V MODEL

The V model, while admittedly obscure, gives equal weight to testing and development than  treating testing it as an afterthought. The V model shows the typical sequence of development activities on the left-hand side and the corresponding testing activities on the right-hand side.
In fact, the V model emerged in reaction to some waterfall models that showed testing as a single phase following the traditional development phases of requirement gathering, analysis, design and coding. The Waterfall model did considerable damage by supporting the common impression that testing is merely a brief detour after most of the mileage has been gained by mainline development activities. Many managers still believe this, even though testing usually takes up half of the project time. The V model is the most popular model in the organisation. It uses do-check approach that is every development activity is checked by testing activity. It is also called Verification and Validation model.