TDD proponents claim that it results in better design and decoupled objects. I can understand that writing tests first enforces the use of things like dependency injection, resulting in loosely coupled objects. However, TDD is based on unit tests - which test individual methods and not the integration between objects. And yet, TDD expects design to evolve from the tests themselves.

So how can TDD possibly result in a better design at the integration (i.e. inter-object) level when the granularity it addresses is finer than that (individual methods)?