Research On CPN Model Reduction Focus On Parallel Tested Behaviors

With the rapid development of software industry,parallel software system has become the mainstream of a software system,become more and more important role in people's lives.Such as the cloud computing software,network software and other software systems have the characteristics of parallel behavior.As the key process,software testing plays an important role in ensuring the quality of software.However,because of its parallel characteristics,the parallel software can easily lead to the explosion of state space,and most of the traditional test methods generate the full test sequences based on the state space.They could not work efficient when the state space is exploded,and usually leads to the problems like the low coverage,high redundancy,and low test efficiency.The method of reducing the state space by model simplification can effectively reduce the complexity of parallel software testing and the key problem in the study of simplified method is to ensure that the effect of testing before and after simplification is consistent.At present,the method of software simplification for software testing is mainly based on the simplification of trace equivalence.Such methods can not reduce the complexity of concurrent execution,so the simplification is limited.In this dissertation,focus on tested behaviors and its related behavior to simplify the parallel software system.The branches that are independent of the tested behaviors are sequentially processed and restricted processing to achieve the purpose of reducing the state space,and ensure the effect of testing after simplification keep consistent.This dissertation about the simplified method to do the following aspects of the work:(1)For the complex parallel mode,the concepts such as the behavior to be tested and the related behaviors are defined,and they are used to respectively describe the test purpose and the related behaviors of test purpose.In the process of simplification of the model,this method only simplifies the non-test behaviors,not only ensuring the correctness of the method,but also reducing the size of the state space,thus enhancing the efficiency of the test.(2)The concept of homology branch is proposed,the homology branch is divided into concurrent branch group or selective branch set,and the simplified operation is carried out in the concurrent branch group or the selective branch set.Since all branches of a concurrent branch group or a selected branch set are from the same source node,homology ensures that the branches that are independent of the behavior to be tested can serialize and process restricted,and they do not affect the effect of testing focus on related behavior to be tested.(3)In the case of a concurrent branch group or a selective branch set,the branches independent of the behaviors to be test are sterilized by adding the inhibitor arc according to the existence of the behaviors to be test and the related behaviors in branches.By adding inhibitor arc does not modify any elements of the model,but only restrict the concurrent execution order and partial independent branches' processing,that ensure the correctness of the model after the simplification.The serialization of concurrent branches and restricted the choice of selective branches could significantly reduce the state space,these operations do not contain the tested behaviors and the related behaviors,so results of testing focused on the tested behaviors remain unchanged.Finally,by analysis of an example,the correctness of the method and the effect of the reduction of the state space of the software model are verified.