Modeling software for accurate data flow representation

A particular model used for data flow oriented structural testing is the def-use graph which captures intraprocedural data flow dependencies within the control flow exhibited by a program written in a procedural language. Since procedures in a program are closely interrelated, data flow oriented structural testing must also be performed at the program level utilizing the interprocedural data flow dependencies. The authors point out that the accuracy of the representation of data flow dependencies by the def-use graph is no longer acceptable at the program level where the accurate representation of interprocedural data flow dependencies is needed. This point is illustrated by an error that cannot be revealed by existing data flow oriented test path selection criteria when the procedures of a program are considered individually, but can be revealed by at least two of the criteria which require accurate representation of interprocedural data flow dependencies. A new model, called the extended def-use graph is proposed to represent both intraprocedural and interprocedural data flow dependencies in the control flow exhibited by a program. This model facilitates the application of the existing data flow oriented test path selection criteria at the program level. >