This document discusses test-driven development (TDD) using Karma and Jasmine tools. It covers what TDD is, why it is used, how to implement TDD, and includes a code demo. TDD involves writing failing automated tests before code to verify functionality, producing just enough code to pass each test. Using TDD enhances code maintainability and provides immediate feedback on changes. The document reviews tools like Karma and Jasmine for JavaScript testing and how to set up specs, matchers, dependencies and async support for TDD.