This document discusses testing JavaScript applications using behavior-driven development (BDD). BDD involves first describing behaviors using human-readable sentences, then building code to implement those behaviors, and repeating the process. Examples of behavior statements are provided, such as taking a user to their account page when they click "my account" if logged in. The document recommends writing tests to extend features, add complexity, debug issues, and collaborate with others. It promotes practicing writing tests and integrating them into the development process.