This requires a thorough re-testing of these components to ensure that any work as defined in the real context. Beydeda and Gruhn invited leading researchers in the field testing of components to contribute to this monograph that covers all relevant aspects of testing in the context-independent components through component testing in the context of a specific system on complete system testing is built from different components. The authors take the perspective of both developers and users of components, and their contributions include functional requirements such as compliance truth and functions as well as non-functional requirements like performance and endurance. Overall this monograph offers researchers, advanced graduate students and professionals a unique and comprehensive picture about the state of the art in testing COTS components and COTS-based systems.