Combined UML-based System- and Test Models as Backbone for the Development Process

Abstract

It is common practice to (mentally) split the creation of a system into two phases: the development itself and the testing. Often, different groups of people are involved in these phases using their own tools, methods and processes. As a consequence, many tasks (like processing and tracing requirements) are done twice or more. One possible solution is to see the process as a whole with a single model for development and testing as a backbone. This approach offers a number of advantages: • Requirements are captured once and can be referred consistently through the complete model / the complete process • One single means of description throughout the process, one single homogeneous model • Seamless traceability of requirements in both horizontal and vertical direction (which means requirement -> implementation and requirement -> test case in V-shaped processes) • Development groups and testers work closer together, which can increase the product quality at decreased efforts • Many textual documents (e. g. architecture-, design- and testing descriptions) can be replaced by the model • A formal, consistent model with development and testing specifications eases validation and verification and is a powerful base for safety proofs (e. g. for approvals from authorities and assessors) In a case study, the Institute of Transportation Systems (IFS) of the German Aerospace Center (DLR) has shown the applicability of a combined development- and testing model using SysML and U2TP. For a module of the simulation laboratory RailSiTe (Rail Simulation and Testing), a joint description with SysML and U2TP was created and the above predicted advantages could be empirically proved. With scripting support, coverage examinations for requirements and test cases have been performed and the impact of requirement changes could be estimated.