Verification and validation

Verification
Have we built the software right (i.e., does it match the specification)? Software testing is just one kind of verification, which also uses techniques such as reviews, inspections, and walkthroughs

Validation:
Have we built the right software (i.e., is this what the customer wants)?

Integration testing

Integration testing (sometimes called Integration and Testing, abbreviated I&T) is the phase of software testing in which individual software modules are combined and tested as a group. It follows unit testing and precedes system testing.

unit testing

unit testing is a procedure used to validate that individual units of source code are working properly. A unit is the smallest testable part of an application. In procedural programming a unit may be an individual program, function, procedure, etc., while in object-oriented programming, the smallest unit is a method; which may belong to a base/super class, abstract class or derived/child class.

The spiral model

The spiral model, also known as the spiral lifecycle model, is a systems development lifecycle (SDLC) model used in information technology (IT). This model of development combines the features of the prototyping model and the waterfall model. The spiral model is favored for large, expensive, and complicated projects.

v model

v model is model in which testing is done prallelly with development.left side of v model ,reflect development input for the corresponding testing activities.