The same that that structural test creates unnecessary coupling there will be other tests that create that coupling as well. It is a learning phase. You will realize that there are things that you can do and things that you can't do while testing.

Once I learned how to test properly, TDD has been helpful, never a hindrance.

In case you haven't read them `Test Driven Development By Example` by Kent Beck and `Growing Object-Oriented Software Guided by Tests` by Steve Freeman and Nat Pryce are great books