struggling to test flask-dance / flask-security / flask-sqlalchemy / pytest

Question

My application requires login to google for later use of google apis. I have flask-dance, flask-security, flask-sqlalchemy working to the point where I can do the log in and log out in my development system.

What I've been struggling with is testing of the login using pytest. I am trying force the login with the call to flask_security.login_user, but test_login fails as if nobody is logged in. I suspect this is a problem because of context setting, but I have tried a lot of different things and haven't found the magic elixir.

Unfortunately, while I have a lot of experience in software development in general and python in particular, I don't have the pytest / flask-dance / flask-security background needed to solve this.

in settings.py

class Testing():
    # default database
    SQLALCHEMY_DATABASE_URI = 'sqlite:///:memory:'

    TESTING = True
    WTF_CSRF_ENABLED = False

    # need to set SERVER_NAME to something, else get a RuntimeError about not able to create URL adapter
    SERVER_NAME = 'dev.localhost'

    # need a default secret key - in production replace by config file
    SECRET_KEY = "<test secret key>"

    # fake  credentials
    GOOGLE_OAUTH_CLIENT_ID = 'fake-client-id'
    GOOGLE_OAUTH_CLIENT_SECRET = 'fake-client-secret'

    # need to allow logins in flask-security. see https://github.com/mattupstate/flask-security/issues/259
    LOGIN_DISABLED = False

in conftest.py

import pytest

from racesupportcontracts import create_app
from racesupportcontracts.dbmodel import db
from racesupportcontracts.settings import Testing

@pytest.fixture
def app():
    app = create_app(Testing)
    yield app

@pytest.fixture
def dbapp(app):
    db.drop_all()
    db.create_all()
    yield app

in test_basic.py

def login_test_user(email):
    from racesupportcontracts.dbmodel import db, User
    from flask_security import login_user
    user = User.query.filter_by(email=email).one()
    login_user(user)
    db.session.commit()

def test_login(dbapp):
    app = dbapp
    from racesupportcontracts.dbmodel import db, init_db
    from racesupportcontracts import user_datastore
    from flask import url_for
    # init_db should create at least superadmin, admin roles
    init_db(defineowner=False)
    useremail = 'testuser@example.com'
    with app.test_client() as client:
        create_user(useremail, 'superadmin')
        login_test_user(useremail)
        resp = client.get('/', follow_redirects=True)
        assert resp.status_code == 200
        assert url_for('admin.logout') in resp.data

singingwolfboy · Accepted Answer · 2019-07-25T07:41:13.563

When you call login_user(), that modifies the flask.session object. However, when using the test client, you can only modify flask.session inside of a session transaction. It should work if you do this:

with app.test_client() as client:
    with client.session_transaction() as sess:
        sess["user_id"] = 1  # if you want user 1 to be logged in for this test

    resp = client.get('/', follow_redirects=True)
    # make whatever assertions you want

If you install the latest version of Flask-Login from GitHub, you can also use the FlaskLoginClient class to make this more readable:

# in conftest.py
from flask_login import FlaskLoginClient

@pytest.fixture
def app():
    app = create_app(Testing)
    app.test_client_class = FlaskLoginClient
    yield app


# in test_basic.py
def test_login(app):
    user = User.query.filter_by(email='testuser@example.com').one()
    with app.test_client(user=user) as client:
        resp = client.get('/', follow_redirects=True)
        # make whatever assertions you want

Unfortunately, the author of Flask-Login refuses to publish an update of the package to PyPI, so you can't use the version of Flask-Login that is on PyPI, you have to install from GitHub. (I have no idea why he refuses to publish an update.)

Will assume this answer is correct and mark it so. But I have abandoned use of flask-dance due to https://github.com/singingwolfboy/flask-dance/issues/182. BTW, do you mean the author of flask-login refuses to publish an update? — Lou K, Jul 16 '19 at 15:25
Ah but I see that this answer doesn't really depend on flask-dance, does it? Unfortunately, I've also abandoned my attempts of unit testing my code. :p — Lou K, Jul 16 '19 at 19:00
@LouK Yes, I meant flask-login! I've edited my answer to be more correct, thank you. — singingwolfboy, Jul 25 '19 at 07:41

struggling to test flask-dance / flask-security / flask-sqlalchemy / pytest

1 Answers1