public void SetMediaElement () { MediaElement media = new MediaElement (); VideoBrush brush = new VideoBrush (); object retval; brush.SourceName = "iTube"; media.Name = "YouTube"; brush.SetSource (media); Assert.AreEqual (String.Empty, brush.SourceName, "SourceName after SetSource"); // since String.Empty is the default value, we also have to check RLV retval = brush.ReadLocalValue (VideoBrush.SourceNameProperty); Assert.AreNotEqual (DependencyProperty.UnsetValue, retval, "SourceName is not cleared after SetSource"); }