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"""Auxiliary fixtures to simplify testing."""
import asyncio
import inspect
import sys
import threading
import channels
import django
import graphene
import pytest
import channels_graphql_ws
import channels_graphql_ws.testing
@pytest.fixture
def event_loop(request):
"""Overwrite `pytest_asyncio` eventloop to fix Windows issue.
Default implementation causes `NotImplementedError` on Windows with
Python 3.8, because they changed default eventloop in 3.8.
NOTE: We do the same thing in the `example/settings.py` because it
imports (and fails) before we have a chance to invoke this fixture.
So, we could avoid adding this fixture, but I feel it is better to
keep the proper solution here as well.
"""
if sys.platform == "win32" and sys.version_info.minor >= 8:
asyncio.set_event_loop_policy(
asyncio.WindowsSelectorEventLoopPolicy() # pylint: disable=no-member
)
loop = asyncio.get_event_loop_policy().new_event_loop()
yield loop
loop.close()
@pytest.fixture
def gql(db, request):
"""PyTest fixture for testing GraphQL WebSocket backends.
The fixture provides a method to setup GraphQL testing backend for
the given GraphQL schema (query, mutation, and subscription). In
particular: it sets up an instance of `GraphqlWsConsumer` and an
instance of `GraphqlWsClient`. The former one is returned
from the function.
Syntax:
gql(
*,
query=None,
mutation=None,
subscription=None,
consumer_attrs=None,
communicator_kwds=None
):
Args:
query: Root GraphQL query. Optional.
mutation: Root GraphQL subscription. Optional.
subscription: Root GraphQL mutation. Optional.
consumer_attrs: `GraphqlWsConsumer` attributes dict. Optional.
communicator_kwds: Extra keyword arguments for the Channels
`channels.testing.WebsocketCommunicator`. Optional.
Returns:
An instance of the `GraphqlWsClient` class which has many
useful GraphQL-related methods, see the `GraphqlWsClient`
class docstrings for details.
Use like this:
```
def test_something(gql):
client = gql(
# GraphQl schema.
query=MyQuery,
mutation=MyMutation,
subscription=MySubscription,
# `GraphqlWsConsumer` settings.
consumer_attrs={"strict_ordering": True},
# `channels.testing.WebsocketCommunicator` settings.
communicator_kwds={"headers": [...]}
)
...
```
"""
# NOTE: We need Django DB to be initialized each time we work with
# `GraphqlWsConsumer`, because it uses threads and sometimes calls
# `django.db.close_old_connections()`.
del db
issued_clients = []
def client_constructor(
*,
query=None,
mutation=None,
subscription=None,
consumer_attrs=None,
communicator_kwds=None,
):
"""Setup GraphQL consumer and the communicator for tests."""
class ChannelsConsumer(channels_graphql_ws.GraphqlWsConsumer):
"""Channels WebSocket consumer for GraphQL API."""
schema = graphene.Schema(
query=query,
mutation=mutation,
subscription=subscription,
auto_camelcase=False,
)
# Set additional attributes to the `ChannelsConsumer`.
if consumer_attrs is not None:
for attr, val in consumer_attrs.items():
setattr(ChannelsConsumer, attr, val)
application = channels.routing.ProtocolTypeRouter(
{
"websocket": channels.routing.URLRouter(
[django.urls.path("graphql/", ChannelsConsumer)]
)
}
)
transport = channels_graphql_ws.testing.GraphqlWsTransport(
application=application,
path="graphql/",
communicator_kwds=communicator_kwds,
)
client = channels_graphql_ws.testing.GraphqlWsClient(transport)
issued_clients.append(client)
return client
yield client_constructor
# Assert all issued client are properly finalized.
for client in reversed(issued_clients):
assert (
not client.connected
), f"Test has left connected client: {request.node.nodeid}!"
@pytest.fixture(scope="session", autouse=True)
def synchronize_inmemory_channel_layer():
"""Monkeypatch `InMemoryChannelLayer` to make it thread safe.
Without this we have a blinking fails in the unit tests run:
Traceback (most recent call last):
File ".../site-packages/promise/promise.py", line 842, in handle_future_result
resolve(future.result())
File ".../tests/test_concurrent.py", line 994, in mutate
await OnChatMessageSentAsync.notify(message=message, user_id=user_id)
File ".../tests/test_concurrent.py", line 940, in notify
await super().broadcast(group=group, payload=message)
File ".../channels_graphql_ws/graphql_ws.py", line 248, in broadcast_async
"payload": serialized_payload,
File ".../site-packages/channels/layers.py", line 351, in group_send
for channel in self.groups.get(group, set()):
graphql.error.located_error.GraphQLLocatedError:
dictionary changed size during iteration
"""
guard = threading.RLock()
def wrap(func):
if inspect.iscoroutinefunction(func):
async def wrapper(*args, **kwds):
with guard:
return await func(*args, **kwds)
else:
def wrapper(*args, **kwds):
with guard:
return func(*args, **kwds)
return wrapper
# Carefully selected methods to protect. We cannot simply wrap all
# the callables, cause this will lead to deadlocks, e.g. when we
# locked the mutex in `await receive` and then another coroutine
# calls `await send`.
callables_to_protect = [
"_clean_expired",
"_remove_from_groups",
"close",
"flush",
"group_add",
"group_discard",
"group_send",
"new_channel",
"send",
]
for attr_name in callables_to_protect:
setattr(
channels.layers.InMemoryChannelLayer,
attr_name,
wrap(getattr(channels.layers.InMemoryChannelLayer, attr_name)),
)
@pytest.fixture(scope="function", autouse=True)
def extra_print_in_the_beginning():
"""Improve output of `pytest -s` by adding EOL in the beginning."""
print()
