Unit Test is often used as a generic term to describe testing code-behind pages when it comes to Web Applications. Performing tests at the presentation tier can be cumbersome and usually involves manual case by case test scenarios in some large excel spreadsheets or a form of some sort.
The ASP.NET QA team have introduced Lightweight Test Automation Framework as a way to automate these regression test tasks. Your web browser is used as a test harness and your test cases are shown on the left pane of the webpage with realtime tests running on your web application shown on the right hand side.
Download LTF here: http://aspnet.codeplex.com/Release/ProjectReleases.aspx?ReleaseId=25887 (April09 release)
More Info:
http://weblogs.asp.net/asptest/
http://blog.hmobius.com/ Dan Maharry