Test generation approach based on Colored Petri Net of Mode Transition in on-board subsystem

Testing of the on-board subsystem is a vital factor to assure the functionality and safety of a railway signal system. With the increase in size and complexity of mode transition on on-board equipment, the difficulties in fewer test sequences of mode transition which achieve complete coverage of transition paths are aggravated. In this paper we present a Colored Petri Net (CPN) model-driven test generation method of mode transition. Firstly, the system's mode transition model based on CPN (Mode Transition CPN, MTCPN) is designed on the basis of the mode transition specification of on-board subsystem. Secondly, in order to avoid state space explosion and endless loop of the MTCPN model, test target sequences of mode transition based on the Chinese Postman Algorithm are generated to drive simulation execution of the MTCPN model. Finally, the fewer executable test sequences and their Extensible Markup Language (XML) instances are obtained to achieve complete coverage of mode transition paths and corresponding coverage criterions of CPN.