Additional test for `cachedList` (#11246)

I was trying to understand how `cachedList` works, and ended up writing this
extra test. I figure we may as well keep it.
pull/11253/head
Richard van der Hoff 2021-11-04 14:45:34 +00:00 committed by GitHub
parent 8eec25a1d9
commit f36434590c
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changelog.d/11246.misc Normal file
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@ -0,0 +1 @@
Add an additional test for the `cachedList` method decorator.

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@ -17,6 +17,7 @@ from typing import Set
from unittest import mock
from twisted.internet import defer, reactor
from twisted.internet.defer import Deferred
from synapse.api.errors import SynapseError
from synapse.logging.context import (
@ -703,6 +704,48 @@ class CachedListDescriptorTestCase(unittest.TestCase):
obj.mock.assert_called_once_with((40,), 2)
self.assertEqual(r, {10: "fish", 40: "gravy"})
def test_concurrent_lookups(self):
"""All concurrent lookups should get the same result"""
class Cls:
def __init__(self):
self.mock = mock.Mock()
@descriptors.cached()
def fn(self, arg1):
pass
@descriptors.cachedList("fn", "args1")
def list_fn(self, args1) -> "Deferred[dict]":
return self.mock(args1)
obj = Cls()
deferred_result = Deferred()
obj.mock.return_value = deferred_result
# start off several concurrent lookups of the same key
d1 = obj.list_fn([10])
d2 = obj.list_fn([10])
d3 = obj.list_fn([10])
# the mock should have been called exactly once
obj.mock.assert_called_once_with((10,))
obj.mock.reset_mock()
# ... and none of the calls should yet be complete
self.assertFalse(d1.called)
self.assertFalse(d2.called)
self.assertFalse(d3.called)
# complete the lookup. @cachedList functions need to complete with a map
# of input->result
deferred_result.callback({10: "peas"})
# ... which should give the right result to all the callers
self.assertEqual(self.successResultOf(d1), {10: "peas"})
self.assertEqual(self.successResultOf(d2), {10: "peas"})
self.assertEqual(self.successResultOf(d3), {10: "peas"})
@defer.inlineCallbacks
def test_invalidate(self):
"""Make sure that invalidation callbacks are called."""