Test-Driven Design, Part 1
Most developers think that the most beneficial part of using test-driven development (TDD) are the tests. But, when done right, TDD improves the overall design of your code. This installment in the Evolutionary architecture and emergent design series walks through an extended example showing how design can emerge from the concerns that float up from testing. Testing is only a side effect of TDD; the important part is how it changes your code for the better.