Agile and TDD

When we talk about TDD, Agile is most often discussed. Sometimes, people have doubts about whether Agile can exist without TDD or not. Well, of course it can, though. Agile and some people would say that TDD is Agile at a bigger scale. Through TDD, both show similar characteristics, but they are different. Agile is a process where testing is done as soon as a component is developed. It's not necessary in Agile to write test cases first and then perform development. But in the case of TDD, a test is always written first, and then its corresponding minimal production code.

TDD is about how code should be written while Agile is about the whole development process, not just code and its testing. Agile does not tell you how to build the system. Agile methodology is a management process, which can use TDD as an integral part.

Agile, when combined in practice with TDD, brings the best results. This combination minimizes risks, defects, cost, and results in a nearly zero-defect system.