A little while ago while I was one of the industry advisors for the PAG group at Microsoft. One of the last things I did in that capacity was provide input to the the Testing App blocks for MS. Microsoft has finally released this and can be downloaded here.
Testing .NET Application Blocks covers many testing areas that were used during testing and verification of the various application blocks provided by Microsoft’s patterns & practices group, such as functional, globalization, performance, integration, and security. The guide uses code examples, sample test cases, and checklists to demonstrate how to plan and implement each type of test; the guide also recommends tools to use to run the tests. It covers test considerations to be taken into account when customizing these application blocks or integrating them with your own applications.
Because this guide focuses on testing NET application blocks, its scope does not include user interface (UI) testing or database testing. Although the guidance is developed within the context of Microsoft patterns & practices application blocks, it still applies to testing .NET code in general.