Kent Beck, who is credited with having developed or 'rediscovered'[1] the technique, stated in 2003 that TDD encourages simple designs and inspires confidence.[2]
Test-driven development is related to the test-first programming concepts of extreme programming, begun in 1999,[3] but more recently has created more general interest in its own right.[4]
Programmers also apply the concept to improving and debugging legacy code developed with older techniques.[5]