Using symbolic execution to aid automatic test data generation

It is shown how symbolic execution is used to solve the internal variable problem in the Godzilla test data generator. In constraint-based testing, which is used by the system, the internal variable problem appears when the constraints that specify the test cases contain internal variables. The necessary background is developed by describing the constraint systems used by Godzilla and by discussing symbolic execution in general terms. The application of symbolic execution to the internal variable problem is presented. The discussion focuses on the software used, including algorithmic details. Following this, a practical example of using this system to detect a fault in a small program is presented.<>