ABSTRACT
In this chapter, we begin with various models of the software development life cycle in terms of the implications these life cycles have for testing. We took a general view in Chapter 1, where we identified three levels (unit, integration, and system) in terms of symmetries in the waterfall model of software development. This view has been relatively successful for decades, and these levels persist; however, the advent of alternative life cycle models mandates a deeper look at these views of testing. We begin with the traditional waterfall model, mostly because it is widely understood and is a reference framework for the more recent models. Then we look at derivatives of the waterfall model, and finally some mainline agile variations.
