Application Testing

Question

Is the real benefit in TDD the actual testing of the application, or the benefits that writing a testable application brings to the table? I ask because I feel too often the conversation revolves so much around testing, and not the total benefits package.

Answer 1

TDD helps you design your software. The tests becomes the design. By writing the test first you think about your code from a consumer perspective, making a more user friendly and more compact software design.

Also, by applying TDD you typically end up writing your code in a way where you can supply test mocks and stubs. This leads to less coupled software, making it easier to change and maintain over time.

So I guess allot of the talk around TDD is about testing, but by doing that other big benefits follow, such as quality (coverage), flexibility (decoupling), better design (think as the consumer of the API).

Answer 2

The real improvement is that it is a good way to force you to really think through the design and implementation. Then, once you've prepared the tests and written the code, solutions to unforeseen problems appear more easily.

Something that usually happens to me that is a good analogy: When I'm going to post a question to a forum or IRC channel, I like to have the problems well written and fully described, many times the process of preparing a well written and complete description of the problem magically makes the solution appear.