Abstract: Fault localization is an important research topic in the process of software development.However,the number of faults in the actual software cannot be determined in advance.The available single fault localization technique is not convenient to be used,and the available multi-fault localization technique is of low locating efficiency.This paper studied and improved the multi-fault localization technique GAMFL,and proposed a new spectrum-based fault localization methoid combining hitting set and genetic algorithm(GAHIT).In this method,the basic block for localization is defined and used to replace statements to localize faults,narrowing the search range.In the process of constructing initial population,the method of solving the hitting sets of execution path of failure test cases is presented to optimize the generation of initial population,and a new method for calculating fitness function is also presented to improve the total efficiency of the algorithm.According to the results of genetic algorithm,the fault detecton strategy is presented to improve the accuracy of localizing faults in the optimal group.The experiment results show that the proposed method is effective in solving the problem of localizing programs with unknown number of faults,and has good performance when localizing faults in both single fault programs and multi-fault programs.

Key words: Fault localization, Genetic algorithm, Hitting set, Uncertainty of fault number