Lately I have been researching BDD.  What I have discovered so far, is that BDD is about joining Test Driven Development and Domain Driven Design agile methods together.  TDD starts with creating unit tests for code that will be developed, and not code that has already been developed.  Then as the developer acquires a better understanding of TDD, this agile method becomes more valuable.  What happens next is that TDD becomes a tool to help focus on the needed code.  The tests that are created help with the understanding of the program when the developer comes back to it six months later.  So by creating the test first, the developer can gain a quicker understanding of the required behavior.  By using an unambiguous language, we help ourselves with the understanding of the behavior.

With TDD, xunit frameworks are required to develop the test.  With BDD something like NSpec is needed.

Agile