Software Input Space Modeling with Constraints among Parameters

This paper considers the task of software test case generation from a large space of values of input parameters. The purpose of the paper is to create a model of software input space with constraints among parameters to serve as a basis of testing. We suggest a procedure to create a directed graph model, where paths through the graph represent all valid (and only valid) input combinations. The procedure accommodates an arbitrary set of dependencies among parameters. It starts from a simple linear graph and sequentially modifies this graph for each dependency between parameters. Modifications include subgraph splitting and elimination of dead nodes and edges. A complete example of a system with six input parameters and five dependencies among them is presented to illustrate the application of the procedure. Applicability of the approach for different types of parameters and dependencies is addressed.