Generating test cases from class vectors

Specifications are the primary source for obtaining test cases in software testing. Specification based testing is becoming more and more important when black box components and COTS are widely used in software development. An important issue in system testing is to identify all the legitimate input. One of these systematic approaches is deriving test cases from classification tree. This approach partitions the input domain into classifications which are further partitioned into classes. Test cases are combinations of classes. Relations between classification and classes are identified and are used to construct the classification tree. From the classification tree, combination table is constructed. Test cases are derived from the combination table. However, human decisions are required in determining whether test cases derived from the combination table are legitimate. This problem is incurred by the limitation of the expressive power of classification trees which cannot express the relations among classes precisely. We propose an enhancement by expressing the relations among classes and the relations among classifications directly in vectors. We call this new approach Class Vectors. This paper presents the class vector approach with formal definitions of basic concepts and entities. We find that the expressive power of class vectors is higher than classification trees, that is, this approach can express the information given in the specification in a better way and derive all legitimate test cases with minimal human decisions. Furthermore, a method of generating legitimate test cases using class vectors is described. This method is derived from the formal semantics of class vector, hence it is theoretical sound. Finally, we discussed that the proposed method requires the least amount of human decisions, can be highly automatic and has good usability.