Input-output conformance testing based on featured transition systems

We extend the theory of input-output conformance testing to the setting of software product lines. In particular, we allow for input-output featured transition systems to be used as the basis for generating test suites and test cases. We introduce refinement operators both at the level of models and at the level of test suites that allow for projecting them into a specific product configuration (or a product sub-line). We show that the two sorts of refinement are consistent and lead to the same set of test-cases