Assume that you use the Microsoft.BizTalk.TestTools.Mapper.TestableMapBase class in a Microsoft BizTalk Server 2013 R2 project in Microsoft Visual Studio 2013 to test maps. You are testing a map that uses a flat file destination schema. So, you set the OutputInstanceType to Native:
InputInstanceType inputType = InputInstanceType.Xml;
OutputInstanceType outputType = OutputInstanceType.Native;
target.TestMap(inputFile, inputType, outputFile, outputType);
In this situation, BizTalk.TestableMapBase.TestMap fails, and you encounter a BizTalkTestAssertFailException error and the message "Generate schema instance failure."
Cumulative update information
This issue was first fixed in the following cumulative update of BizTalk Server:
Microsoft has confirmed that this is a problem in the Microsoft products that are listed in the "Applies to" section.
For information about the service packs and cumulative update list for BizTalk Server, see KB 2555976: Service pack and cumulative update list for BizTalk Server.
For more information about BizTalk Server hotfixes, see KB 2003907: Information about BizTalk hotfixes and Service Pack support.