Test-Driven Development

Test-driven development (TDD) is a software development approach using a growing scaffold of tests that guide and support the production of code. This entry describes TDD, explains the underlying dynamics, provides a small worked example, and offers a theory of how and why it works. It relates TDD to other approaches that employ a similar style of development and presents a summary of the empirical results about TDD’s effectiveness. The entry also raises some of the known concerns and challenges about this development practice and provides pointers to solutions. TDD is a practice that has widespread impact on the software development lifecycle. Adopting it takes a great amount of discipline. However, we cannot say whether TDD is right for everyone and for all types of software: this entry should help the reader decide whether to explore further.