Got the mysterious error “Missing attribute test”.
Finally, noticed that I had the “t” missing on the keyword “test”:

<xsl:if est=”RateAndCharges/@SpecialChargeOrAllowanceCode != ‘ABC’ “>

<xsl:if test=”RateAndCharges/@SpecialChargeOrAllowanceCode != ‘ABC’ “>

This error can occur when you use a map that is XSLT based. It is possible to compile and deploy the project, even when the XSLT is malformed or has errors in it.

Try the following:
1) Open your project in Visual Studio, and do a test map with some real incoming data.
2) Make sure you XSLT is well-formed XML.