title: VS 2015: TF900547: The directory containing the assemblies for the Visual Studio Test Runner is not valid ''
body: <p>I Have VS 2015 only installed on my TFS 2013 build server, and get the following error:</p>
  
  <pre><code>TF900547: The directory containing the assemblies for the Visual Studio Test Runner is not valid ''.
  </code></pre>
  
  <p>Other sites say to install VS 2013, but why would I have to install VS 2013 on the build server to run unit tests when I have VS 2015 installed?</p>
  
  <p>I have the following switches on my build:</p>
  
  <pre><code>  /p:VisualStudioVersion=14.0  /tv:14.0
  </code></pre>
  
  <p>(This is not a duplicate question as I am using TFS 2013 and am trying to use the Agile Test Runner not MS Test)</p>