by Njål

Unit testing – Visual Studio 2012 Fakes in Team City


TeamCity only supports the MsTest testrunner for running MS Tests. This testrunner does not support the brilliant Fakes Framework.


If you run the tests with MsTest – you’ll get the legendary ShimNotSupportedException – which you can read more about here.

The Visual Studio 2012 Test Runner however supports Fakes – here’s how to make Team City use this runner instead of MsTest:



“C:Program Files (x86)Microsoft Visual Studio 11.0Common7IDECommonExtensionsMicrosoftTestWindowvstest.console.exe” /inIsolation UnitTest.dll


Note that this requires Visual Studio 2012 on the Build Agent machine. I know a lot of you don’t like this – so you can also just copy the files in the TestWindow folder to your Build Agent and use vstest.console.exe directly.

Another thing which is nice is that the VSTest is a lot faster than MsTest.

by Njål

Visual Studio 2012 Fakes – ShimNotSupportedException when debugging tests



When testing VS2012 Ultimate I tried to use the new Microsoft Fakes framework to mock a simple static method. Running the test went fine, but I kept getting a ShimNotSupportedException when debugging the test. 

After goggling and trying all kinds of stuff I finally managed to debug the test by following these steps:

  1. Deleted the local.testsettings file (both in VS and on disk)

  2. Deleted the <solution>.vsmdi file (both in VS and on disk)
  3. Made sure IntelliTrace had these settings (not sure if this mattered):


  4. Restarted VS2012
  5. Made sure that no .testsettings file were selected here


Debugging of tests now works fine!
(Running/debugging the tests from Resharper still does not work – but I can live with this.)

I tried to add a new .testsettings file (with CodeAnalysis and everything else disabled) – but this makes the ShimNotSupportedException reappear again.

Similar Fakes/ShimNotSupportedException/Debug issues have been reported to MS, so I hope they get this resolved soon.


Another sad fact is that the Fakes framework is only available in the Ultimate edition of Visual Studio 2012 – which retails at over USD 13,000. This makes absolutely no sense at all. ALL developers should use unit testing as part of their tool belt – and isolating tests using a mocking framework plays a key role. Microsoft Moles could be used for free in the previous VS 2010 version – and it worked great. This is very disappointing.

Please vote for this issue here: