I'm not sure I follow the argument. Use fakes instead of mocks, but if you change the dep1 to have a method add instead of addone, you still need to update the

I'm not sure I follow the argument. Use fakes instead of mocks, but if you change the dep1 to have a method add instead of addone, you still need to update the fake. The effect is the same as if you needed to update the mock setup. About the only benefit I can see, is if the fake is used in multiple tests and you only need to update it once.