Specification-based testing for software product lines

In this paper, we develop a testing theory for specification-based software product line development. Starting with a framework for the evaluation of test cases with respect to formal specifications, we develop a notion of enhancement, which allows to re-use test cases in a horizontal systems development process. In such a process, more and more features are added to an existing software product. For specification-based testing, this means that the corresponding specifications are enhanced more and more, and that new test cases must be added to an existing test suite in order to test the additional features. We formally define an enhancement relation between CSP-CASL specifications, describe a test evaluation method for software product lines based on CSP-CASL specifications, and prove several preservation results which allow to re-use test cases in a horizontal development. We illustrate our approach with the example of a product line of remote control units for consum er products.