If the one intend to run a WPF test using ArtOfTest.Runner.exe and using environment variables for path to the application and to the test - it has to be done when default path to the application is not set. If it is set the ArtOfTest.Runner will trow an exception. For example: ArtOfTest.Runner.exe test="%TEST_PATH%\WPFTest.tstest" root="%TEST_PATH%"