Fix formatting of test files

tests/conftest.py

tests/integration/conftest.py

tests/integration/test_activity.py

tests/integration/test_albums.py

tests/integration/test_artists.py

tests/unit/conftest.py

tests/unit/test_model_activity_object.py

tests/unit/test_model_activity_related_object.py

tests/unit/test_model_album.py

tests/unit/test_model_api_mutation.py

tests/unit/test_model_artist_with_albums.py

tests/unit/test_model_attachment.py

tests/unit/test_model_channel.py

tests/unit/test_model_global_preference.py

tests/unit/test_model_global_preference_request.py

tests/unit/test_model_inbox_item.py

tests/unit/test_model_library.py

tests/unit/test_model_library_follow.py

tests/unit/test_model_library_follow_all.py

tests/unit/test_model_library_follow_request.py