title: Can't add Shared Project to Visual Studio Test Project
body: <p>I'm using Visual Studio 2015</p>
  
  <p>I have a Shared Project as an Independent Solution (A collection of Extensions used in several others Solutions).</p>
  
  <p>I want to TEST the Shared Project (Independently any other solution).</p>
  
  <p>So, I add a new TEST Project.</p>
  
  <p>But, in my TEST Project I can't add ANY reference to the Shared Project (No option).</p>
  
  <p><a href="https://i.stack.imgur.com/skV2D.png" rel="noreferrer"><img src="https://i.stack.imgur.com/skV2D.png" alt="enter image description here"></a></p>