The gremlin-variant tests currently fail unless the aenum package has been installed and added to PYTHONPATH. I notice that the mavenjython plugin can download and install python packages (http://mavenjython.sourceforge.net/compile/) but when I add aenum to the plugin configuration, it still doesn't seem to be available to the tests. This could be because I'm not using maven properly.
If that's not applicable to this use case, to run the tests on travis, we could create a virtualenv, install aenum, and add it to the PYTHONPATH. This could be done by a shell script, run by travis before 'mvn clean install'.