SOFTWARE DEFECT REDISCOVERIES: CAUSES, TAXONOMY AND SIGNIFICANCE

A software defect rediscovery is a software failure caused by a previously reported defect. It has been observed that a majority of field software failures are rediscoveries which account for typically 50% but sometimes as much as 90% of the total failures. A number of causes for defect rediscoveries have been identified in the literature and solutions have been designed to address some of them. For an organization aiming at reducing the cost due to the rediscoveries, it is important to understand the significance of each of these causes. The significance of each cause will guide the organization to utilize the known solutions or design new ones if necessary, to ultimately reduce the cost to the organization due to rediscoveries. In this thesis, we identify and define the causes for rediscoveries, both on the side of the software provider as well as the software user and design a taxonomy for these causes. We establish the significance of each of the causes for rediscoveries by conducting two exploratory based empirical case studies. The overall findings of this study suggest that the delay on the software providers’ side to provide the patch contributes to approximately 50% of the rediscoveries; whereas, that on the software users’ side to install the patch contributes to approximately 50% of the rediscoveries. This overall result is further broken down quantitatively into specific causes, which are all described in this thesis. From a practitioner’s point of view, the results of this investigation will provide the decision support regarding the designing and prioritizing of various policies and solutions aimed at reducing the cost due to rediscoveries. From a research point of view, the results of our investigation add to the existing body of knowledge on the causes for rediscoveries in software systems

Change Impact Analysis Based Regression Testing of Web Services

Reducing the effort required to make changes in web services is one of the primary goals in web service projects maintenance and evolution. Normally, functional and non-functional testing of a web service is performed by testing the operations specified in its WSDL. The regression testing is performed by identifying the changes made thereafter to the web service code and the WSDL. In this thesis, we present a tool-supported approach to perform efficient regression testing of web services. By representing a web service as a directed graph of WSDL elements, we identify and gathers the changed portions of the graph and use this information to reduce regression testing efforts. Specifically, we identify, categorize, and capture the web service testing needs in two different ways, namely, Operationalized Regression Testing of Web Service (ORTWS) and Parameterized Regression Testing of Web Service (PRTWS). Both of the approach can be combined to reduce the regression testing efforts in the web service project. The proposed approach is prototyped as a tool, named as Automatic Web Service Change Management (AWSCM), which helps in selecting the relevant test cases to construct reduced test suite from the old test suite. We present few case studies on different web service projects to demonstrate the applicability of the proposed tool. The reduction in the effort for regression testing of web service is also estimated.Comment: Master of Technology Thesis, PDPM Indian Institute of Information Technology, Design and Manufacturing Jabalpur (2014