compare/tests/org.eclipse.papyrus.compare.diagram.tests/src/org/eclipse/papyrus/compare/diagram/tests/modelextension/data/fileextension/fileextension.xml

<?xml version="1.0" encoding="UTF-8"?>
<?eclipse version="3.4"?>
<plugin>
   <extension
         point="org.eclipse.papyrus.infra.core.model">
      <model
            fileExtension="fileextensiontest">
      </model>
   </extension>
</plugin>