Deployment is currently disabled error when testing BizTalk maps from VS2010

When writing unit tests to test your BizTalk maps from within Visual Studio, you mat sometimes get the following error: Deployment is currently disabled. DeploymentItem "_" on test "_" was not deployed



To fix this error, double-click on the 'local.testsettings' file in your solution



Click on the 'Deployment' tab on the left pane, and click on the 'Enable Deployment' tick box

The tests should run as expected now