'Call ``GET /regions?parent_region_id={parent_region_id}``.'

def test_list_regions_filtered_by_parent_region_id(self):

    new_region = self._create_region_with_parent_id()
    parent_id = new_region.result['region']['id']
    new_region = self._create_region_with_parent_id(parent_id)
    new_region = self._create_region_with_parent_id(parent_id)
    r = self.get(('/regions?parent_region_id=%s' % parent_id))
    for region in r.result['regions']:
        self.assertEqual(parent_id, region['parent_region_id'])
