Employing a Test Driven Development (TDD) methodology when building a complex application may be tedious and take twice as much time, but the upshot is scalable stability as the tortoise beats the hare. As lead developers of Zurmo, an Open Source Customer Relationship Management (CRM) application, we are driven by the need to build rock solid, reliable software, something that is hard to come by in our field. In order to accomplish our goal, we decided to bite the bullet and sweat it out with Test Driven Development - TDD. Zurmo is written in PHP and utilizes jQuery, the Yii Framework, and RedBeanPHP. With 1700+ unit tests running across eight server configurations, Zurmo is built with a passion for software engineering best practices. Read the article to find out why it is beneficial to be in the habit of testing, testing, and more testing.