By introducing variants into the empirical system, our approach shows the validity of different test criteria.