self = <swh.storage.tests.test_cassandra.TestCassandraStorage object at 0x7f64e40cc5c0> swh_storage_backend_config = {'cls': 'cassandra', 'hosts': ['127.0.0.1'], 'journal_writer': {'cls': 'memory'}, 'keyspace': '14ac6b2ad10e704a4686', ...} def test_types(self, swh_storage_backend_config): """Checks all methods of StorageInterface are implemented by this backend, and that they have the same signature.""" # Create an instance of the protocol (which cannot be instantiated # directly, so this creates a subclass, then instantiates it) interface = type("_", (StorageInterface,), {})() storage = get_storage(**swh_storage_backend_config) assert "content_add" in dir(interface) missing_methods = [] for meth_name in dir(interface): if meth_name.startswith("_"): continue interface_meth = getattr(interface, meth_name) try: concrete_meth = getattr(storage, meth_name) except AttributeError: if not getattr(interface_meth, "deprecated_endpoint", False): # The backend is missing a (non-deprecated) endpoint missing_methods.append(meth_name) continue expected_signature = inspect.signature(interface_meth) actual_signature = inspect.signature(concrete_meth) > assert expected_signature == actual_signature, meth_name E AssertionError: snapshot_count_branches E assert <Signature (s...t], NoneType]> == <Signature (s...t], NoneType]> E +<Signature (snapshot_id: bytes) -> Union[Dict[Union[str, NoneType], int], NoneType]> E -<Signature (snapshot_id: bytes) -> Union[Dict[str, int], NoneType]> .tox/py3/lib/python3.7/site-packages/swh/storage/tests/test_storage.py:170: AssertionError