What is V Model in software testing and what are advantages and disadvantages of V Model

What is V Model testing?

V Model or Verification and Validation Model. Every testing execution should follow some sequence and V Model is the perfect way to perform the testing approaches. In V Model there are some steps or sequences specified which should be followed during performing test approach. Once one step completes we should move to the next step. Test execution sequences are followed in V shape. In software development life cycle, V Model testing should start at the beginning of the project when requirement analysis starts. In V Model project development and testing should go parallel. Verification phase should be carried out from SDLC where validation phase should be carried out from STLC (Software Testing Life Cycle)

Steps in V Model

Basically there are 4 steps involved in STLC while performing V Model testing strategy.

• Unit Testing.
• Integration Testing.
• System Testing.
• Acceptance Testing.

Let’s have a look on the V Model architecture and move to the little more detailed description:

As V Model specifies that test plan should be started form the beginning when requirement phase starts. In above V Model you will see when requirement phase completed acceptance testing and system testing has been planned in parallel. Similarly once design phase completes, Integration testing should be planned and finally once coding phase completes, Unit testing should be planned.

During the execution, testing starts from Unit testing and carries up to Acceptance testing to make sure the application meets all the development phases and working as per expectation.

Advantages of V Model

• If project is small and easy to understand, V Model is the best approach as its easy and simple to use.
• Many testing activities are performed in the beginning like planning and design which saves lots of testing time.
• Most of the defects and bugs are found in the beginning of the project development. So less chances of defect or bug to be occurred at final testing phase.

Disadvantages of V Model

• Guessing the error in the beginning of the project could take more time.
• Less flexibility.
• Any changes done in the middle of the development which is unplanned could make difficult to make the changes at all the places like test document and requirements.

When V Model should be followed.

• V Model should be followed for small project where requirements are clear and easy to understand at the beginning of development.
• V Model should be followed for the project where very less probability to make the changes in the middle of testing or development phase which are unplanned.