[sorokod]

TDD is obviously a hill climbing strategy as far as the end result is concerned and the outcome has the associated baggage.

"Refactor" is named this way to emphasize that changes you are making are closely related to the tests you already have and the tests you are about to introduce.

That does not leave enough space to justify a QED. If you choose to design beyond that, the process stops being TDD - at least as described by Kent Beck