Research And Application Of Test Case Automatic Generation Algorithm In Onboard Automatic Train Protection

In order to guarantee the safety of train operation, improve the transportation efficiency and market competitiveness, the system strategy of CTCS (Chinese Train Control System) is proposed by railway department based on the national situations. The research on CTCS-3 is gradually performed and improved, and as a safety critical rail control system, there should be complete test for CTCS to ensure the comprehensive verification of the system, in which the functional test is the most important part for the system safety, with the aim at verifying whether the system could meet the system requirement specifications. And as the key part of train control, it is of great importance for the function test of onboard subsystem.Test is a time consuming project, and appropriate test method will improve the efficiency. The test case is the core of the whole testing process, and is also the fundamental basis of the test execution. With the development of test automation, the generation of test case has become one of the key problems. The ability of detection for errors would vary with testing data, so high efficient testing data should be selected to improve the efficiency and reduce the cost. The aim of this paper is the test method and test case automatic generation for onboard ATP (Automatic Train Protection) subsystem in CTCS-3.Firstly, starting with the traditional testing theory, the advantages and disadvantages of the existing test methods are analyzed. As the black-box and white-box test are incomplete, the hybrid test, in which the black-box and white-box approach are combined, is proposed to be an improvement, and the principle and implementing process of hybrid test are detailed described. The thoughts of hybrid test provide a basis for the design of test case.Secondly, test case automatic generation in hybrid test is researched. The pairwise covering test is an effective approach for test case automatic generation. Based on the consideration of combined covering in test, the algorithm of pairwise test case automatic generating based on the net model is mainly studied, the influence of parameter sorting is analyzed, and corresponding solutions are presented.Finally, take the onboard ATP subsystem of CTCS-3 as the object, the testing function requirements are analyzed. Based on the testing requirement of speed supervision function in onboard ATP subsystem, the hierarchical division of the testing functions is made for different operating mode. Under certain parameter selecting and sorting strategy, the test case automatic generation in different mode and hierarchy is realized by the proposed automatic generating algorithm, and also the reduction and management of the test cases. The generating result demonstrates that, with appropriate parameter selection and sorting strategy, the test case automatic generation algorithm earns a high coverage and reduction rate, and there would be important significance for the testing efficiency.