Research On Fault Injection For The Performance Testing Of Web Services

In recent years,Service-Oriented Architecture(SOA)has been increasingly used in distributed software system architectures.Web services now can be found in various civil bussiness systems and military embedded devices.Testing is a key step in the process of Web services development.It is of great importance for the discovering of defects in Web services in order to ensure the quality of services.At present,the research on Web services testing mainly focuses on functional testing,with little attention on the performance testing of services.Traditional performance testing is difficult to systematically assess the performance of loose coupling systems like Web services,especially to assess the impact of the instability of sub-services on the performance of composite services.The performance of a composite service depends on the performance of its sub-services which may be provided by third-parties.There can be many unstable factors occurring in the sub-services,and it is difficult to ensure such factors appear during the testing process.As a consequence,the traditional testing techniques are unable to effectively analyze the impact of unstableness in the performance of sub-services on the overall performance of the composite services.The main research work of this theis are follows:(1)We propose a systematic automatic fault injection approach for the performance testing of composite services.In the approach,we first define serveral fault injection test coverage criteria for performance problem detection,including sub-service single invocation delay coverage,sub-service multiple invocation delay coverage,and sub-service stability coverage.Based on these coverage criteria,as well as test cases for composite services,a set of fault injection configurations will be automatically generated and the fault injection process is then automatically conducted under these fault injection configurations.(2)We propose a performance specifition language to help detected unexpected performance of Web services during fault injection testing.The specification can check overlong service response time,too large response time deviation,service invoke timeout,etc.,and the language allows defining very flexible checking rules,with which the identification of performance problems in Web services can be largely automated.(3)A Web service fault injection tool is implemented to inject the performance related anomalys into the Web service and determine whether the performance of a service is as expected.Experiments on several representative Web services show that the proposed approach is effective.