Black-box testing tool of railway signalling system software with a focus on user convenience

摘要

A railway signalling system is the control equipment performing vital functions, and the validation on functional safety of its software is a very important issue. Recently, various software testing tools have been applied to verify signalling system software. However, these tools are unable to support black-box testing to verify the functional safety of embedded signalling system software, and few black-box testing tools are currently commercialized. Since most of these commercialized black-box testing tools depend on a testing method through direct accessing to the target memory under test, there are a lot of difficulties when applying them to the test. In the case of using the existing tool, it is possible to test them only if the internal memory addresses values that are occupied by the executing embedded software. Therefore they are rarely utilized to verify the embedded software in the actual operating environment. To overcome these problems, this study developed a black-box testing tool using communication interfaces which are utilized when actually operating. The real interface channel is used as an input and monitoring channel for black-box testing. This approach carries out the test in a manner where the test data are input and the results are fed back to these interface channels by utilizing interface channels with other signalling equipment already operating. Boundary value analysis and equivalence class analysis modules were used to generate test cases within the developed new testing tool. The pilot of the proposed testing tool has been completed, and the feasibility study is now in progress with railway signalling system software in Korea as its test target.