Uml based test cases generation for the centralised control system of high speed maglev

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Background: The high speed maglev centralized control subsystem (CCS), which realizes the display, automatic train operation (ATO) and diagnose. The CCS is an important security assurance for train operation. System testing (ST) can detect design defects early and performed effective repair to improve the efficiency of the system’ on-site coordinated operation. Therefore, the quality of test cases directly determines the achievements and efficiency of CCS, and it is necessary to be tested before put it into use.
 Aim: The generation of test case of centralized control subsystem is proposed.
 Methods: In order to meet the requirements of the system, the first step is operating the extraction of functional features. Then, the unified modeling language is using to develop the test model in this paper. Then the corresponding unified modeling language models, use case diagram, state diagram, activity diagram and sequence diagram, are developed. The state diagram of operation process is using to describe the state transition during the period from initial state of the OTS to the completion of the operation. The activity diagram of train operation process focuses on the control relationship during the period from one activity to another, which can describe the interaction exactly between OTS, DCS and VCS. The sequence diagram, behavior of use case, focuses on the sequence of information sent by objectives, in which a group of objectives and information transfer are presented. And according to these models, the test cases of the specified case are generated.
 Results: The generated test cases are all executed in the developed lab-test system. The results show that the generated test cases can fully simulate the common situations of the operation scene, and effectively improve the test efficiency and test quality. We designed the experiments as followings: 85 test cases for terminal system design of operator, 68 test cases for train automatic operation design, 31 test cases for central diagnostic system design. All of the designed test cases are examined through the test platform, covering all main scenes in operation process. The errors or detects found in tests are solved by finding the reasons and modifying the code, etc. Finally, the pass rate of the method proposed in this paper is 100 %. 
 Conclusion: The UML based method of test case generation implements the generation process and achieves the test cases and verification for CCS. Through the test practice, test cases designed can fully simulate all kinds of common situations in the operation site. What’s more, the test cases also realize early detection of errors and defects in the system and repair them. It is useful to improve the efficiency on-site testing process, to reduce the cost of time and test quality. The method can provide theoretical basis and reference for further testing of high speed maglev CCS.