One of the steps all good developers take when developing an application is unit testing.  Unit testing involves testing a single method or function to ensure it is behaving as expected.  From what I've seen through real life experience is that when a developer initially develops his or her method they thoroughly unit test it. However, when changes are made for a new release I've seen the process fall apart.  A lot of time developers make the change that was requested and only test the scenario that was requested without going back to make sure other scenarios didn't break.  I'm guilty of this myself.

Visual Studio has a great unit testing framework which can help solve this problem.  You can build  unit testing scripts, which are essentially classes that call your code that you can then execute to determine if you're code is working correctly.  When you make an enhancement or re-factor your code you can simply run the unit test scripts to determine that the code is still functioning properly. It will take you extra time to initially develop your code but it is worth the investment knowing that your code is working correctly and that you can more easily maintain your code with confidence.

This article will show you how to create an ASP.NET application and how to unit test the ASP.NET web page and a public class in a class project.  It will also demonstrate how to execute your unit tests individually or in a group. The code for this sample can be found here.