def test_fetch(self, mock_set, mock_get, mock_cached, mock_index):
cache = Cache('test')
mock_cached.return_value = True
cache.fetch('cached_key', 'source')
self.assertTrue(mock_get.called)
self.assertFalse(mock_set.called)
mock_get.reset_mock()
mock_set.reset_mock()
mock_cached.return_value = False
def source(): return 'value'
cache.fetch('uncached_key', source)
self.assertTrue(mock_get.called)
mock_set.assert_called_once_with(cache, 'uncached_key', source())
