Executable Documentation: Test-First in Action

Regarding documentation as anything that supports understanding , we present two test-first scenarios of executable documentation that involve and support different roles during program development through concrete data visualizations. The first is a teaching scenario. Within classical programming, different stages of executable documentation provide faceted layers of self-learning and user-centric diagnostics. Students and teachers benefit from auto-didactic exploration, appropriate diagram syntheses for runtime visualization, and automated test case generation. The latter can be created using reference implementations provided by the teacher but can also be used to foster the dialog between students and tutors. The second scenario introduces a new approach to WYSIWYG GUI editing that is able to render the runtime GUI appearance in real-time within the editor. Using scenario-based test cases, users can seamlessly experience, inspect, and test the GUI while they are editing. The paper discusses the impact of the provided tangible experiences and their role in modern IDEs.