synapse/tests/util/caches/test_cached_call.py
Erik Johnston 23740eaa3d
Correctly mention previous copyright (#16820)
During the migration the automated script to update the copyright
headers accidentally got rid of some of the existing copyright lines.
Reinstate them.
2024-01-23 11:26:48 +00:00

168 lines
5.2 KiB
Python

#
# This file is licensed under the Affero General Public License (AGPL) version 3.
#
# Copyright 2021 The Matrix.org Foundation C.I.C.
# Copyright (C) 2023 New Vector, Ltd
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 of the
# License, or (at your option) any later version.
#
# See the GNU Affero General Public License for more details:
# <https://www.gnu.org/licenses/agpl-3.0.html>.
#
# Originally licensed under the Apache License, Version 2.0:
# <http://www.apache.org/licenses/LICENSE-2.0>.
#
# [This file includes modifications made by New Vector Limited]
#
#
from typing import NoReturn
from unittest.mock import Mock
from twisted.internet import defer
from twisted.internet.defer import Deferred
from synapse.util.caches.cached_call import CachedCall, RetryOnExceptionCachedCall
from tests.test_utils import get_awaitable_result
from tests.unittest import TestCase
class CachedCallTestCase(TestCase):
def test_get(self) -> None:
"""
Happy-path test case: makes a couple of calls and makes sure they behave
correctly
"""
d: "Deferred[int]" = Deferred()
async def f() -> int:
return await d
slow_call = Mock(side_effect=f)
cached_call = CachedCall(slow_call)
# the mock should not yet have been called
slow_call.assert_not_called()
# now fire off a couple of calls
completed_results = []
async def r() -> None:
res = await cached_call.get()
completed_results.append(res)
r1 = defer.ensureDeferred(r())
r2 = defer.ensureDeferred(r())
# neither result should be complete yet
self.assertNoResult(r1)
self.assertNoResult(r2)
# and the mock should have been called *once*, with no params
slow_call.assert_called_once_with()
# allow the deferred to complete, which should complete both the pending results
d.callback(123)
self.assertEqual(completed_results, [123, 123])
self.successResultOf(r1)
self.successResultOf(r2)
# another call to the getter should complete immediately
slow_call.reset_mock()
r3 = get_awaitable_result(cached_call.get())
self.assertEqual(r3, 123)
slow_call.assert_not_called()
def test_fast_call(self) -> None:
"""
Test the behaviour when the underlying function completes immediately
"""
async def f() -> int:
return 12
fast_call = Mock(side_effect=f)
cached_call = CachedCall(fast_call)
# the mock should not yet have been called
fast_call.assert_not_called()
# run the call a couple of times, which should complete immediately
self.assertEqual(get_awaitable_result(cached_call.get()), 12)
self.assertEqual(get_awaitable_result(cached_call.get()), 12)
# the mock should have been called once
fast_call.assert_called_once_with()
class RetryOnExceptionCachedCallTestCase(TestCase):
def test_get(self) -> None:
# set up the RetryOnExceptionCachedCall around a function which will fail
# (after a while)
d: "Deferred[int]" = Deferred()
async def f1() -> NoReturn:
await d
raise ValueError("moo")
slow_call = Mock(side_effect=f1)
cached_call = RetryOnExceptionCachedCall(slow_call)
# the mock should not yet have been called
slow_call.assert_not_called()
# now fire off a couple of calls
completed_results = []
async def r() -> None:
try:
await cached_call.get()
except Exception as e1:
completed_results.append(e1)
r1 = defer.ensureDeferred(r())
r2 = defer.ensureDeferred(r())
# neither result should be complete yet
self.assertNoResult(r1)
self.assertNoResult(r2)
# and the mock should have been called *once*, with no params
slow_call.assert_called_once_with()
# complete the deferred, which should make the pending calls fail
d.callback(0)
self.assertEqual(len(completed_results), 2)
for e in completed_results:
self.assertIsInstance(e, ValueError)
self.assertEqual(e.args, ("moo",))
# reset the mock to return a successful result, and make another pair of calls
# to the getter
d = Deferred()
async def f2() -> int:
return await d
slow_call.reset_mock()
slow_call.side_effect = f2
r3 = defer.ensureDeferred(cached_call.get())
r4 = defer.ensureDeferred(cached_call.get())
self.assertNoResult(r3)
self.assertNoResult(r4)
slow_call.assert_called_once_with()
# let that call complete, and check the results
d.callback(123)
self.assertEqual(self.successResultOf(r3), 123)
self.assertEqual(self.successResultOf(r4), 123)
# and now more calls to the getter should complete immediately
slow_call.reset_mock()
self.assertEqual(get_awaitable_result(cached_call.get()), 123)
slow_call.assert_not_called()