Re: [django-channels] Testing events from post_save signal

-----BEGIN PGP SIGNATURE-----
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=KKZT
-----END PGP SIGNATURE-----
Kudos for you and all contributors! It's really amazing.

I'm going to send few PRs to django-channels as a payback :)

Cheers,

   Tom

25. 2. 2018 v 19:46, Andrew Godwin <andrew@aeracode.org>:

No problem - glad everything else seems to work alright! Getting async testing working well has been a long, hard road :)

Andrew

On Sun, Feb 25, 2018 at 10:37 AM, Tomáš Ehrlich <tomas.ehrlich@gmail.com> wrote:

Of course!

It works now perfectly, thank you. Sorry I missed that in docs.

Cheers,

   Tom

25. 2. 2018 v 19:12, Andrew Godwin <andrew@aeracode.org>:

I think the change you need to make is swapping in database_sync_to_async rather than sync_to_async - see here: http://channels.readthedocs.io/en/latest/topics/databases.html

Andrew

On Sun, Feb 25, 2018 at 7:14 AM, Tomáš Ehrlich <tomas.ehrlich@gmail.com> wrote:

Here's the gist (https://gist.github.com/tricoder42/af3d0337c1b33d82c1b32d12bd0265ec) with consumer.

Dne neděle 25. února 2018 15:37:19 UTC+1 Tomáš Ehrlich napsal(a):

Hello,

I've just migrated my project to django-channels 2.x. Thanks to everyone involved!

I'm trying to write a test for a consumer.

I have a post_save signal receiver, which sends a message to a group. As I understand,

I need to wrap `group_send` with `async_to_sync` because django signals can't be

async functions:

def notify_on_model_changes(model):
    from django.contrib.contenttypes.models import ContentType
    ct = ContentType.objects.get_for_model(model)
    model_label = '.'.join([ct.app_label, ct.model])

    channel_layer = get_channel_layer()

    group_send = async_to_sync(channel_layer.group_send)

    def receiver(sender, instance, **kwargs):
        payload = {
            'type': 'model.changed',
            'pk': instance.pk,
            'model': model_label
        }     
        group_send(f'django.{model_label}', payload)

    post_save.connect(receiver, sender=model, weak=False,
                      dispatch_uid=f'django.{model_label}')

# in AppConfig.ready:

# notify_on_model_changes(Conversation)

My test suite, however, is async function:

@pytest.fixture
async def communicator():
    communicator = WebsocketCommunicator(GraphqlSubcriptionConsumer, "/")
    await communicator.connect()
    yield communicator
    await communicator.disconnect()
    
async def test_subscription_start(communicator):
    def make_conversation():
        return Conversation.objects.create()

    # function body truncated

    # subscribe for changes in Conversation model
    await communicator.send_json_to(data)

    conversation = await sync_to_async(make_conversation)()
    response = await communicator.receive_json_from()
    assert response['type'] == 'data'

I can't use `Conversation.objects.create()` directly, because it uses `async_to_sync`.

First, I need to convert it to async and await the result. I kinda feel this is hackish

jumping from async to sync and back to async, but so far everything works as expected

and test works.

Here comes the punchline:

The tests fail to teardown cleanly, because apparently there's hanging DB connection

and after a while pytest just fails with `There is 1 other session using the database.`.

Breadcrumbs:

1. If I comment out last three lines of test (make_conversations and waiting for result),

the test exits cleanly - seems like there's no problem with passing `sync_to_async` function

to `post_save.connect`.

2. If I create `async_make = sync_to_async(make_conversation)`, but don't call it at all,

the test exists cleanly - I thought that there might be problem with calling `async_to_sync`

inside code wrapped with `sync_to_async`.

I suspect there's a hanging db connection which isn't cleaned and/or garbage collected.

I would also appreciate any comments about structure of such tests - is there cleaner way

test django signals inside async test cases?

Cheers,

   Tom

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscribe@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.

To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/af745c4f-7571-40d3-b738-1593d4d75bbb%40googlegroups.com.

For more options, visit https://groups.google.com/d/optout.

--

You received this message because you are subscribed to a topic in the Google Groups "Django users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/django-users/HD-gijCEgqM/unsubscribe.
To unsubscribe from this group and all its topics, send an email to django-users+unsubscribe@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAFwN1upHZSCzicBndZsqbSVZyA-erHmkfNnqUr-nNFAXBs9DjQ%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to the Google Groups "Django users" group.
To unsubscribe from this group and stop receiving emails from it, send an email to django-users+unsubscribe@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/569A1F66-337C-4304-A686-0ACEA8F142A8%40gmail.com.

For more options, visit https://groups.google.com/d/optout.

--
You received this message because you are subscribed to a topic in the Google Groups "Django users" group.
To unsubscribe from this topic, visit https://groups.google.com/d/topic/django-users/HD-gijCEgqM/unsubscribe.
To unsubscribe from this group and all its topics, send an email to django-users+unsubscribe@googlegroups.com.
To post to this group, send email to django-users@googlegroups.com.
Visit this group at https://groups.google.com/group/django-users.
To view this discussion on the web visit https://groups.google.com/d/msgid/django-users/CAFwN1up%2B7mD-pUuR4GeChKutMh9nE5257AOAKH9DvxKoiJ%2BZdw%40mail.gmail.com.
For more options, visit https://groups.google.com/d/optout.