What Do We Know about Test-Driven Development?

What if someone argued that one of your basic conceptions about how to develop software was misguided? What would it take to change your mind? That\´s essentially the dilemma faced by advocates of test-driven development (TDD). The TDD paradigm argues that the basic cycle of developing code and then testing it to make sure it does what it\´s supposed to do-something drilled into most of us from the time we began learning software development- isn\´t the most effective approach. TDD replaces the traditional "code then test" cycle. First, you develop test cases for a small increment of functionality; then you write code that makes those tests run correctly. After each increment, you refactor the code to maintain code quality.