When you use the Unit Testing feature for Schemas and Maps in a Microsoft BizTalk Server 2013 project, the unit test for Maps does not work. Additionally, you receive the following error message:
This issue occurs because the TestableMapBase class is not upgraded in BizTalk Server 2013. In this case, the BTSXsTransform class is still being used instead of the XslCompiledTransform class.
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.