Forms and patterns

There are different forms, or styles, to write tests. Give/when/then (GWT) is once. Arrange/act/assert is another. And so on.

Given When Then

This patterns uses specification by example way to define tests. In this case the system is specified by example. This is a style of representing test developed as part of Behavioral Driven Development by Dan North. A lot of frameworks uses this approach. "Given" is used to define the initial context of the system. The purpose of Given phase is to put user in a known state before the user start interacting to the system. "When" is used to define the behavior we need to run. Finally, the "Then" part contains changes occurred.

Four-Phase Test

The pattern GWT is also described as Four-Phase Test (FPT). The four phase attach to the pattern the teardown step. The teardown step is not mandatory and not always useful because it does not improve the communication aspect of tests.