Found a great resource today for how to go about testing BizTalk applications. It covers best practices on how to unit test various BizTalk artifacts such as schemas, maps, pipelines, orchestrations. This covers how these should be covered with tests for integration testing as well as functional testing. Very interesting read.
http://geekswithblogs.net/michaelstephenson/archive/2008/04/27/121687.aspx
