Add helper class for testing request cancellation (#12630)

Also expose the `SynapseRequest` from `FakeChannel` in tests, so that
we can call `Request.connectionLost` to simulate a client disconnecting.

Signed-off-by: Sean Quah <seanq@element.io>
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Sean Quah 2022-05-10 14:06:56 +01:00 committed by GitHub
parent 5cfb004595
commit dbb12a0b54
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4 changed files with 127 additions and 0 deletions

1
changelog.d/12630.misc Normal file
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@ -0,0 +1 @@
Add a helper class for testing request cancellation.

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@ -0,0 +1,13 @@
# Copyright 2022 The Matrix.org Foundation C.I.C.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

100
tests/http/server/_base.py Normal file
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@ -0,0 +1,100 @@
# Copyright 2022 The Matrix.org Foundation C.I.C.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unles4s required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
from http import HTTPStatus
from typing import Any, Callable, Optional, Union
from unittest import mock
from twisted.internet.error import ConnectionDone
from synapse.http.server import (
HTTP_STATUS_REQUEST_CANCELLED,
respond_with_html_bytes,
respond_with_json,
)
from synapse.types import JsonDict
from tests import unittest
from tests.server import FakeChannel, ThreadedMemoryReactorClock
class EndpointCancellationTestHelperMixin(unittest.TestCase):
"""Provides helper methods for testing cancellation of endpoints."""
def _test_disconnect(
self,
reactor: ThreadedMemoryReactorClock,
channel: FakeChannel,
expect_cancellation: bool,
expected_body: Union[bytes, JsonDict],
expected_code: Optional[int] = None,
) -> None:
"""Disconnects an in-flight request and checks the response.
Args:
reactor: The twisted reactor running the request handler.
channel: The `FakeChannel` for the request.
expect_cancellation: `True` if request processing is expected to be
cancelled, `False` if the request should run to completion.
expected_body: The expected response for the request.
expected_code: The expected status code for the request. Defaults to `200`
or `499` depending on `expect_cancellation`.
"""
# Determine the expected status code.
if expected_code is None:
if expect_cancellation:
expected_code = HTTP_STATUS_REQUEST_CANCELLED
else:
expected_code = HTTPStatus.OK
request = channel.request
self.assertFalse(
channel.is_finished(),
"Request finished before we could disconnect - "
"was `await_result=False` passed to `make_request`?",
)
# We're about to disconnect the request. This also disconnects the channel, so
# we have to rely on mocks to extract the response.
respond_method: Callable[..., Any]
if isinstance(expected_body, bytes):
respond_method = respond_with_html_bytes
else:
respond_method = respond_with_json
with mock.patch(
f"synapse.http.server.{respond_method.__name__}", wraps=respond_method
) as respond_mock:
# Disconnect the request.
request.connectionLost(reason=ConnectionDone())
if expect_cancellation:
# An immediate cancellation is expected.
respond_mock.assert_called_once()
args, _kwargs = respond_mock.call_args
code, body = args[1], args[2]
self.assertEqual(code, expected_code)
self.assertEqual(request.code, expected_code)
self.assertEqual(body, expected_body)
else:
respond_mock.assert_not_called()
# The handler is expected to run to completion.
reactor.pump([1.0])
respond_mock.assert_called_once()
args, _kwargs = respond_mock.call_args
code, body = args[1], args[2]
self.assertEqual(code, expected_code)
self.assertEqual(request.code, expected_code)
self.assertEqual(body, expected_body)

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@ -109,6 +109,17 @@ class FakeChannel:
_ip: str = "127.0.0.1"
_producer: Optional[Union[IPullProducer, IPushProducer]] = None
resource_usage: Optional[ContextResourceUsage] = None
_request: Optional[Request] = None
@property
def request(self) -> Request:
assert self._request is not None
return self._request
@request.setter
def request(self, request: Request) -> None:
assert self._request is None
self._request = request
@property
def json_body(self):
@ -322,6 +333,8 @@ def make_request(
channel = FakeChannel(site, reactor, ip=client_ip)
req = request(channel, site)
channel.request = req
req.content = BytesIO(content)
# Twisted expects to be at the end of the content when parsing the request.
req.content.seek(0, SEEK_END)