def test_entry(self):
selector = Selector(['uid', 'pid'])
self.assertEqual(list(selector.entry({'ol': 3, 'uid': 3})),
[('uid', 3)])
self.assertEqual(list(selector.entry({'pid': 's', 'uid': 3})),
[('uid', 3), ('pid', 's')])
self.assertEqual(list(selector.entry({'id': 's'})), [])
