Disclosed is a method for using source code to create the models used in model-based testing. After exploring the intended behavior of a software package, a test engineer writes source code to model that intended behavior. The source code is compiled into a model, and the model is automatically analyzed to generate numerous test scripts that can exercise the behavior of the software package. When the tests are run, their results are compared against intended behaviors, and discrepancies are used to correct the software package (or to correct the source-code model if it was prepared incorrectly). The model coding, test generation, test execution, and comparison steps are repeated as often as necessary to thoroughly test the software package. In some embodiments, the test scripts generated by the model are written in XML (Extensible Markup Language), allowing the easy integration of the test scripts with a number of XML-based tools.