Testing OAuth in controllers

I'm using the Google calendar API. This particular way I'm using requires OAuth, and to be honest I'm not that familiar with it. But I am trying work on my TDD. What are the best ways to test OAuth interactions?

If I simply make an http request: http://ift.tt/1995sls?

I get this JSON back form Google's api:

{
 "error": {
  "errors": [
   {
    "domain": "global",
    "reason": "required",
    "message": "Login Required",
    "locationType": "header",
    "location": "Authorization"
   }
  ],
  "code": 401,
  "message": "Login Required"
 }
}

This totally makes sense because I have authorized who's calendars I'm getting back. I can handle this in code just fine. But mocking it out in a controller test I can't seem to figure out how to do that.

All this being said. I'm not looking for an answer because I understand that this question is a bit vague. I'm simply looking to be pointed towards some good blog posts or best practices when it comes to mocking OAuth. Thanks for your help!