V-Model is one of the most powerful model which is used in the software development. V-Model is like the extension of the waterfall model, it means its better then the waterfall model. many models which is used currently in the software development are connected by the V-Model and as per the name V-Model, V describe the arrangement of all phases in the graphical shape of V. V used in the V-Model because its a synonym of validation and verification. Instead of moving down in a linear way, the process steps are bent upwards after the coding phase, to form the typical V shape. in the V-Model the order of the activities are in sequence and its provide better flow in the development and test activities. V- Model provide excellent relationship of each phases used in the system development life cycle.
AS per the name the Spiral Model is cyclical and prototyping view of software development. Spiral Model test phase is divided in to stages and its covers risk analysis, validation of requirements and of the development of the system or application or software. In all the test we need to include module, integration and acceptance tests but in the Spiral Model testing its also follows the coding. In the Spiral Model first the design of the system is implemented and then the test plan implemented. If no activities associated with defects removal then its identifies by the spiral model.
The Waterfall Model
Waterfall Model is the first models of software development, Mr. B.W.Boehm is the created of Waterfall Model. In the Waterfall Model we achieving the tasks step by step means the one by one. so we finish the first step or first phase and then move on the next step or next phase of development cycle. we can no jump on the next phase without completing the current phase. when we moved on the next phase and some problem then we can go back only to the previous phase. In waterfall model verification and validation activities are define on all the phase of the system development. so once phase is completed then the testing team work on that phase and then development team move on the next phase after getting the approval of the testing team. in any circumstance we can go in the previous phase of the system but its only one step. it means if we work on the 4 phase then we can move on 3 phase but do not move on the 1 phase.
I hope this should be clear your mind on the waterfall model.
Testing Models which is used in the Software Development
1) Waterfall Model.
2) Spiral Model.
3) V Model.
4) W Model.
5) Butterfly Model.