Research On Test Cases Generation Method For Changing Running Direction Function Of Train Control Center Based On UML

With the increasing electronization of railway signal equipments, the equipments taking computers as core become main safety-critical equipments, becoming the assurance ensuring the safety of running train. The Train Control Center (TCC) is an important part of Chinese Train Control System, which is strictly demanding in safety, reliability and real-time. The testing of TCC software is a critical task before putting it into use. Changing running direction in sections is an important function of TCC, therefore, researching on the method of testing this function can promote testing TCC, promoting the formation of testing theory and method with the development of advanced test platform.On the basis of analyzing TCC technical specification of changing running direction in sections, the UML statechart diagrams were built in a hierarchical structure, test paths were generated automatically and method of generating inputs and outputs of test cases were obtained. Firstly, the three-tier hierarchical models were established, including logical scene model, logical association model and inputs and outputs interface model. Secondly, the logical scene model was translated to directed graph and test requirements were generated basing on edge coverage test criterion. The spanning tree was generated searching directed diagrams, basing on Breadth-First-Search. The complete paths were used in extending the paths obtained from the directed graph, and then the complete test paths were generated for the logical scene model. Thirdly, the logical expression was obtained from every transition of every test path from the logical scene model, decomposing every variable module of the logical association model layer by layer until all the input modules were searched out, thus the combining inputs of the transition were obtained. Then the combining inputs drove the logical association modules transit their states until the state of logical scene model transits as intended and the outputs of the models were obtained at the same time. Finally, the inputs and outputs of test cases were generated from transitions on the paths.Aiming at the function model of changing running direction in sections, UML state machine model was established, test paths and the inputs and outputs of test cases were generated automatically. Therefore, the main method in this paper is to establish UML state machine model on the basis of specification, and then generating test paths and inputs and outputs of test cases automatically. This research can lay foundation of generating test cases ad test scripts, establishing the automated test platform, which is important for implementing testing TCC automatically.