self = <swh.storage.tests.test_in_memory.TestInMemoryStorage object at 0x7fd1023fdbe0> swh_storage_backend_config = {'cls': 'memory', 'journal_writer': {'cls': 'memory'}} 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) .tox/py3/lib/python3.7/site-packages/swh/storage/tests/storage_tests.py:155: _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ /usr/lib/python3.7/inspect.py:3083: in signature return Signature.from_callable(obj, follow_wrapped=follow_wrapped) /usr/lib/python3.7/inspect.py:2833: in from_callable follow_wrapper_chains=follow_wrapped) _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ obj = None def _signature_from_callable(obj, *, follow_wrapper_chains=True, skip_bound_arg=True, sigcls): """Private helper function to get signature for arbitrary callable objects. """ if not callable(obj): > raise TypeError('{!r} is not a callable object'.format(obj)) E TypeError: None is not a callable object /usr/lib/python3.7/inspect.py:2208: TypeError