We have a directory gwtutil with 10+ classes in there, which we want to delete from the archive

This does nothing, it does not even fail-fast:

webArchive.delete(ArchivePaths.create("WEB-INF/classes/org/drools/guvnor/gwtutil/"));

This does work:

webArchive.delete(ArchivePaths.create("WEB-INF/classes/org/drools/guvnor/gwtutil"));

The difference is the absence of the trailing /.

Using arquillian bom CR5