Research And Implementation Of Model-Based Full Coverage Testing Method For Safety Critical Software

The computer software quality problem is always an important and difficult issue in the software development process. The software plays a very important role in many modern systems, such as aviation industry control systems, railway signaling systems, nuclear power plants and medical equipments. As the embedded system software becomes more and more important, the RTCA developed DO-178B as airborne software development guideline, CENELEC defined EN 50128 as signaling software development guideline, both standards provide detailed instructions and regulation for software testing process and especially figure out the coverage issue. Above two standards explain that the purpose of the structural coverage analysis is to complement the requirements-based testing, it can find the unintended functions. As the increasing demand of complexity and performance for embedded system design, people are more and more dependent on coverage measures for the testing process, to ensure the efficiency and completeness of verification.The structural coverage includes several modes like statements coverage, decision coverage, MC/DC coverage. We make a detailed explanation and comparison of these modes in this paper, and point out the huge advantage in MC/DC application effect. Then MC/DC concepts are specifically introduced, and we analyze the advantages of MC/DC design method (the Unique-cause method and Masking method), while we expound several typical evaluation analysis strategies of the MC/DC.In this paper, we propose the idea that using model coverage instead of code coverage, and then use SCADE Suite as a platform and Automatic Train Protection Mode Transition software as an example to explain the whole process of analyzing model coverage deeply.