Django channels 2, accessing db in tests - django

Question

I recently updated my project to Django 2 and channels 2. Right now I am trying to rewrite my tests for chat app.
I am facing a problem with tests that depend on django db mark from pytest-django. I tried to create objects in fixtures, setup methods, in test function itself, using async_to_sync on WebsocketCommunicator. However, none of those worked.
If I create a user in a fixture and save it correctly gets an id. However, in my consumer Django does not see that User in the database. And treat it like an anonymous user.
I have a temporary token which I use to authenticate a user on websocket.connect.
#pytest.fixture
def room():
room = generate_room()
room.save()
return room
#pytest.fixture
def room_with_user(room, normal_user):
room.users.add(normal_user)
yield room
room.users.remove(normal_user)
#pytest.fixture
def normal_user():
user = generate_user()
user.save()
return user
#pytest.mark.django_db
class TestConnect:
#pytest.mark.asyncio
async def test_get_connected_client(self, path, room_with_user, temp_token):
assert get_path(room_with_user.id) == path
communicator = QSWebsocketCommunicator(application, path, query_string=get_query_string(temp_token))
connected, subprotocol = await communicator.connect()
assert connected
await communicator.disconnect()
Consumer:
class ChatConsumer(JsonWebsocketConsumer):
def connect(self):
# Called on connection. Either call
self.user = self.scope['user']
self.room_id = self.scope['url_route']['kwargs']['room_id']
group = f'room_{self.room_id}'
users = list(User.objects.all()) # no users here
self.group_name = group
if not (self.user is not None and self.user.is_authenticated):
return self.close({'Error': 'Not authenticated user'})
try:
self.room = Room.objects.get(id=self.room_id, users__id=self.user.id)
except ObjectDoesNotExist:
return self.close({'Error': 'Room does not exists'})
# Send success response
self.accept()
# Save user as active
self.room.active_users.add(self.user)
My authentication Middleware
class OAuthTokenAuthMiddleware:
"""
Custom middleware that takes Authorization header and read OAuth token from it.
"""
def __init__(self, inner):
# Store the ASGI application we were passed
self.inner = inner
def __call__(self, scope):
temp_token = self.get_token(scope)
scope['user'] = self.validate_token(temp_token)
return self.inner(scope)
#staticmethod
def get_token(scope) -> str:
return url_parse.parse_qs(scope['query_string'])[b'token'][0].decode("utf-8")
#staticmethod
def validate_token(token):
try:
token = TemporaryToken.objects.select_related('user').get(token=token)
if token.is_active():
token.delete()
return token.user
else:
return AnonymousUser()
except ObjectDoesNotExist:
return AnonymousUser()
And custom WebsocketCommunicator which accepts query_string in order to include my one time token
class QSWebsocketCommunicator(WebsocketCommunicator):
def __init__(self, application, path, headers=None, subprotocols=None,
query_string: Optional[Union[str, bytes]]=None):
if isinstance(query_string, str):
query_string = str.encode(query_string)
self.scope = {
"type": "websocket",
"path": path,
"headers": headers or [],
"subprotocols": subprotocols or [],
"query_string": query_string or ''
}
ApplicationCommunicator.__init__(self, application, self.scope)
My question is how can I create User, Room, etc. objects in tests/fixtures so that I can access them in Django consumer.
Or do you have another idea how can I overcome this?

Answer 1

It's pretty much impossible to reproduce your issue using the code you've provided. Read about How to create a Minimal, Complete, and Verifiable example. However, I suppose that you should use real transactions in your test as the plain pytest.mark.django_db will skip the transactions and not store any data in the database per se. A working example:
# routing.py
from django import http
from django.conf.urls import url
from django.contrib.auth.models import User
from channels.routing import ProtocolTypeRouter, URLRouter
from channels.generic.websocket import JsonWebsocketConsumer
class ChatConsumer(JsonWebsocketConsumer):
def connect(self):
self.user = self.scope['user']
print('user in scope, set by middleware:', self.user)
users = list(User.objects.all()) # no users here
print('all users in chat consumer:', users)
if not (self.user is not None and self.user.is_authenticated):
return self.close({'Error': 'Not authenticated user'})
# Send success response
self.accept()
class OAuthTokenAuthMiddleware:
def __init__(self, inner):
# Store the ASGI application we were passed
self.inner = inner
def __call__(self, scope):
token = self.get_token(scope)
print('token in middleware:', token)
scope['user'] = User.objects.get(username=token)
return self.inner(scope)
#staticmethod
def get_token(scope) -> str:
d = http.QueryDict(scope['query_string'])
return d['token']
APP = ProtocolTypeRouter({
'websocket': OAuthTokenAuthMiddleware(URLRouter([url(r'^websocket/$', ChatConsumer)])),
})
Sample fixture that creates a user with username spam:
#pytest.fixture(scope='function', autouse=True)
def create_user():
with transaction.atomic():
User.objects.all().delete()
user = User.objects.create_user(
'spam', 'spam#example.com', password='eggs',
first_name='foo', last_name='bar'
)
return user
Now, I mark the test as transactional one, meaning that each query is actually committed. Now the test user is stored into database and the queries made in middleware/consumer can actually return something meaningful:
#pytest.mark.django_db(transaction=True)
#pytest.mark.asyncio
async def test_get_connected_client():
app = OAuthTokenAuthMiddleware(URLRouter([url(r'^websocket/$', ChatConsumer)]))
communicator = QSWebsocketCommunicator(app, '/websocket/', query_string='token=spam')
connected, subprotocol = await communicator.connect()
assert connected
await communicator.disconnect()
Running test test yields the desired result:
$ pytest -vs
================================== test session starts =================================
platform darwin -- Python 3.6.3, pytest-3.4.0, py-1.5.2, pluggy-0.6.0 -- /Users/hoefling/.virtualenvs/stackoverflow/bin/python
cachedir: .pytest_cache
Django settings: spam.settings (from environment variable)
rootdir: /Users/hoefling/projects/private/stackoverflow/so-49136564/spam, inifile: pytest.ini
plugins: celery-4.1.0, forked-0.2, django-3.1.2, cov-2.5.1, asyncio-0.8.0, xdist-1.22.0, mock-1.6.3, hypothesis-3.44.4
collected 1 item
tests/test_middleware.py::test_get_connected_client Creating test database for alias 'default'...
token in middleware: spam
user in scope: spam
all users in chat consumer: [<User: spam>]
PASSEDDestroying test database for alias 'default'...
=============================== 1 passed in 0.38 seconds ================================
Btw you don't need to hack around the WebsocketCommunicator anymore since it is now able to deal with query strings, see this issue closed.