It's really confusing to debug when functions/methods return more than one value type.  Either return a ``bool`` or an ``int`` but not both.  In this case, if the cgroup can't be read I think that should be a failure condition.  Perhaps check inside ``initialize()`` ``os.path.isdir(self.config['cgroup_path'])`` and toss a ``DockerTestNA("Configuration problem")`` if it's not setup.  Also, please include any setup needed for docker cgroups in the prerequisites section of docs for this test :D