V-Shaped Model

Just like the waterfall model, the V-Shaped life cycle is a sequential path of execution of processes. Each phase must be completed before the next phase begins. Testing is emphasized in this model more so than the waterfall model though. The testing procedures are developed early in the life cycle before any coding is done, during each of the phases preceding implementation.

Requirements begin the life cycle model just like the waterfall model. Before development is started, a system test plan is created. The test plan focuses on meeting the functionality specified in the requirements gathering.

The high-level design phase focuses on system architecture and design. An integration test plan is created in this phase as well in order to test the pieces of the software systems ability to work together.

The low-level design phase is where the actual software components are designed, and unit tests are created in this phase as well.

The implementation phase is, again, where all coding takes place. Once coding is complete, the path of execution continues up the right side of the V where the test plans developed earlier are now put to use.

Advantages

a. Simple and easy to use.

b. Each phase has specific deliverables.

c. Higher chance of success over the waterfall model due to the development of test plans early on during the life cycle.

d. Works well for small projects where requirements are easily understood.

Disadvantages

a. Very rigid, like the waterfall model.

b. Software is developed during the implementation phase, so no early prototypes of the software are produced.

c. Model doesn’t provide a clear path for problems found during testing phases.