We all developing asp.net application using Microsoft.net and as a human being we all can't kept track of each and everything. We meant to have some error in our code. We call them bugs. Bugs can be removed via testing. Some time testing take more time then expected, so we have to use the automated testing tool to test your asp.net applications.
I have found a great automated testing framework for asp.net. It is a great thing which can do the test and find bugs.
NUnitASP is a tool for automatically testing ASP.NET web pages. It's an extension to NUnit, a tool for test-driven development in .NET.
Once you have an automated suite of tests, you'll never go back. It gives you incredible confidence in your code. That confidence allows you to code much faster, because you can make risky changes secure in the knowledge that your tests will catch any mistakes.
Here is the URL from which you can download the framework.