Given When Then

Given, When, Then is a style of writing scenarios, borrowed from BDD tools like Cucumber.

Here is an example of the usage in Cucumber describing a scenario for a web application that works with movies:

Scenario: List the movies
   Given I have the movies "Blazing Saddles" and "Young Frankenstein"
   When  I go to "list movies" page
   Then  I should see "Blazing Saddles" and "Young Frankenstein" in the listing

When applied to unit tests, if you are familiar with the AAA style (Arrange, Act, Assert) GWT is very similar:

• Given = Arrange
• Act = When
• Assert = Then

Though I like AAA, I wanted a way to enforce how the scenarios should be written, that's why the MT Testing library enforces GWT syntax.

Because each framework usually has hooks before and after all the tests is very easy to implement the GWT syntax and call the Given and When methods. Here is a simplified version of the code to show how it's done:

        protected override void BeforeEachTest()
        {
            this.GivenThat();

            this.WhenIRun();
        }