20.9. Test-Driven or Test-First Development
An excellent practice promoted by the Extreme Programming (XP) method [Beck00], and applicable to the UP and other iterative methods (as most XP practices are), is test-driven development (TDD) or test-first development . In this practice, unit testing code is written before the code to be tested, and the developer writes unit testing code for all production code. The basic rhythm is to write a little test code, then write a little production code, make it pass the test, then write some more test code, and so forth. This is explore in more detail in a following chapter.386