Figure 1. V-Model, shows the seven distinct stages of testing and where each stage occurs within the system’s development cycle. The left side of the “V” indicates the source documents (requirements, design, and detailed design and build) from which test cases are formulated. The right side of the “V” shows the stages of testing; unit test, system qualification test, system integration test, configuration and quality management staff test, user acceptance test, performance test, and operational readiness test. Each stage tests a broader level of functional and technical complexity than the previous stage. Accordingly, test conditions in each successive stage of testing are derived from successively higher-level sources. For example, “low level” unit tests are derived from the conditions specified in the detailed design, while “high level” unit tests are derived from user acceptance testing conditions from the system requirements or use cases.
