V Model

The V model is a Software Development Life Cycle (SDLC) that is based on the Waterfall model and emphasizes the verification and validation of the product. Each phase of this model is paired with a level of testing.

The V model was first implemented in the late twentieth century and has been widely used ever since. It can be divided in five main phases:

1. Requirements analysis
2. System design
3. Architectural design
4. Module design
5. Coding

Except for coding, the other four phases are each linked to a distinct testing activity. Going up from the bottom (module design), those testing activities are, respectively:

• Unit testing
• Integration testing
• System testing
• Acceptance testing

Advantages

• Testing within each stage ensures each requirement is properly checked and validated, and that the product is of high quality and fulfills the requirements.
• Errors and issues can be detected at early stages of development due to an emphasis on testing early and often.
• Easy management and project planning.

Disadvantages

• Unsuitable for large and complex projects or that require constant changes.
• Uncertain and risky due to lack of risk analysis.