Bob Martin’s Three Laws of TDD

Bob Martin describes Test-Driven Development using these three simple rules:

1. Do not write production code unless it is to make a failing unit test pass.
2. Do not write more of a unit test than is sufficient to fail, and build failures are failures.
3. Do not write more production code than is sufficient to pass the one failing unit test.

Even though this sounds restrictive, it is a very productive and fun way to develop software.

Fonte: http://butunclebob.com/ArticleS.UncleBob.TheThreeRulesOfTdd