Test Driven Development: By Example

Chapter 28. Green Bar Patterns

Once you have a broken test, you need to fix it. If you treat a red bar as a condition to be fixed as quickly as possible, then you will discover that you can get to green quickly. Use these patterns to make the code pass (even if the result isn't something you want to live with for even an hour).

Fake It ('Til You Make It)

What is your first implementation once you have a broken test? Return a constant. Once you have the test running, gradually transform the constant into an expression using variables.

A simple example occurred in our implementation of xUnit:

						return "1 run, 0 failed"
					

became:

						return "%d run, 0 failed" % self.runCount
					

became:

						return "%d run, %d failed" % (self.runCount , self failureCount) ...