Today i was taking session of developer group and talking about the Visual Studio 2013 Test tools. Well it seems they did tried using it and bumped into error("Test host process exited unexpectedly - Failed to queue test run: Unable to start the agent process") on first trial.
Well It was a easy fix. As the user was running 64 bit processor based VM, he was geeting an error as Test project setting were set to 32 bit. Just change the test project settings.
Test-> Test Settings->Default processor Architecture ->Select x64