swh_storage = <swh.storage.retry.RetryingProxyStorage object at 0x7fdf05181a90> sample_data = <swh.storage.tests.storage_data.StorageData object at 0x7fdf05181208> mocker = <pytest_mock.plugin.MockFixture object at 0x7fdf05181048> def test_retrying_proxy_swh_storage_directory_add_failure( swh_storage, sample_data, mocker ): """Unfiltered errors are raising without retry """ mock_memory = mocker.patch("swh.storage.in_memory.InMemoryStorage.directory_add") mock_memory.side_effect = StorageArgumentException( "Refuse to add directory always!" ) sample_dir = sample_data.directory > directory_id = swh_storage.directory_get_random() # no directory .tox/py3/lib/python3.7/site-packages/swh/storage/tests/test_retry.py:620: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ .tox/py3/lib/python3.7/site-packages/swh/storage/in_memory.py:458: in directory_get_random return random.choice(list(self._directories)) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ self = <random.Random object at 0x1946b28>, seq = [] def choice(self, seq): """Choose a random element from a non-empty sequence.""" try: i = self._randbelow(len(seq)) except ValueError: > raise IndexError('Cannot choose from an empty sequence') from None E IndexError: Cannot choose from an empty sequence /usr/lib/python3.7/random.py:261: IndexError