I've become a real fan of unit testing, though I was somewhat skeptical about its use in Web apps. NUnitASP is pretty cool for testing UI, but what I really needed was a way to test classes running in the context of a Web app, not actual requests for pages.
I do some caching voodoo in POP Forums to reduce database hits. Naturally this relies on the cache of the Web app, which you don't have in a unit testing context. Bummer! After some searching and link hopping I got to this article by Steve Padfield. Bam! That's what I needed. I only needed to make it work in .NET v2.
After some messing around, I arrived at this:
TextWritertw = new StringWriter();
HttpWorkerRequest wr = new SimpleWorkerRequest("/webapp", "c:\\inetpub\\wwwroot\\webapp\\", "default.aspx", "", tw);
HttpContext.Current = new HttpContext(wr);
Pop that code in any test that will call a class that needs a non-null HttpContext. Works like a champ, and life is grand. Now if I can only get the damn tests, or the assembly being tested, to see my config settings.