WS-BPEL applications are a kind of service-oriented application. They use XPath extensively to integrate loosely-coupled workflow steps. However, XPath may extract wrong data from the XML messages received, resulting in erroneous results in the integrated process. Surprisingly, although XPath plays a key role in workflow integration, inadequate researches have been conducted to address the important issues in software testing. This paper tackles the problem. It also demonstrates a novel transformation strategy to construct artifacts. We use the mathematical definitions of XPath constructs as rewiring rules, and propose a data structure called XPath Rewriting Graph (XRG), which not only models how an XPath is conceptually rewritten but also tracks individual rewritings progressively. We treat the mathematical variables in the applied rewriting rules as if they were program variables, and use them to analyze how information may be rewritten in an XPath conceptually. We thus develop an algorithm to construct XRGs and a novel family of data flow testing criteria to test WS-BPEL applications. Experiment results show that our testing approach is promising.

The incorporation of context-awareness capabilities into pervasive applications allows them to leverage contextual information to provide additional services while maintaining an acceptable quality of service. These added capabilities, however, introduce a distinct input space that can affect the behavior of these applications at any point during their execution, making their validation quite challenging. In this paper, we introduce an approach to improve the test suite of a context-aware application by identifying contextaware program points where context changes may affect the application’s behavior, and by systematically manipulating the context data fed into the application to increase its exposure to potentially valuable context variations. Preliminary results indicate that the approach is more powerful than existing testing approaches used on this type of application. 1

Pervasive computing software adapts its behavior according to the changing contexts. Nevertheless, contexts are often noisy. Context inconsistency resolution provides a cleaner pervasive computing environment to context-aware applications. A faulty context-aware application may, however, mistakenly mix up inconsistent contexts and resolved ones, causing incorrect results. This paper studies how such faulty context-aware applications may be affected by these services. We model how programs should handle contexts that are continually checked and resolved by context inconsistency resolution, develop novel sets of data flow equations to analyze the potential impacts, and thus formulate a new family of test adequacy criteria for testing these applications. Experimentation shows that our approach is promising.

An oracle in software testing is a mechanism for checking whether the system under test has behaved correctly for any executions. In some situations, oracles are unavailable or too expensive to apply. This is known as the oracle problem. It is crucial to develop techniques to address it, and metamorphic testing (MT) was one of such proposals. This paper conducts a controlled experiment to investigate the cost effectiveness of using MT by 38 testers on three open-source programs. The fault detection capability and time cost of MT are compared with the popular assertion checking method. Our results show that MT is cost-efficient and has potentials for detecting more faults than the assertion checking method.

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.

A test oracle in software testing is a mechanism for checking whether the program under test behaves correctly for any execution. In some practical situations, oracles can be unavailable or too expensive to apply. Metamorphic testing (MT) was proposed to alleviate this problem so that software can be delivered under the time-to-market pressure. However, the effectiveness of MT has not been studied adequately. This paper conducts a controlled experiment to investigate the cost effectiveness of using MT. The fault detection capability and time cost of MT are compared with the standard assertion checking method. Our results show that MT has potentials to detect more faults than the assertion checking method. The experiment results also show a trade-off between the two testing methods: MT can be less efficient but more effective, and can be defined at a coarser level of granularity than the assertion checking method.

Abstract—Programs using service-oriented architecture (SOA) often feature ultra-late binding among components. These components have well-defined interfaces and are known as web services. Messages between every pair of web services dually conform to the output interface of a sender and the input interface of a receiver. Unit testing of web services should not only test the logic of web services, but also assure the correctness of the web services during input, manipulation, and output of messages. There is, however, little software testing research in this area. In this paper, we study the unit testing problem to assure components written in orchestration languages, WS-BPEL in particular. We report an empirical study of the effectiveness of the Frankl-Weyuker data flow testing criteria (particularly the all-uses criterion) on WS-BPEL subject programs. Our study shows that conventional

We report on work in progress upon the verification of contextaware applications written in C-based languages. We recognize that context-aware programs are generally either middleware-based and multithreaded, or driven by asynchronous events, and focus on identifying the program points in which the contextual updates impact the application behaviour. Inheriting from related work on the validation of context-aware applications, we implement a technique for detecting context-aware program points over SatAbs, a tool for generic verification of specifications of ANSI C/C++ programs. We then briefly review future work with regard to the automatic verification of these programs

Abstract—Pervasive computing systems often use middleware as a means to communicate with the changing environment. However, the interactions with the context-aware middleware as well as the interactions among applications sharing the same middleware may introduce faults that are difficult to reveal by existing testing techniques. Our previous work proposed the notion of context diversity as a metric to measure the degree of changes in test inputs for pervasive software. In this paper, we present a case study on how much context diversity for test cases relates to fault-based mutants in pervasive software. Our empirical results show that conventional mutation operators can generate sufficient candidate mutants to support test effectiveness evaluation of pervasive software, and test cases with higher context diversity values tend to have higher mean mutation scores. On the other hand, for test cases sharing the same context diversity, their mutation scores can vary significantly in terms of standard derivations. Keywords—context diversity; mutation analysis; pervasive computing I.