Test Driven Decomposition of Legacy Systems into Services

A number of questions have been raised by both practitioners and researchers regarding the compatibility of service oriented architectures and agile methods. These are compounded when both approaches are combined to maintain and migrate legacy systems. In particular, where test driven development is practiced as a core component of an agile development process, both legacy systems and service oriented architectures can present an incongruous set of development challenges. In this chapter, the authors provide experience reports on how legacy systems have been adapted to an agile, test driven development context by a process of decomposition into testable services. They describe two domains and technology contexts where automated agile testing at multiple interface layers has improved both quality of service and functionality.