I'm looking at setting up an automated continuous integration plan for the OneIsABlog application and I came across a couple of Scott Hanselman articles today which touch on this topic:
http://www.hanselman.com/blog/NUnitUnitTestingOfASPNETPagesBaseClassesControlsAndOtherWidgetryUsingCassiniASPNETWebMatrixVisualStudioWebDeveloper.aspx
http://www.hanselman.com/blog/TestingCodeGeneratedCodeWithNUnitTemporaryFilesVoodooRubberBandsAndReflection.aspx
Scott is a smart guy so I'll be interested to play around with this methodology.