[test api] rename _user_session to user_groups_session, fix its arguments and return only the session, not (user, session) to make things clearer
"""cube-specific forms/views/actions/components
:organization: Logilab
:copyright: 2001-2010 LOGILAB S.A. (Paris, FRANCE), license is LGPL v2.
:contact: http://www.logilab.fr/ -- mailto:contact@logilab.fr
:license: GNU Lesser General Public License, v2.1 - http://www.gnu.org/licenses
"""