title: Cannot Associate Test Case in Visual Studio
body: <p>I have a standard MSTest unit test in a unit test C# project file.  The project is running .NET Framework 4.7.2, and has version 1.3.2 of the MSTest adapter and framework installed.  I am running Visual Studio 2017 Enterprise 15.7.6, and have a VSTS workspace with some random manually-created test cases in it.</p>
  
  <p>When I right-click on my unit test in the Test Explorer, and select "Associate to Test Case", I am able to enter the test case ID, add the association, and click "Save".  Upon save, I get an error message, below.</p>
  
  <p><a href="https://i.stack.imgur.com/CV0Lb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/CV0Lb.png" alt="Method not found: &#39;System. Threading. Tasks. Task&#39;l &lt;Microsoft. Team foundation. Worldte mTraclcing.WebAptModels.Worldtem&gt; Microsoft. Teamfoundation.Workltem Tracking.WebApi.Workltem Tra ckingHttpCiientBase.UpdateWorkltemAsync (Microsoft.VisuaiStudio.SeiVices.WebApi.PatchJson.JsonPatchDocu men!, lnt32, System.Nullable&#39;1 &lt;Boolean&gt;, System.Nullable&#39;1 &lt;Boolean &gt;, System.Nullable&#39;1 &lt;Boolean&gt;, System.Object, System.Threadi ng.Cancellation Token)&#39;."></a></p>
  
  <p>I have tried to save the association using different versions of MSTest, and different .NET Framework versions for the project file, neither of which solved the issue.  I also tried running Visual Studio as an administrator, which did not work.  Has anyone else had this issue, or know of any workarounds?</p>