U. De Carlini

Testing Web applications

The rapid diffusion of Internet and open standard technologies is producing a significant growth of the demand of Web sites and Web applications with more and more strict requirements of usability, reliability, interoperability and security. While several methodological and technological proposals for developing Web applications are coining both from industry and academia, there is a general lack of methods and tools to carry out the key processes that significantly impact the quality of a Web application (WA), such as the validation & verification (V&V), and quality assurance. Some open issues in the field of Web application testing are addressed in this paper. The paper exploits an object-oriented model of a WA as a test model, and proposes a definition of the unit level for testing the WA. Based on this model, a method to test the single units of a WA and for the integration testing is proposed. Moreover, in order to experiment with the proposed technique and strategy, an integrated platform of tools comprising a Web application analyzer, a repository, a test case generator and a test case executor, has been developed and is presented in the paper. A case study, carried out with the aim of assessing the effectiveness of the proposed method and tools, produced interesting and encouraging results.

WARE: a tool for the reverse engineering of Web applications

The development of Web sites and applications is increasing dramatically to satisfy the market requests. The software industry is facing the new demand under the pressure of a very short time-to-market and an extremely high competition. As a result, Web sites and applications are usually developed without a disciplined process: Web applications are directly coded and no, or poor, documentation is produced to support the subsequent maintenance and evolution activities, thus compromising the quality of the applications. This paper presents a tool for reverse engineering Web applications. UML diagrams are used to model a set of views that depict several aspects of a Web application at different abstraction levels. The recovered diagrams ease the comprehension of the application and support its maintenance and evolution. A case study, carried out with the aim of assessing the effectiveness of the proposed tool, allowed relevant information about some real Web applications to be successfully recovered and modeled by UML diagrams.

Comprehending Web applications by a clustering based approach

The number and complexity of Web applications are increasing dramatically to satisfy market needs, and the need of effective approaches for comprehending them is growing accordingly. Recently, reverse engineering methods and tools have been proposed to support the comprehension of a Web application; the information recovered by these tools is usually rendered in graphical representations. However, the graphical representations become progressively less useful with large-scale applications, and do not support adequately the comprehension of the application. To overcome this limitation, we propose an approach based on a clustering method for decomposing a Web application (WA) into groups of functionally related components. The approach is based on the definition of a coupling measure between interconnected components of the WA that takes into account both the typology and topology of the connections. The coupling measure is exploited by a clustering algorithm that produces a hierarchy of clustering. This hierarchy allows a structured approach for comprehension of the Web application to be carried out. The approach has been experimented with medium sized Web applications and produced interesting and encouraging results.

A logic-based approach to reverse engineering tools production

Difficulties arising in the use of documents produced by reverse engineering tools are analyzed. With reference to intermodular data flow analysis for Pascal software systems, an interactive and evolutionary tool is proposed. The tool is based on the production of intermodular data flow information by static analysis of code, its representation in a Prolog program dictionary, and a Prolog abstractor that allows the specific queries to be answered. >

Recovering use case models from object-oriented code: a thread-based approach

Use case models describe the behavior of a software system from the users perspective. This paper presents a reverse engineering approach for recovering a use case model from object-oriented code. The approach identifies use cases by analyzing class method activation sequences triggered by input events and terminated by output events. The approach produces a structured use case model including diagrams at various levels of abstraction, comprising actors, use cases, associations between actors and use cases, and relationships among use cases. A case study carried out to validate the approach on a C++ small-sized system, produced encouraging results, showing the approach feasibility and highlighting aspects of the approach requiring further investigation.

An extensible system for source code analysis

Constructing code analyzers may be costly and error prone if inadequate technologies and tools are used. If they are written in a conventional programming language, for instance, several thousand lines of code may be required even for relatively simple analyses. One way of facilitating the development of code analyzers is to define a very high-level domain-oriented language and implement an application generator that creates the analyzers from the specification of the analyses they are intended to perform. This paper presents a system for developing code analyzers that uses a database to store both a no-loss fine-grained intermediate representation and the results of the analyses. The system uses an algebraic representation, called F(p), as the user-visible intermediate representation. Analyzers are specified in a declarative language, called F(p)-l, which enables an analysis to be specified in the form of a traversal of an algebraic expression, with access to, and storage of, the database information the algebraic expression indices. A foreign language interface allows the analyzers to be embedded in C programs. This is useful for implementing the user interface of an analyzer, for example, or to facilitate interoperation of the generated analyzers with pre-existing tools. The paper evaluates the strengths and limitations of the proposed system, and compares it to other related approaches.

Reverse engineering processes, design document production, and structure charts

Abstract This article describes a high-level organizational paradigm for setting up reverse engineering processes capable of automatically generating design-level information and documents straight from code. It also illustrates an instantiation of the paradigm for the reconstruction of the structure charts of a software system according to the Yourdon-Constantine methodology. Discussion focuses on the reconstruction of structure charts at different levels of detail by means of information abstraction processes. These processes use an algebraic model to represent a software module and generate the structure charts of a whole system by successive abstractions of the data represented in the algebraic model of each of its modules.

Abstracting business level UML diagrams from Web applications

In this paper, a reverse engineering approach for reconstructing UML diagrams at business level of the application domain of a Web application is presented. In particular, the approach allows the reconstruction of the UML class diagram providing an object-oriented conceptual model of the application domain, sequence diagrams modeling the interactions among the identified business objects and use case diagrams modeling the user functionalities provided by the Web Application. Heuristic criteria exploiting source code analysis are used for recovering the diagrams. Tools for implementing these criteria have been produced, and experiments for validating them have been carried out with the support of case studies. Experimental results showed the feasibility and the effectiveness of the proposed approach.

Incremental migration strategies: data flow analysis for wrapping

Incremental migration strategies entail the decomposition of large legacy systems in components that can be independently and selectively replaced; this reduces the costs and risks of a migration program. The legacy components are encapsulated into object wrappers and used (through the wrapper interface) in their original form until new components take up their functions with an acceptable level of reliability. The decomposition of legacy programs in components to be encapsulated in different wrappers involves reengineering activities for creating a new program for each component. Data flow analysis methods are needed for identifying the formal parameters in the interfaces of such programs. We present the approach defined within the project ERCOLE, a research project aiming at migrating legacy systems towards object-oriented platforms.

Recovering a business object model from a Web applications

The growing market request for Web applications is forcing software industries to produce applications under the pressure of a short time-to-market and a strong competition, with the consequence that low quality and poor documented software is often produced. Maintaining, evolving or comprehending these applications are not straightforward tasks, and reverse engineering processes should be defined and validated to support them. In this paper a reverse engineering approach for reconstructing an object-oriented conceptual model of the application domain of a Web application is presented. The proposed approach defines a process that reconstructs the model in three steps. In each step, heuristic criteria exploiting source code analysis are used for the identification of objects and their relationships. Tools for implementing this method have been produced, and experiments for validating it have been carried out with the support of case studies. Experimental results showed the feasibility and the effectiveness of the proposed approach.