The V-Model is considered an extension of the Waterfall Model. The purpose of the “V” shape is to demonstrate the relationships between each phase of specification development and its associated dynamic testing phase. This model clearly shows the inverse relationship between how products move from high level concepts to detailed program code; then, dynamic testing begins at the detailed code phase and progresses to the high level user acceptance test phase.

On the left side of the “V,” often referred to as the specifications side, verification test techniques are employed (to be described later in this skill category). These verification tests test the interim deliverables and detect defects as close to point of origin as possible. On the right hand side of the “V,” often referred to as the testing side, validation test techniques are used (described later in this skill category). Each of the validation phases test the counter opposed specification phase to validate that the specification at that level has been rendered into quality executable code

The V-Model enables teams to significantly increase the number of defects identified and removed during the development life cycle by integrating verification tests into all stages of development. Test planning activities are started early in the project, and test plans are detailed in parallel with requirements. Various verification techniques are also utilized throughout the project to:

– Verify evolving work products
Software Testing Principles and Concepts
– Test evolving applications by walking through scenarios using early prototypes
– Removing defects in the stage of origin (phase containment) results in:
– Shorter time to market
– Lower error correction costs
– Fewer defects in the production system
– Early test planning yields better test plans that can be used to validate the application against requirements
– Regardless of the development methodology used, understanding the V-model helps the tester recognize the dependence of related phases within the life cycle.