V - MODEL

V - MODEL (Verification and Validation Model) :

V - Model (Verification and Validation Model)

• V - Model stands for Verification and Validation Model.
• In the first stage CRS is given to both Developers(DE) and Test Engineers(TE). The DE converts CRS into SRS while the TE review CRS, Write Acceptance Test Plan (TP) and Test Case (TC). Mistakes in the CRS are fixed by the DE and again convert into SRS.
• In the second stage the DE convert SRS to HLD while the TE review SRS, write System TP,TC. Mistakes in the SRS are fixed by the DE and convert into HLD.
• In the third stage the DE convert HLD to LLD while the TE reviews HLD, write Integration TP,TC. Mistakes in  the HLD are fixed by the DE and convert into LLD.
• In the fourth Stage the DE convert LLD to Source code, while the TE review LLD, write Functional TP,TC. Mistakes in the LLD are fixed by the DE and again convert into source code.
• In the fifth stage once the source code is ready the DE dump the source code inside the repository and do unit testing or (White Box Testing - WBT). 

note:

Testing each and every line of the source code is called unit testing or white box testing (done by DE)

• The application is given to the testing team. They do FT, IT, ST, AT and released to the customer.

Advantages 

• Overall investment is less.
• Testing is done from the document level of the software development. Therefore downward flow of defects are reduce.

Drawbacks

• Initial cost is more.
• Too much documentation is involved at every stage of V - Model.

Applications

• We used this model for long term projects.
• Complex projects.
• When the customer demands high quality software we go for V - Model.