In the V-model of software development, which test corresponds to the requirements definition phase and checks that what was decided in that phase is satisfied?

Answer: C. Acceptance testing

The V-model is a development model that places the phases going down from requirements definition through design to implementation on the left, places the testing phases going back up on the right, and links each pair of corresponding phases. Acceptance testing (operational testing) corresponds to requirements definition, and as the design phases become more detailed, system testing, integration testing and unit testing correspond to them in turn. The mapping of the intermediate phases differs slightly between organizations and textbooks, and system testing is sometimes also mapped to requirements definition, but all agree that acceptance testing, which checks the requirements from the customer's or user's point of view, corresponds to requirements definition. The key point of the model is to prepare the test plans and pass criteria at the time of the corresponding design phase.

• A. This test checks that individual modules (functions or classes) work as designed, and corresponds to the lowest phase of the V.
• B. This test checks the interfaces and cooperation when modules are combined, and corresponds to the design phases.
• C. Correct. It checks, from the customer's or user's point of view, that the system can be used as defined in the requirements.