Data flow testing of service choreography

This work is supported in part by the General Research Fund of the Research Grants Council of Hong Kong (project nos. 717506 and 717308).ESEC/FSE (Conference)Service computing has increasingly been adopted by the industry, developing business applications by means of orchestration and choreography. Choreography specifies how services collaborate with one another by defining, say, the message exchange, rather than via the process flow as in the case of orchestration. Messages sent from one service to another may require the use of different XPaths to manipulate or extract message contents. Mismatches in XML manipulations through XPaths (such as to relate incoming and outgoing messages in choreography specifications) may result in failures. In this paper, we propose to associate XPath Rewriting Graphs (XRGs), a structure that relates XPath and XML schema, with actions of choreography applications that are skeletally modeled as labeled transition systems. We develop the notion of XRG patterns to capture how different XRGs are related even though they may refer to different XML schemas or their tags. By applying XRG patterns, we successfully identify new data flow associations in choreography applications and develop new data flow testing criteria. Finally, we report an empirical case study that evaluates our techniques. The result shows our techniques are promising in detecting failures in choreography applications. Copyright 2009 ACM.postprin

Preemptive regression test scheduling strategies: a new testing approach to thriving on the volatile service environments

A workflow-based web service may use ultra-late binding to invoke external web services to concretize its implementation at run time. Nonetheless, such external services or the availability of recently used external services may evolve without prior notification, dynamically triggering the workflow-based service to bind to new replacement external services to continue the current execution. Any integration mismatch may cause a failure. In this paper, we propose Preemptive Regression Testing (PRT), a novel testing approach that addresses this adaptive issue. Whenever such a late-change on the service under regression test is detected, PRT preempts the currently executed regression test suite, searches for additional test cases as fixes, runs these fixes, and then resumes the execution of the regression test suite from the preemption point. © 2012 IEEE |postprin

A subsumption hierarchy of test case prioritization for composite services

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Generación dinámica de invariantes para composiciones de servicios web en WS-BPEL

En los últimos años, las arquitecturas orientadas a servicios están cambiando la filosofía de desarrollo de software en muchos entornos. El uso de servicios web facilita significativamente la interoperabilidad entre sistemas, permitiendo programar sistemas de gran tamaño usando otros más simples de manera sencilla. El principal lenguaje para componer servicios es WS-BPEL 2.0, que ha sido estandarizado por OASIS con la participación de las grandes empresas del sector informático. Sin embargo, las principales técnicas de prueba no han sido adaptadas a WS-BPEL, quedando como uno de los principales retos para su adopción. El objetivo de esta tesis es estudiar la validez de la generación dinámica de invariantes (también conocida como generación de invariantes potenciales) para apoyar la prueba de caja blanca de composiciones de servicios web en WS-BPEL. En primer lugar, la tesis comprueba la viabilidad de la generación dinámica de invariantes para WS-BPEL. Para ello se presenta una arquitectura basada en el generador dinámico de invariantes Daikon, que ha demostrado ser útil para lenguajes imperativos como C/C++, Java y Perl. Daikon es software libre, y se ha integrado con código propio y otros dos sistemas libres: el motor de ejecución compatible WS-BPEL 2.0 ActiveBPEL y la biblioteca de prueba unitaria para WS-BPEL BPELUnit, que incorpora un mecanismo de simulación de servicios web (pues puede haber servicios no disponibles para pruebas). Los tres sistemas han sido adaptados para crear Takuan, el único generador dinámico de invariantes para WS-BPEL hasta la fecha. Tras implementar Takuan se realizaron pruebas para comprobar la utilidad de los invariantes que generaba. En ellas se observaron diversas mejoras específicas de WS-BPEL que permitirían optimizar su rendimiento. Tras implementarlas y evaluarlas, se obtuvo una mejora sustancial tanto en el tiempo de ejecución de Takuan como en la cantidad de invariantes que produce, descartando muchos invariantes no informativos y redundantes. Una vez estuvieron dichas mejoras implementadas se demostró la estabilidad de los invariantes generados por Takuan, permitiendo asegurar su correcto funcionamiento con un conjunto soporte adecuado. Los resultados obtenidos permiten afirmar la validez de la generación dinámica de invariantes para apoyar la prueba de caja blanca de composiciones WS-BPEL

Automated Realistic Test Input Generation and Cost Reduction in Service-centric System Testing

Service-centric System Testing (ScST) is more challenging than testing traditional software due to the complexity of service technologies and the limitations that are imposed by the SOA environment. One of the most important problems in ScST is the problem of realistic test data generation. Realistic test data is often generated manually or using an existing source, thus it is hard to automate and laborious to generate. One of the limitations that makes ScST challenging is the cost associated with invoking services during testing process. This thesis aims to provide solutions to the aforementioned problems, automated realistic input generation and cost reduction in ScST. To address automation in realistic test data generation, the concept of Service-centric Test Data Generation (ScTDG) is presented, in which existing services used as realistic data sources. ScTDG minimises the need for tester input and dependence on existing data sources by automatically generating service compositions that can generate the required test data. In experimental analysis, our approach achieved between 93% and 100% success rates in generating realistic data while state-of-the-art automated test data generation achieved only between 2% and 34%. The thesis addresses cost concerns at test data generation level by enabling data source selection in ScTDG. Source selection in ScTDG has many dimensions such as cost, reliability and availability. This thesis formulates this problem as an optimisation problem and presents a multi-objective characterisation of service selection in ScTDG, aiming to reduce the cost of test data generation. A cost-aware pareto optimal test suite minimisation approach addressing testing cost concerns during test execution is also presented. The approach adapts traditional multi-objective minimisation approaches to ScST domain by formulating ScST concerns, such as invocation cost and test case reliability. In experimental analysis, the approach achieved reductions between 69% and 98.6% in monetary cost of service invocations during testin