Testing

When building your application you’ll eventually want to test that your sessions are behaving as expected. You can use the InMemorySessionInterface for testing purposes. You’ll want to insert some logic in your application so that in a testing environment, your application uses the InMemorySessionInterface. An example is like follows:

main.py

import asyncio_redis
import os

from sanic import Sanic
from sanic.response import text
from sanic_session import (
    RedisSessionInterface,
    InMemorySessionInterface
)


app = Sanic()


class Redis:
    _pool = None

    async def get_redis_pool(self):
        if not self._pool:
            self._pool = await asyncio_redis.Pool.create(
                host='localhost', port=6379, poolsize=10
            )

        return self._pool


redis = Redis()

# If we are in the testing environment, use the in-memory session interface
if os.environ.get('TESTING'):
    Session(app, interface = InMemorySessionInterface())
else:
    Session(app, interface = RedisSessionInterface(redis.get_redis_pool))


@app.route("/")
async def index(request):
    if not request['session'].get('foo'):
        request['session']['foo'] = 0

    request['session']['foo'] += 1

    response = text(request['session']['foo'])

    return response

if __name__ == "__main__":
    app.run(host="0.0.0.0", port=8000, debug=True)

Let’s say we want to test that the route / does in fact increment a counter on subsequent requests. There’s a few things to remember:

  • When a session is saved, a session parameter is included in the response cookie.

  • Use this session ID to retrieve the server-stored session data from the session_interface.

  • You can also use this session ID on future requests to reuse the same client session.

An example is like follows:

import os
os.environ['TESTING'] = 'True'

from main import app, session_interface

import pytest
import aiohttp
from sanic.utils import sanic_endpoint_test


def test_session_increments_counter():
    request, response = sanic_endpoint_test(app, uri='/')

    # A session ID is passed in the response cookies, save that
    session_id = response.cookies['session'].value

    # retrieve the session data using the session_id
    session = session_interface.get_session(session_id)

    assert session['foo'] == 1, 'foo should initially equal 1'

    # use the session ID to test the endpoint against the same session
    request, response = sanic_endpoint_test(
        app, uri='/', cookies={'session': session_id})

    # again retrieve the session data using the session_id
    session = session_interface.get_session(session_id)

    assert session['foo'] == 2, 'foo should increment on subsequent requests'