The document discusses test-driven development (TDD) and behavior-driven development (BDD). It explains that BDD uses external specifications to describe behavior before coding starts. This solves issues with TDD like where to begin and what to test. BDD uses a double cycle of writing scenarios in Behat and then examples in Phpspec at the internal class level. Phpspec is used to describe behavior through examples before coding classes. The document provides instructions on installing Phpspec and describes how to define a specification and examples.