Jeff Wilcox, primary developer of the Silverlight unit test framework, has posted several entries on writing unit tests for Silverlight 2. In addition to step-by-step instructions, Jeff has provided updated test project templates and repackaged Silverlight.Testing assemblies. The updated test framework allows testing against Microsoft's recently released Beta 2 of its upcoming Silverlight 2.0 rich-client browser plugin. The current Silverlight testing framework is not yet integrated into the Visual Studio test runner, but the framework leverages the same types and attributes used by MS Test and should be familiar to developers who are writing traditional unit tests in Visual Studio. Even if a development team does not practice test-driven development, having programmatic tests exercise UI code is valuable for regression and integration testing.
Jeff sums up the value in his tutorial:
Having unit tests is extremely useful because the more test scenarios you create, the more confidence you'll have when adding features and fixing bugs, especially if you're working with a team of developers. Since the test projects are packaged like any other Silverlight application, there's no special installation process to run the tests. On the Silverlight controls team we've built thousands of these tests!