I've just learned how to use pytest for tests in Django/DRF-projects and successfully implemented a bunch of test functions. But, though they work OK, they work pretty slowly; and, for the sake of increasing their work speed, as well as for my personal educational and "sport" interest, I decided to try to implement them asynchronously. For that sake, I have found pytest-asyncio package. While I used pytest-asyncio the way it was described in its docs, when trying to activate tests they returned me an error (django.core.exceptions.SynchronousOnlyOperation: You cannot call this from an async context - use a thread or sync_to_async). I've read about this error and learned that Django ORM operations block the event loop and thus they have to operate via some workaround (threading or asgiref.sync_to_async). While I faced this error connected not only with Django ORM operations, but also with my response request methods (get/post), still I've tried to write this workaround and looked whether the reaction would have changed. It hasn't changed. And now nothing I have googled and read through helps me. The testing module tests downloading image files functionality and is set with API client and user (the first one has authorised and non-authorised versions). I'll mention here only one test of the whole bunch. @pytest_asyncio.fixture(loop_scope="module") async def current_loop(): yield asyncio.get_running_loop() @pytest.mark.django_db @pytest.fixture async def user() -> User: """ Creating test user """ yield User.objects.create_superuser(username='test.user', password='user.password') @pytest.mark.django_db @pytest_asyncio.fixture async def auth_client(user: User) -> Iterator[APIClient]: """ Authorised client session """ client = await sync_to_async(APIClient())() await sync_to_async(client.force_login(user))() yield client @pytest.mark.django_db @pytest_asyncio.fixture async def non_auth_client(user: User) -> Iterator[APIClient]: """ Non-authorised client """ client = await sync_to_async(APIClient())() yield client @pytest_asyncio.fixture async def model(current_loop): model_case = await sync_to_async(document_models.LicensesAndCertificatesImages)() yield model_case # teardown for model_object in model_case.objects.all(): model_object.delete() @pytest_asyncio.fixture async def post_url(): post_url_case = reverse('admin_site:documents_licenses-upload') yield post_url_case @pytest_asyncio.fixture async def get_list_url(): get_list_url_case = reverse('admin_site:documents_licenses-list') return get_list_url_case @pytest.mark.django_db @pytest_asyncio.fixture async def prepare_models_objects(user, model): """ Filling DB with model objects for GET-requests testing """ uploaded_by = await sync_to_async(get_user_model().objects.first())() for i in range(5): file = SimpleUploadedFile( name=f'file_{i}.png', content=b'correct_file_content', content_type='image/png', ) await model.objects.create(document=file, uploaded_by=uploaded_by) yield """ Tests """ @pytest.mark.django_db async def test_get_list(prepare_models_objects, model, auth_client, get_list_url): """ Check if GET-request receives License and Sertificates list """ response: Response = await sync_to_async(auth_client.get(path=get_list_url))() assert response.status_code == 200 assert len(response.data) == 5 assert list(response.data[0].keys()) == ['id', 'document'] After pytest activation command every test returns me django.core.exceptions.SynchronousOnlyOperation: You cannot call this from an async context - use a thread or sync_to_async. In sync-version the test works well (meaning that all other tests and fixtures are also in their sync-versions): @pytest.mark.django_db def test_get_list(prepare_models_objects, model, auth_client, get_list_url): response: Response = auth_client.get(path=get_list_url) assert response.status_code == 200 assert len(response.data) == 5 assert list(response.data[0].keys()) == ['id', 'document'] Can someone explain me what I am doing wrong? Continue reading...
