Is my test structure too coupled to system structure?

[farlee2121]

http://blog.cleancoder.com/uncle-bob/2017/03/03/TDD-Harms-Architecture.html

[farlee2121]

One way this could manifest is testing against interfaces instead of concrete classes. Because of data prep abstraction, I can make my tests about the expected behavior of any instance of a service instead of for a concrete implementation.

[farlee2121]

If I test at too high a level, then the tests loose value as a construction aid.

At the very minimum, I'd want to test all of my services, since those are the unit of information hiding