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

Engineering framework for service-oriented automation systems

Tese de doutoramento. Engenharia Informática. Universidade do Porto. Faculdade de Engenharia. 201

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

FLACOS’08 Workshop proceedings

The 2nd Workshop on Formal Languages and Analysis of Contract-Oriented Software (FLACOS’08) is held in Malta. The aim of the workshop is to bring together researchers and practitioners working on language-based solutions to contract-oriented software development. The workshop is partially funded by the Nordunet3 project “COSoDIS” (Contract-Oriented Software Development for Internet Services) and it attracted 25 participants. The program consists of 4 regular papers and 10 invited participant presentations

Context Aware Web-Service Monitoring

Monitoring the correct behaviour of a service-based system is a necessity and a key challenge in Service Oriented Computing. Several efforts have been directed towards the development of approaches dealing with the monitoring activity of service-based systems. However, these approaches are in general not suitable when dealing with modifications in service-based systems. Furthermore, existing monitoring approaches do not take into consideration the context of the users and how this context may affect the monitor activity. Consequently, a holistic monitor approach, capable of dealing with the dynamic nature of service-based systems and of taking into consideration the user context, would be highly desirable. In this thesis we present a monitor adaptation framework capable of dealing with changes in a service-based system and different types of users interacting with it. More specifically, the framework obtains a set of monitor rules, necessary to verify the correct behaviour of a service-based system, for a particular user. Moreover, the monitor rules verifying the behaviour of a service-based system relate to properties of the context types defined for a user. The main contributions of our work include the general characterisation of a user interacting with a service-based system and the generation of suitable monitor rules.The proposed framework can be applied to any service composition without the need of further modifications. Our work complements previous research carried on in the area of web service monitoring. More specifically, our work generates a set of suitable monitor rules - related to the user context - which are deployed in a run-time monitor component. Our framework has been tested and validated in several cases considering different scenarios

Framework para la gestión de invariantes dinámicos en WS-BPEL

Este Proyecto de Fin de Carrera (PFC) ha sido realizado en colaboración con el grupo de investigación SPI&FM (Software Process Improvement and Formal Methods) en su línea de Ingeniería Web. Esta línea de investigación se encuentra centrada en el desarrollo y perfeccionamiento de tareas de prueba de software para el lenguaje WS-BPEL. En concreto, el objetivo principal es refactorizar el proceso de generación dinámico de invariantes que realiza Takuan y realizar una interfaz gráfica (denominada IdigInBPEL) para facilitar el uso del sistema

Correctness of services and their composition

We study correctness of services and their composition and investigate how the design of correct service compositions can be systematically supported. We thereby focus on the communication protocol of the service and approach these questions using formal methods and make contributions to three scenarios of SOC.Wir studieren die Korrektheit von Services und Servicekompositionen und untersuchen, wie der Entwurf von korrekten Servicekompositionen systematisch unterstützt werden kann. Wir legen dabei den Fokus auf das Kommunikationsprotokoll der Services. Mithilfe von formalen Methoden tragen wir zu drei Szenarien von SOC bei