> I thought the whole point of TDD as opposed to just “writing a lot of tests” is that you write the tests first, and that more or less determines the design of

> I thought the whole point of TDD as opposed to just “writing a lot of tests” is that you write the tests first, and that more or less determines the design of the system? Yes, my thoughts exactly. At its core, TDD forces a workflow where the interface is the first thing laid out, and the expected behavior follows. Therefore when designing new components, it becomes readily apparent when the interface doesn't work, even before anyone invests any time adding the missing behavior.