Test-driven porting

Traditional test driven development focuses on development of new units (classes) driven by programmer-facing unit tests. This paper describes our experiences when using business-facing tests (also known as "story tests") to guide the porting of a legacy application. Domain experts specified tests in a tabular format using Excel spreadsheets. Developers automated these spreadsheets in various ways over time: scripts, generation of JUnit source code, and Fit. These tests were run against the legacy system and guided the development of the newly ported system. We found test driven porting to be an effective way to port a complex application.