Xml Validation Interoperability Framework (xvif) is a proposal to embed pipe definitions in grammar based schema languages such as Relax NG (and probably W3C XML Schema). The current implementation is built on a partial implementation of Relax NG, supporting the features needed to provide a representative proof of concept. It is available both as Python source code and as an online demonstration. Although there is no endorsement of any kind by the DSDL ISO initiative (http://dsdl.org), one of the goals of this prototype is to gather feedback which may be used (or not) by "DSDL Part 1 - Interoperability Framework".
XSLTUnit is a test unit framework for XSLT, itself implemented as a XSLT transformation. With XSLTUnit, developers can easily perform unit tests on each of their XSLT templates (named or not). The home page includes the documentation and a link to "xsltunit.xsl", which is the actual implementation.