Research On Test Case Generation Method Of Subway Interlocking Software Based On UML

Computer interlocking is the important technical measures to ensure the safe operation of trains, and the analysis, testing and validation of interlocking logics are the basis of meeting the requirement of harsh conditions. Interlocking software is important device to ensure driving safety, so it is essential to be tested periodically. Researching on test cases generation based on model can solve the generality problem of interlocking software testing. Unified modeling language(UML) has become the focus in the model test, which provides support for the description of complex interlocking logic. Reasonable and effective test case is the important precondition for interlocking test orderly and efficient execution. Therefore to research on the case generation method of subway interlocking based on UML is of great significance for guiding the interlocking test.In order to achieve reliable and formalized model of interlocking logic to generate test cases, UML case diagram is used to describe interlocking function and class diagram is established to describe the relationship between the interlocking route and signal equipment which is additional information for generation of test case. Route selected as an example, the information interaction process between interlocking and other equipment is described by the sequence diagram model. Since the semi-formalization of UML model, formalized definition is cited to make model more accurate expression.The combination fragment is processed to realize the model transformation from UML sequence diagram to event deterministic finite automata(ETDFA) of information interacting objects. Route selected success and failure as end nodes, ETDFA models of objects are synthesized to ETDFA model of interlocking system. According to the test coverage criteria, ETDFA model of system is analyzed by test scenario and the improved depth-first algorithm is used to traversal system model to get testing path. The test case suits of route selected is got by the combination of test scenarios and path information.According to the operation process of route established, optimization strategy of test case is put forward. Network combination algorithm is used to realize the test case combination of route selected and locked. Compared with the method of literatures, the method in this thesis can achieve fewer test cases which are consistent with the software requirements. This method also has good ability of error detection, which can improve the efficiency of interlocking software testing and lay a foundation for the automatic generation of test cases.