Red – Green – Refactor
The xUnit and %UnitTest test reporting GUIs report passed tests in green and failed tests in red. The following is, then, the rhythm of development using the test first approach to development:
Red — Write a little test that doesn't work, and perhaps doesn't compile at first.
Green — Make the test work quickly, committing whatever sins necessary in the process.
Refactor — Eliminate all duplication created in merely getting the test to work.
— Kent Beck, Test Driven Design By Example