Creating repeatable tests for BizTalk maps is frustrating. I can't find a way to handle testing them like I'd do unit testing, because I can't find ways to break them into logical chunks. They tend to be one big monolithic unit, and any change has the potential to ripple through the map and break a lot of unit tests. Even if I could break it up, creating XML test inputs is painful and error prone.

Is there any effective way of testing these? I'd settle for recommendations for testing XSL transforms in general, but I specifically mention BizTalk maps primarily for the reason that when using the mapper, there really isn't any way to break your XSLT into templates (which I'd imagine you could use to break up your logic into testable chunks, but I've honestly never gotten that far with XSLT).