title: Assembly conflict resolution for Microsoft.Data.Tools.Schema.Sql.UnitTesting assembly
body: <p>I have a database unit test project from VS 2015. I am now testing VS 2017 RC.</p>
  
  <p>There is an assembly conflict with the <code>Microsoft.Data.Tools.Schema.Sql.UnitTesting</code> assembly that I am not sure how to resolve. The GAC has version 15.0 of this assembly. As part of VS 2017 SSDT, version 15.1 is available, but not in the GAC.</p>
  
  <p>I've tried assembly redirection in app.config, but that did not make a difference.</p>
  
  <p>I've tried specifically browsing to the <code>C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Common7\IDE\Extensions\Microsoft\SQLDB</code> folder and selecting the assembly there as a reference. However, it reverted to the GAC assembly. It kept doing that even as I set Specific Version = True in project properties.</p>
  
  <p>I've already removed the old folder with SSDT from the Reference Paths project property and pointed it to the 2017 location.</p>
  
  <p>I had a similar problem with the Microsoft.Data.Tools.Components assembly, but it was resolved by specifying Specific Version = False (oddly enough...) in the project properties.</p>
  
  <p>If I remove the reference from the project, the project builds but warns that version 15.0 of the assembly cannot be found. In that case, the tests even run and pass. That only lasts as long as the solution is open though. Once I close and reopen it, "bad" references re-appear in the References list.</p>
  
  <p><a href="https://i.stack.imgur.com/vC5Kn.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/vC5Kn.png" alt="Screen shot of References list of database project after loading"></a></p>
  
  <p><strong>EDIT</strong>: I have run asmspy and it detects some conflicts between 2.0 and 4.0 versions of system assemblies, including mscorlib and System.Data. The 2.0 versions are all referenced by <code>Microsoft.VisualStudio.QualityTools.UnitTestFramework</code> version 10.0. I upgraded those references to 10.1 but that version still references version 2.0 of those assemblies. I don't know if this is related/relevant.</p>