The application of an algebraic design method to deal with oracle problem in object-oriented class level testing

In order to ensure reliability and quality, software systems must be tested. The testing includes generating test cases, executing test cases on the program, and determining whether the results of execution conform to requirements. The last is called the oracle problem. The oracle problem is important but difficult as the program yields the results in a way which may depend on some representation choices and makes the comparison with the specified results difficult. The class level testing is considered to be basic in object-oriented software testing. Breu et al. (1998) proposed an algebraic design methodology for object-based systems. We found that this design methodology can be used to deal with the oracle problem in object-oriented class level testing. Given an algebraic specification for a class, suppose the equivalent ground terms u₁~u₂ are selected as a test case. Using the representation function rep() provided by Breu´s algebraic design methodology, u₁ and u₂ can be mapped to method sequences s₁ and s₂ in the implementation, respectively. Executing s₁ and s₂ in the implementation, we obtain accordingly two objects O₁ and O ₂ of the given class