'Call ``PATCH /regions/{region_id}``.'

def test_update_region_without_description_keeps_original(self):

    region_ref = unit.new_region_ref()
    resp = self.post('/regions', body={'region': region_ref})
    region_updates = {'parent_region_id': self.region_id}
    resp = self.patch(('/regions/%s' % region_ref['id']), body={'region': region_updates})
    self.assertEqual(region_ref['description'], resp.result['region']['description'])
