title: Unit Test project fails running v11 of BuildShadowTask
body: <p>I have a web application project I'm trying to migrate to .NET 4.5. We're building out of TFS to a build server with VS2010 installed, but that also contains all of the correct reference assemblies for VS2012 and has .NET 4.5 framework installed. </p>
  
  <p>When running a unit test project containing private accessors, the build fails with the error - </p>
  
  <pre><code>System.IO.FileNotFoundException: Could not load file or assembly 'file:///C:\LocalPath\Microsoft.VisualStudio.QualityTools.UnitTestFramework.dll'
  </code></pre>
  
  <p>However, the build will succeed if I change the $(MSBuildExtensionsPath)\Microsoft\VisualStudio\v11.0\TeamTest\Microsoft.TeamTest.Targets file from </p>
  
  <pre><code>&lt;UsingTask TaskName="BuildShadowTask" AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v11.0\TeamTest\Microsoft.VisualStudio.TestTools.BuildShadowsTask.dll"/&gt;
  </code></pre>
  
  <p>to</p>
  
  <pre><code>&lt;UsingTask TaskName="BuildShadowTask" AssemblyFile="$(MSBuildExtensionsPath)\Microsoft\VisualStudio\v10.0\TeamTest\Microsoft.VisualStudio.TestTools.BuildShadowsTask.dll"/&gt;
  </code></pre>
  
  <p>Is it no longer possible to use private accessors with VS2012? If so, why does Microsoft.VisualStudio.TestTools.BuildShadowsTask.dll v11 fail, but v10 succeed?</p>
  
  <p><strong>EDIT</strong> This will compile on a machine that actually has VS2012 installed, so it's gotta be the fact that I'm missing an assembly or registry key. Looking at the build logs, in both instances, it's loading BuildShadowTask from v11 folders. I guess my question changes to, is it possible to use private accessors without installing Visual Studio 2012? And if so, what change do I need to make to get this target to succeed?</p>