Add session attribute to Group/User/Page/Thread

tests/conftest.py

@@ -6,6 +6,11 @@ from contextlib import contextmanager
 from fbchat import ThreadType, Message, Mention
 
 
+@pytest.fixture(scope="session")
+def session():
+    return object()  # TODO: Add a mocked session
+
+
 @pytest.fixture(scope="session")
 def user(client2):
     return {"id": client2.id, "type": ThreadType.USER}