Raymond A. Paul

Extending WSDL to facilitate Web services testing

Web services might be the most popular and powerful software development technology in todays software world. Yet it brings software developers and testers a lot of challenges also. This is mainly caused by the insufficient information provided by the WSDL file of a Web service. From the WSDL file, we can not get the information useful for testing, such as dependence information. To solve this problem, we proposed and practiced to extend the WSDL to support this kind of information description. In this paper, four kinds of extension are considered: input-output dependency, invocation sequence, hierarchical functional description and concurrent sequence specifications. Also their advantages are discussed.

Automated model checking and testing for composite Web services

Web services form a new distributed computing paradigm. Collaborative verification and validation are important when Web services from different vendors are integrated together to carry out a coherent task. This paper presents a new approach to verify Web services by model checking the process model of OWL-S (Web ontology language for Web services) and to validate them by the test cases automatically generated in the model checking process. We extend the BLAST, a model checker that handles control flow model naturally, to handle the concurrency in OWL-S. We also propose enhancement in OWL-S and PDDL (Planning Domain Definition Language) to facilitate the automated test case generation. Experiments on realistic examples are provided to illustrate the process.

Verification of Web services using an enhanced UDDI server

The UDDI (Universal Description Discovery and Integration) provides classification to find the distributed Web services (WS) by keyword matching. The UDDI version 3 allows searching WS using digital signatures. However, it still needs systematic verification to ensure WS quality in a timely fashion. This paper proposes adding verification mechanism to the UDDI servers including check-in and checkout of WS. The key idea is that test scripts should be attached to WS, and both WS providers and clients use these test scripts. Before accepting a new WS into the service directory. The associated test scripts must test the new WS, and they will be accepted only if the test was successful. Before using a specific WS, a client can use the appropriate test scripts to test the WS and it will be used only if the test was successful. While the code for WS may not be available, but the associated test scripts test script specification techniques and distributed test execution techniques to perform testing with a UDDI server.

Coyote: an XML-based framework for Web services testing

Web services received significant attention recently and several important Web service platforms such as .NET are now available. The testing and evaluation of Web services are important for both service providers and subscribers. This paper proposes an XML-based object-oriented testing framework Coyote to test Web services rapidly. Coyote consists of two parts: test master and test engine. The test master allows testers to specify test scenarios and cases as well as performing various analyses such as dependency analysis, completeness and consistency, and converts WSDL specifications into test scenarios. The test engine interacts with the Web services under test, and provides tracing information. The test framework incorporates concepts from object-oriented application frameworks so that it is relatively easy to change test scenarios/cases. Due to the distributed nature of Web services, Coyote focuses on integration testing instead of module testing.

Cooperative and group testing in verification of dynamic composite Web services

Verifying Web services (WS) in a dynamic Service Oriented Architecture (SOA) is challenging because new services can be composed at runtime using existing WS. Furthermore, in a composite service, any component can be dynamically replaced during execution if the component fails. Another challenge is that the testing is time critical because verification must be conducted at runtime and in real time. We compare and contrast traditional software testing and WS testing techniques and propose a WS group testing technique to test composite services. The group testing technique also has the ability to evaluate the test scripts, automatically establish the oracle of the each test script, and identify faulty WS in a failed composite WS.

Adaptive testing, oracle generation, and test case ranking for Web services

Web services and service-oriented architecture are emerging technologies that are changing the way we develop and use computer software. Due to the standardization of Web services related description languages and protocols, as well as the open platforms, for the same Web service specification, many different implementations can be offered from different service providers. This paper presents an adaptive group testing technique that can test large number Web services simultaneously and effectively. Based on a case study, experiments are performed to validate the correctness and effectiveness of the technique.

Services-oriented dynamic reconfiguration framework for dependable distributed computing

Recently service-oriented architecture (SOA) has received significant attention and one reason is that it is potentially survivable as services are located, bound, and executed at runtime over the Internet. However, this is not enough for dependable computing because the system must also be able to reconfigure once a system failure or overload is detected, and this reconfiguration must be done in real-time at runtime with minimum disruption to the current operation. This work presents reconfiguration requirements for building dependable SOA, and proposes a dynamic reconfiguration framework based on distributed monitoring, synchronization, and runtime verification with distributed agents.

Developing and assuring trustworthy Web services

Web services are emerging technologies that are changing the way we develop and use computer systems and software. Current Web services testing techniques are unable to assure the desired level of trustworthiness, which presents a barrier to WS applications in mission and business critical environments. This paper presents a framework that assures the trustworthiness of Web services. New assurance techniques are developed within the framework, including specification verification via completeness and consistency checking, specification refinement, distributed Web services development, test case generation, and automated Web services testing. Traditional test case generation methods only generate positive test cases that verify the functionality of software. The Swiss cheese test case generation method proposed in this paper is designed to perform both positive and negative testing that also reveal the vulnerability of Web services. This integrated development process is implemented in a case study. The experimental evaluation demonstrates the effectiveness of this approach. It also reveals that the Swiss cheese negative testing detects even more faults than positive testing and thus significantly reduces the vulnerability of Web services.

DDSOS: a dynamic distributed service-oriented simulation framework

This paper presents the DDSOS framework developed at Arizona State University, which supports the simulation, development, and evaluation of large scale distributed systems such as network-centric and system-of-systems applications. The distinct features of the framework include automated simulation code generation from the specification, code deployment, simulation of different architectures with a template-based platform builder, service-oriented multi-agent simulation for easy reconfiguration, and dynamic analyses of results from evaluation and monitoring. The framework and the associated tools have been implemented and applied in several governmental and industrial projects.

Architecture classification for SOA-based applications

The architecture of SOA-based applications is different from traditional software architecture where the architecture is mainly static. The architecture of an SOA-based application is dynamic, i.e., the application may be composed at runtime using existing services. Thus SOA has provided a new direction for software architecture study, where the architecture is determined at runtime and architecture can be dynamically changed at runtime to meet the new software requirements. This paper proposes an architecture classification scheme for SOA-based applications. Using this classification, several well-known SOA-based applications are reviewed including the architectures proposed and adopted by major computer companies and standard organizations. The architecture classification provides a unified way to evaluate a variety of architectures for SOA-based applications