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# Copyright 2021 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.
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):
"""
Happy-path test case: makes a couple of calls and makes sure they behave
correctly
"""
d = Deferred()
async def f():
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():
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):
"""
Test the behaviour when the underlying function completes immediately
"""
async def f():
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):
# set up the RetryOnExceptionCachedCall around a function which will fail
# (after a while)
d = Deferred()
async def f1():
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():
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():
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()
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