On-board Function Testing Of Next-Generation Train Control System Based On Combinatorial Testing Method

Testing is an effective means to ensure the functional correctness of New Train Control System(NTCS)software.However,as the NTCS on-board equipment takes on more functions of the ground equipment and its software scale breaks through the order of magnitudes of millions of lines,the core safety functions(the calculation of movement authority and speed monitoring curve,etc.)have the characteristics of large parameter input field,multiple failure modes,high parameter dimensions and complex constraints between parameters,and the traditional testing method is not applicable,so it is of great importance to explore an effective testing method for NTCS on-board software.The main work of this paper is summarized as follows:(1)Research on the testing requirements of NTCS based on vehicle to vehicle communication.The overall framework,core modules and their functions(the calculation of mode curve,conversion of mode,digital map,train management,route control,etc.)of NTCS were analyzed.Taking the on-board software as the object under test,through studying the input/output features and characteristics of the interface parameters,the functional testing requirements of the on-board equipment of NTCS were extracted.Moreover,on the basis of the in-depth research on the current situation of the train control system testing worldwide,the features and characteristics of complex parameters of the NTCS software functional testing were analyzed in depth,and the functional testing based on combinatorial testing method was proposed;(2)Research on the combinatorial testing method of NTCS.The method flow of the combinatorial testing was studied,and three different combination test case generation algorithms were analyzed: algebraic method,evolutionary algorithm and greedy algorithm;Three different combinatorial testing strategies of IPOG,IPOG-D and IPOG-D with constraint processing were studied in depth,the combinatorial testing strategy of IPOG was optimized,aiming at the characteristics of high parameter dimensions and complex constraint between parameters of NTCS,(3)A functional testing framework for on-board software of NTCS based on combinatorial testing method was proposed.Firstly,the functional structure of NTCS was hierarchically divided,the input and output parameters of each hierarchy of the system under testing were determined,and the interactions and constraints between theparameters were identified;Secondly,based on the combinatorial testing method,the combinatorial testing model Model SUT(P,V,R,C)of the NTCS on-board software is established;Then,the IPOG combinatorial testing strategy was used to generate test cases;Finally,the effectiveness of the NTCS test suite was analyzed by using the fault detection principle based on mutation.(4)A case study of combinatorial testing on the typical functions of NTCS on-board software.A combinatorial testing model was established for the on-board overspeed protection of NTCS,and IPOG-C was used to generate a test combination consisting of four environmental parameters,on this basis,based on the three algorithms of IPOG,IPOG-D and C-IPOG-D,a test suite satisfying the coverage of different dimensions of parameters was obtained;At the same time,in order to verify the improvement effectiveness of IPOG algorithm,a quantitative analysis was made on the scale and generation time of the test suite generated by IPOG algorithm and IPOG-D algorithm from the three aspects of coverage strength,number of parameters and value range of parameters.(5)The test case generation and evaluation tool covering the three different combination strategies of IPOG,IPOG-D and C-IPOG-D was designed and developed.According to the above case study above,the effectiveness evaluation of the test suite was carried out.At the same time,in order to evaluate the generation effect of test suite,this method was compared with the random testing method in the aspect of fault detection.The experiment shows that the capability of fault detection of combinatorial testing is better than that of random testing under the same scale of test suite.This research shows that the NTCS software functional test method based on combinatorial testing has higher coverage strength of test case and higher capability of fault detection than the traditional random testing method when applied to the system with the characteristics of multi-parameter,high dimension and complex fault mode,and thus is suitable for the functional test of NTCS.Figure 42,Table 24,References 91.