title: Prefixing interfaces with I?
body: <p>I am currently reading "Clean Code" By Rober Martin (UncleBob), and generally loving the musings of UncleBob. However, I got a bit confused, when I read that he avoids prefixing interfaces like "IPerson". He states "I don't want my users knowing that I'm handing them an interface". </p>
  
  <p>Thinking in TDD/injection perspective, I will always be very interested in telling the "users" of my classes that I am handing on an interface. The primary reason is that I consider Interfaces contracts between the different "agents" of a system. An agent working with one corner of my system, should not know the concrete implementation of another agents work; they should only exchange contracts, and expect the contracts to be fulfilled without knowing how. The other, but also very important, reason is that an interface can be mocked fully, and thus making unit-testing much easier. There are limits to how much you can mock on a concrete class.   </p>
  
  <p>Therefore, I prefer to visualize that I am indeed handing on an interface... or taking an interface as argument. But since UncleBob is a heavyweight champ in our community, and I am just another flyweigth desk jockey, I would like to know if I am missing something. </p>
  
  <p>Is it wrong for me to insist on I's in interfaces??</p>