The directory containing the assemblies for the Visual Studio Test Runner is not valid

Question

We have upgraded our TFS installation from 2012 to 2013. When running our builds they will fail with the following error if unit tests are enabled:

TF900547: The directory containing the assemblies for the Visual Studio Test Runner 
          is not valid ''

The build process template or build definitions has not been changed after the upgrade. The upgrade process did not change them. Where can I provide the path to the Visual Studio Test Runner and where is it located on disk?

I do not know if "Visual Studio Test Runner" is a new option for 2013 or if this setting was also used before, when we were using TFS 2012.

We use Visual Studio Professional 2012 on the build server.

Answer 1

To do the second choice in Oswald's answer:

1. Right click on your build definition and select "Edit Build Definition..."
2. Click on the "Process" group in the build definition.
3. Find the "Automated Tests" group under "Build Process Parameters" and click on the ellipsis.
4. A "Automated Tests" dialog box will appear, select the test under "Tests to run" that you want to edit.
5. Click on the "Edit", a "Add/Edit Test Run" dialog box will appear.
6. Change the test runner to "MSTest.exe test runner"

Note: I am using TFS2012