WebSocket Unit Test Not Working in Django with TransactionTestCase

Question

I'm building a simple app where users can join tables to play chess, connecting via WebSocket. Everything works as intended in the development environment: users can log in, join rooms, sit at tables, and move pieces without any WebSocket connection issues.

However, when I try to write a unit test using TransactionTestCase, the connection attempt fails. Specifically, the connected value in connected, subprotocol = await communicator.connect() returns False, even though there are no problems in the development environment.

Here's a simplified version of my setup:

WebSocket Consumer (consumers.py):

class TableConsumer(AsyncWebsocketConsumer):
    async def connect(self):
        self.table_id = self.scope["url_route"]["kwargs"]["table_id"]
        self.table_group_id = f"table_{self.table_id}"

        # Join the room group
        await self.channel_layer.group_add(self.table_group_id, self.channel_name)
        await self.accept()

        # Send the current game state to the new connection
        await self.send_current_state()

Unit Test (tests.py):

from channels.testing import WebsocketCommunicator
from django.test import TransactionTestCase, SimpleTestCase, TestCase
from django.conf import settings
from chess_django.asgi import application

from .models import Game, Board
from asgiref.sync import sync_to_async

class ChannelLayerSettingsTest(TestCase):
    def test_channel_layers_for_testing(self):
        self.assertEqual(
            settings.CHANNEL_LAYERS['default']['BACKEND'],
            "channels.layers.InMemoryChannelLayer"
        )

class WebSocketTests(TransactionTestCase):
    async def test_websocket_connect(self):
        new_game = await sync_to_async(Game.objects.create)()

        communicator = WebsocketCommunicator(application, f"/ws/table/{new_game.id}/")
        connected, subprotocol = await communicator.connect()
        self.assertTrue(connected)

        await communicator.disconnect()

ASGI Configuration (asgi.py):

import os
from channels.auth import AuthMiddlewareStack
from channels.routing import ProtocolTypeRouter, URLRouter
from channels.security.websocket import AllowedHostsOriginValidator
from django.core.asgi import get_asgi_application

os.environ.setdefault('DJANGO_SETTINGS_MODULE', 'chess_django.settings')
django_asgi_app = get_asgi_application()

import table.routing

application = ProtocolTypeRouter(
    {
        "http": get_asgi_application(),
        "websocket": AllowedHostsOriginValidator(
            AuthMiddlewareStack(URLRouter(table.routing.websocket_urlpatterns))
        ),
    }
)

Routing (routing.py):

from django.urls import re_path

from . import consumers

websocket_urlpatterns = [
    re_path(r"ws/table/(?P<table_id>\w+)/$", consumers.TableConsumer.as_asgi()),
]

Settings (settings.py):

INSTALLED_APPS = [
    'daphne',
    'channels',
    'table',
    'menu',
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
]

#...

ASGI_APPLICATION = "chess_django.asgi.application"
if "test" in sys.argv:
    CHANNEL_LAYERS = {
    "default": {
        "BACKEND": "channels.layers.InMemoryChannelLayer",
        },
    }
else:
    CHANNEL_LAYERS = {
        "default": {
            "BACKEND": "channels_redis.core.RedisChannelLayer",
            "CONFIG": {
                "hosts": [("127.0.0.1", 6379)],
            },
        },
    }

Issue: When running the test, the connection fails, with connected being False. This issue does not occur in the development environment where everything functions correctly. I tried without mocking CHANNEL_LAYERS (using default channels_redis), and the test still failed.

Here is a link https://github.com/Przekazmierczak/chess_not_finished to my GitHub repository with the full project setup.

What could be causing this issue in the test environment, and how can I fix it?

Any help would be greatly appreciated!