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The emerging industrial trend towards agile software development processes brings forth new concerns, challenges as well as opportunities. One of the main concerns is with respect to the achievable quality levels of the final product, for which testing is the well-known assurance mechanism. However, it is not well defined for the community on how to perform testing using existing expertise in an agile environment. This uncertainty may create confusion and contra productivity that can lead to testing teams and their practices considered as an obstacle for full implementation of agile processes within an organisation.

This thesis outlines our current research activities towards identifying and addressing important organisational and technical challenges in the agile environment.  In this context, we propose a new role for traditional testers which will enable them to integrate into the agile team as well as to fully exploit their knowledge in the new context. We have conducted an elaborate industrial survey on the preferences and practices with respect to the contemporary aspects of software testing and identified test-driven development as an important technical area for improvement.  A systematic review on empirical evidences related to test-driven development was performed subsequently, which revealed a list of factors limiting its widespread industrial acceptance. Knowledge of testing was identified as one of those factors and was further investigated in a controlled experiment performed with undergraduate students.

Our future works aim to confirm these research findings in wider as well as industrial settings and investigate other limiting factors in detail, with the aim of providing guidelines for achieving better utilisation of testers and testing practices.

One of the most emphasised software testing activities in an Agile environment is the usage of the Test Driven Development (TDD) approach. TDD is a development activity where test cases are created by developers before writing the code, and all for the purpose of guiding the actual development process. In other words, test cases created when following TDD could be considered as a by-product of software development. However, TDD is not fully adopted by the industry, as indicated by respondents from our industrial survey who pointed out that TDD is the most preferred but least practised activity.

Our further research identified seven potentially limiting factors for industrial adoption of TDD, out of which one of the prominent factor was lack of developers’ testing skills. We subsequently defined and categorised appropriate quality attributes which describe the quality of test case design when following TDD. Through a number of empirical studies, we have clearly established the effect of “positive test bias”, where the participants focused mainly on the functionality while generating test cases. In other words, there existed less number of “negative test cases” exercising the system beyond the specified functionality, which is an important requirement for high reliability systems. On an average, in our studies, around 70% of test cases created by the participants were positive while only 30% were negative. However, when measuring defect detecting ability of those sets of test cases, an opposite ratio was observed. Defect detecting ability of negative test cases were above 70% while positive test cases contributed only by 30%.

We propose a TDD^HQ concept as an approach for achieving higher quality testing in TDD by using combinations of quality improvement aspects and test design techniques to facilitate consideration of unspecified requirements during the development to a higher extent and thus minimise the impact of potentially inherent positive test bias in TDD. This way developers do not necessarily focus only on verifying functionality, but they can as well increase security, robustness, performance and many other quality improvement aspects for the given software product. An additional empirical study, evaluating this method, showed a noticeable improvement in the quality of test cases created by developers utilising TDD^HQ concept. Our research findings are expected to pave way for further enhancements to the way of performing TDD, eventually resulting in better adoption of it by the industry.