Towards a more efficient way of generating test cases: class graphs

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. One of these systematic approaches is deriving test cases from a classification tree. This approach partitions the input domain into classifications. Classifications are further partitioned into classes. Test cases are combinations of classes. Relations between classifications and classes are identified and are used to construct the classification tree. From the classification tree, a 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 valid. This problem is incurred by the limitation of the expressive power and elegance of the two kinds of relations, namely classification classes and Class-Classification, that are allowed in the classification tree. We propose an enhancement of the classification tree by replacing the two kinds of relations by a Class-Class relation. We call this new approach Class Graphs. This paper describes the class graphs approach and compares its expressive power with the classification tree and show how test cases can be derived from class graph in a more efficient way.