ReqCap: Hierarchical Requirements Modeling and Test Generation for Industrial Control Systems

This paper presents ReqCap, an implementation of a new method that articulates hierarchical requirements modeling and test generation to assist in the process of capturing requirements for PLC-based control systems. ReqCap is based on a semi-formal graphical model that supports hierarchical modeling, thus enabling compositional specifications. The tool supports automated generation of test cases according to different coverage criteria. It can also import requirements directly from ReqIF files and automatically generate Sequential Function Charts (SFCs).We use a real-world case study to show how ReqCap can be used to model realistic system requirements. We show how the automated generation of SFCs and test cases can support engineers (and clients) in visualizing and reviewing requirements. Moreover, all the tests listed in the original test document of the case study are also generated automatically by ReqCap, demonstrating that the tool can be used to effectively capture requirements and generate valid and useful test cases.