title: How to unit test string extension method
body: <p>I have a bit of code as follows which I would like to unit test which is an extension method on the string class:</p>
  
  <pre><code>public static string Replace(this string str, Dictionary&lt;string, string&gt; dict)
  {            
  }
  </code></pre>
  
  <p>My extension method is in the main project so my unit test project can't even see it.</p>
  
  <p>How can I do this? I am using Nunit.</p>