Automated Test Case Generation for Safety-Critical Software in Scade

Software systems for automating safety-critical tasks in application domains like, for example, avionics, railways, automotive, industry 4.0 and healthcare, must be highly reliable. In this paper, we focus on safety-critical software written in Scade, a model-based programming language largely adopted in industry, and we specifically draw on our own experience in a joint industry-university project aimed at developing safety-critical Scade programs for the railways domain. We investigate automated test case generation for Scade programs. We leverage on state-of-the-art test generators based on either symbolic execution, bounded model checking or search-based testing, in order to define an original toolchain for generating test cases for Scade programs. We rely on the toolchain to explore the absolute and relative effectiveness of those mainstream test generation approaches on a benchmark of 37 Scade programs developed as part of an on-board signaling unit for high-speed railway systems.