A Method Based One-test-at-a-time Strategy Of Combinatorial Test Case Prioritization

Due to the large combined space in the software system,the combinatorial testing is designed to solve the problem of exploding test case.The number of test cases can be reduced through a system-efficient approach,but testing still doesn’t provide sufficient resources for executing all of the test cases.For this reason,test case prioritization techniques have been introduced in combinatorial testing to prioritize high-contribution test cases.This paper systematically reviews and summarizes the existing results of the prioritization method in combinatorial testing.It is found that the combined coverage is mostly used as the sorting criterion in the existing research,and these methods can reach the combined coverage objective as soon as possible.However,priority sorting factor is single,resulting in a larger difference in the sort results.The prioritization method in combinatorial testing is usually a static process,and in variable strength combinatorial testing,the prioritization method is still faced with the difficulty of selecting strength.In order to improve the existing research deficiencies,this paper proposes a method to prioritize test cases based on One-test-at-a-time(OTT)strategy.The main research work and contributions are summarized as follows:(a)Aiming at the complex and ever-changing interaction among influencing factors in combination testing,the corresponding prioritization methods are proposed respectively from the perspective of combinatorial testing of fixed strength and variable strength.And this method avoids the difficulty of selecting strength in variable strength combinatorial testing.(b)In order to avoid the single problem of sorting factors in the current research,we introduce three sorting factors into the prioritization methods of fixed strength and variable strength combinatorial testing,and calculate the priority of test cases by three weight factors.The priority sorting factors are multi-coverage under coverage rate,test case failure rate and test case importance degree in the fixed strength combinatorial testing.In variable strength combinatorial testing,the priority sorting factors are locally-interaction-coverage rate,test case local failure rate,test case local importance degree.(c)There is a static ordering phenomenon in the prioritization method of combinatorial testing.In this paper,OTT strategy is used to extend the prioritization algorithm,and the highest priority test case is executed after each sorting.In this paper,we propose a strategy of on-line adjustment of prioritization by using test cases executed results.This strategy can achieve the purpose of dynamically ranking priority.In order to reflect the feasibility of the prioritization method in combinatorial testing which is proposed in this paper,we compare the proposed method with the original methods by simulation experiments.The experimental results show that our proposed method can improves the defect detection rate and reduces the number of test cases used per unit defect.