How to test Connexion / Flask app?

Question

I use Connexion for Flask to create a microservice. I would like to write tests for my application using py.test .

The pytest-flask document says to create a device in conftest.py that creates the application as follows:

conftest.py

 import pytest from api.main import create_app @pytest.fixture def app(): app = create_app() return app 

In my test, I use the client fixture as follows:

test_api.py

 def test_api_ping(client): res = client.get('/status') assert res.status == 200 

However, when py.test starts py.test , the following error message appears:

 ==================================== ERRORS ==================================== _______________________ ERROR at setup of test_api_ping ________________________ request = <SubRequest '_monkeypatch_response_class' for <Function 'test_api_ping'>> monkeypatch = <_pytest.monkeypatch.MonkeyPatch instance at 0x7f9f76b76518> @pytest.fixture(autouse=True) def _monkeypatch_response_class(request, monkeypatch): """Set custom response class before test suite and restore the original after. Custom response has `json` property to easily test JSON responses:: @app.route('/ping') def ping(): return jsonify(ping='pong') def test_json(client): res = client.get(url_for('ping')) assert res.json == {'ping': 'pong'} """ if 'app' not in request.fixturenames: return app = request.getfuncargvalue('app') monkeypatch.setattr(app, 'response_class', > _make_test_response_class(app.response_class)) E AttributeError: 'App' object has no attribute 'response_class' 

How can i make py.test work? Here is my create_app function:

main.py

 import connexion def create_app(): app = connexion.App(__name__, port=8002,) app.add_api('swagger.yaml') return app if __name__ == "__main__": create_app().run() 

Answer 1

Using fixtures

test_api.py

 import pytest import connexion flask_app = connexion.FlaskApp(__name__) flask_app.add_api('swagger.yml') @pytest.fixture(scope='module') def client(): with flask_app.app.test_client() as c: yield c def test_health(client): response = client.get('/health') assert response.status_code == 200 

swagger.yml

 swagger: '2.0' info: title: My API version: '1.0' consumes: - application/json produces: - application/json schemes: - https paths: /health: get: tags: [Health] operationId: api.health summary: Health Check responses: '200': description: Status message from server describing current health 

api.py

 def health(): return {'msg': 'ok'}, 200 

Using the Swagger Tester

Another solution using swagger-tester :

test_api.py

 from swagger_tester import swagger_test authorize_error = { 'get': { '/health': [200], } } def test_swagger(): swagger_test('swagger.yml', authorize_error=authorize_error) 

The cool thing about this library is that you can use the examples provided in your specification. But I don't think this works out of the box with connexion.RestyResolver : you need to specify an OperationId on each endpoint.