Model-based testing using UML activity diagrams: A systematic mapping study

Context: The Unified Modeling Language (UML) has become the de facto standard for software modeling. UML models are often used to visualize, understand, and communicate the structure and behavior of a system. UML activity diagrams (ADs) are often used to elaborate and visualize individual use cases. Due to their higher level of abstraction and process-oriented perspective, UML ADs are also highly suitable for model-based test generation. In the last two decades, different researchers have used UML ADs for test generation. Despite the growing use of UML ADs for model-based testing, there are currently no comprehensive and unbiased studies on the topic. 

Objective: To present a comprehensive and unbiased overview of the state-of-the-art on model-based testing using UML ADs. 

Method: We review and structure the current body of knowledge on model-based testing using UML ADs by performing a systematic mapping study using well-known guidelines. We pose nine research questions, outline our selection criteria, and develop a classification scheme. 

Results: The results comprise 41 primary studies analyzed against nine research questions. We also highlight the current trends and research gaps in model-based testing using UML ADs and discuss some shortcomings for researchers and practitioners working in this area. The results show that the existing approaches on model-based testing using UML ADs tend to rely on intermediate formats and formalisms for model verification and test generation, employ a multitude of graph-based coverage criteria, and use graph search algorithms. 

Conclusion: We present a comprehensive overview of the existing approaches on model-based testing using UML ADs. We conclude that (1) UML ADs are not being used for non-functional testing, (2) only a few approaches have been validated against realistic, industrial case studies, (3) most approaches target very restricted application domains, and (4) there is currently a clear lack of holistic approaches for model-based testing using UML ADs.