WebAii (http://www.artoftest.com/) is a free, though not open source test framework for testing web applications. Like Watir/Watin/Watij, it works by driving the browser, either IE or Firefox. Like Watin, it allows writing your tests in C#. It can be run under NUnit, Visual Studio Team Test, or your own application.
Set things up similarly to that described in VisualStudioCheatSheet.
Add the ArtOfTest WebAii .dlls to the project references.
Extend BaseNUnitTest for your test fixture. This gives you some convenience methods.
Oops! According to [http://www.artoftest.com/Resources/WebAii/Documentation/topicsindex.aspx?topic=usingnunit the docs] a template should be installed to do this for you. I didn't find that to be true--perhaps it's because I'm running the 'Express' edition of Visual Studio.
Call Initialize() at the start of your test or in the SetUp method. This is part of BaseNUnitTest and does all the work of initializing the Manager.
Call Manager.LaunchNewBrowser() to prepare a browser that your test will use to execute your tests.
Oops! This isn't working for me. It launches the browser, but never "connects." I'm not yet sure if this is connecting the test runner to the browser instance, or something else. Instead, it waits for 60 seconds (the default timeout) before reporting the error.
... More stuff goes here, once the above problem is resolved.
Call this.CleanUp() at the end of your test or in the TearDown method. This is part of BaseNUnitTest and releases all of the resources allocated during Initialize().
ToBeWritten ...