Unit Test Your .NET Data Access Layer
Learn how to use NUnit and some related tools for successfully support testing a Data Access Layer for ASP.NET applications. Test driven development (TDD) has grown in popularity recently, especially with the growth of the Extreme Programming (XP) methodology. NUnit is a unit testing tool built for .NET, which follows in a long line of similar xUnit testing tools built for other platforms. It provides an easy-to-use framework for writing and running unit tests for your .NET applications.
Full article at the MSDN Library