The Validation, Verifiaction and Test model of software development management aims at integrating a testing methodolgy into a project develoment lifecycle. For a detailed project document see the VV&T Guidance document by Gerald Sharrock (600 KB Word Document)

A more specific version tailored to display only the testing stages of the model is shown in the following picture taken from Glenford Myer's The Art of Software Testing. In this version, an iterative process of development, verification and testing is carried out for each step in a software product development lifecycle.