Creating a live_server pytest fixture arround Daphne

[medihack]

Similar to the pytest-django live_server I would like to create a fixture for Django Channels with Daphne.

There are some code resources I looked at: live_server, LiveServer, ChannelsLiveServerTestCase and DaphneProcess

Here is what I have so far:

from functools import partial
import pytest
from channels.routing import get_default_application
from daphne.testing import DaphneProcess
from django.contrib.staticfiles.handlers import ASGIStaticFilesHandler
from django.core.exceptions import ImproperlyConfigured
from django.test.utils import modify_settings
from playwright.sync_api import Page


def make_application(*, static_wrapper):
    # Module-level function for pickle-ability
    application = get_default_application()
    if static_wrapper is not None:
        application = static_wrapper(application)
    return application


class ChannelsLiveServer:
    host = "localhost"
    ProtocolServerProcess = DaphneProcess
    static_wrapper = ASGIStaticFilesHandler
    serve_static = True

    def __init__(self) -> None:
        from django.db import connections

        for connection in connections.all():
            if connection.vendor == "sqlite" and connection.is_in_memory_db():
                raise ImproperlyConfigured(
                    "ChannelsLiveServer can not be used with in memory databases"
                )

        self._live_server_modified_settings = modify_settings(ALLOWED_HOSTS={"append": self.host})
        self._live_server_modified_settings.enable()

        get_application = partial(
            make_application,
            static_wrapper=self.static_wrapper if self.serve_static else None,
        )

        self._server_process = self.ProtocolServerProcess(self.host, get_application)
        self._server_process.start()
        self._server_process.ready.wait()
        self._port = self._server_process.port.value

    def stop(self) -> None:
        self._server_process.terminate()
        self._server_process.join()
        self._live_server_modified_settings.disable()

    @property
    def url(self) -> str:
        return f"http://{self.host}:{self._port}"


@pytest.fixture(scope="session")
def channels_liver_server(request):
    server = ChannelsLiveServer()
    request.addfinalizer(server.stop)
    return server


@pytest.mark.integration
def test_something(page: Page, channels_liver_server):
    print(channels_liver_server.url)
    page.goto(channels_liver_server.url)

Unfortunately, when running the test test_something (using Playwright) I get the following error:

adit/selective_transfer/tests/integration/test_selective_transfer.py [2022-11-09 08:31:08 UTC] daphne.server INFO HTTP/2 support enabled
[2022-11-09 08:31:08 UTC] daphne.server INFO Configuring endpoint tcp:port=0:interface=localhost
[2022-11-09 08:31:08 UTC] daphne.server INFO Listening on TCP address 127.0.0.1:43775
http://localhost:43775
[2022-11-09 08:31:09 UTC] daphne.http_protocol ERROR Traceback (most recent call last):
  File "/opt/pysetup/.venv/lib/python3.10/site-packages/daphne/http_protocol.py", line 163, in process
    self.application_queue = yield maybeDeferred(
TypeError: get_default_application() got an unexpected keyword argument 'scope'

I have no problem when just using live_server or using the ChannelsLiveServerTestCase class. But I need that fixture, because there are several other fixtures I need to use as well that can't be used with a test class. It would also be a nice addition to pytest-django (see pytest-dev/pytest-django#1027).

Has someone a clue what causes the error?

[medihack]

It seems it's just a version problem. I used Channels / Daphne 3.0.5, but the above is for Channels / Daphne 4.0.0. In version 3 the DaphneProcess server expects the application itself and not a getter function.