I've been researching unit testing for ASP.Net, particularly for a library of custom controls I created.  It was one of my first projects that could use some significant refactoring and receives frequent requests for new functionality.  I've discovered three primary open source unit testing tools for .NET:

Eric Gunnerson's blog has quite a discussion on the topic.  While digging through it, I discovered links to Phil Haak's articles on a lightweight HttpContext object and custom attributes for NUnit 2.2.1+.  In the first one, he references an article by Scott Hanselman describing how to use the Cassini web server and NUnit to test ASP.Net web pages.

It looks like I'll create a similar class to what Hanselman suggests as a base class to start my tests from.  It won't help me avoid searching the string for certain requirements, but will be a good starting point.  Thanks for the help, guys.