216 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Python
		
	
	
			
		
		
	
	
			216 lines
		
	
	
		
			7.2 KiB
		
	
	
	
		
			Python
		
	
	
# Copyright 2021 The Matrix.org Foundation C.I.C.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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#     http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from unittest.mock import Mock
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from parameterized import parameterized
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from twisted.internet import defer
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from synapse.util.caches.response_cache import ResponseCache, ResponseCacheContext
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from tests.server import get_clock
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from tests.unittest import TestCase
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class ResponseCacheTestCase(TestCase):
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    """
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    A TestCase class for ResponseCache.
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    The test-case function naming has some logic to it in it's parts, here's some notes about it:
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        wait: Denotes tests that have an element of "waiting" before its wrapped result becomes available
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              (Generally these just use .delayed_return instead of .instant_return in it's wrapped call.)
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        expire: Denotes tests that test expiry after assured existence.
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                (These have cache with a short timeout_ms=, shorter than will be tested through advancing the clock)
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    """
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    def setUp(self):
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        self.reactor, self.clock = get_clock()
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    def with_cache(self, name: str, ms: int = 0) -> ResponseCache:
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        return ResponseCache(self.clock, name, timeout_ms=ms)
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    @staticmethod
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    async def instant_return(o: str) -> str:
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        return o
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    async def delayed_return(self, o: str) -> str:
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        await self.clock.sleep(1)
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        return o
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    def test_cache_hit(self):
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        cache = self.with_cache("keeping_cache", ms=9001)
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        expected_result = "howdy"
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, self.instant_return, expected_result)
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        )
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        self.assertEqual(
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            expected_result,
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            self.successResultOf(wrap_d),
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            "initial wrap result should be the same",
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        )
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        # a second call should return the result without a call to the wrapped function
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        unexpected = Mock(spec=())
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        wrap2_d = defer.ensureDeferred(cache.wrap(0, unexpected))
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        unexpected.assert_not_called()
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        self.assertEqual(
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            expected_result,
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            self.successResultOf(wrap2_d),
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            "cache should still have the result",
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        )
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    def test_cache_miss(self):
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        cache = self.with_cache("trashing_cache", ms=0)
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        expected_result = "howdy"
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, self.instant_return, expected_result)
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        )
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        self.assertEqual(
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            expected_result,
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            self.successResultOf(wrap_d),
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            "initial wrap result should be the same",
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        )
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        self.assertCountEqual([], cache.keys(), "cache should not have the result now")
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    def test_cache_expire(self):
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        cache = self.with_cache("short_cache", ms=1000)
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        expected_result = "howdy"
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, self.instant_return, expected_result)
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        )
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        self.assertEqual(expected_result, self.successResultOf(wrap_d))
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        # a second call should return the result without a call to the wrapped function
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        unexpected = Mock(spec=())
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        wrap2_d = defer.ensureDeferred(cache.wrap(0, unexpected))
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        unexpected.assert_not_called()
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        self.assertEqual(
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            expected_result,
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            self.successResultOf(wrap2_d),
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            "cache should still have the result",
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        )
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        # cache eviction timer is handled
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        self.reactor.pump((2,))
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        self.assertCountEqual([], cache.keys(), "cache should not have the result now")
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    def test_cache_wait_hit(self):
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        cache = self.with_cache("neutral_cache")
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        expected_result = "howdy"
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, self.delayed_return, expected_result)
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        )
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        self.assertNoResult(wrap_d)
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        # function wakes up, returns result
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        self.reactor.pump((2,))
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        self.assertEqual(expected_result, self.successResultOf(wrap_d))
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    def test_cache_wait_expire(self):
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        cache = self.with_cache("medium_cache", ms=3000)
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        expected_result = "howdy"
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, self.delayed_return, expected_result)
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        )
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        self.assertNoResult(wrap_d)
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        # stop at 1 second to callback cache eviction callLater at that time, then another to set time at 2
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        self.reactor.pump((1, 1))
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        self.assertEqual(expected_result, self.successResultOf(wrap_d))
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        # a second call should immediately return the result without a call to the
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        # wrapped function
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        unexpected = Mock(spec=())
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        wrap2_d = defer.ensureDeferred(cache.wrap(0, unexpected))
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        unexpected.assert_not_called()
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        self.assertEqual(
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            expected_result,
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            self.successResultOf(wrap2_d),
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            "cache should still have the result",
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        )
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        # (1 + 1 + 2) > 3.0, cache eviction timer is handled
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        self.reactor.pump((2,))
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        self.assertCountEqual([], cache.keys(), "cache should not have the result now")
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    @parameterized.expand([(True,), (False,)])
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    def test_cache_context_nocache(self, should_cache: bool):
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        """If the callback clears the should_cache bit, the result should not be cached"""
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        cache = self.with_cache("medium_cache", ms=3000)
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        expected_result = "howdy"
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        call_count = 0
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        async def non_caching(o: str, cache_context: ResponseCacheContext[int]):
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            nonlocal call_count
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            call_count += 1
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            await self.clock.sleep(1)
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            cache_context.should_cache = should_cache
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            return o
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        wrap_d = defer.ensureDeferred(
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            cache.wrap(0, non_caching, expected_result, cache_context=True)
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        )
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        # there should be no result to start with
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        self.assertNoResult(wrap_d)
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        # a second call should also return a pending deferred
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        wrap2_d = defer.ensureDeferred(
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            cache.wrap(0, non_caching, expected_result, cache_context=True)
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        )
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        self.assertNoResult(wrap2_d)
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        # and there should have been exactly one call
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        self.assertEqual(call_count, 1)
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        # let the call complete
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        self.reactor.advance(1)
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        # both results should have completed
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        self.assertEqual(expected_result, self.successResultOf(wrap_d))
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        self.assertEqual(expected_result, self.successResultOf(wrap2_d))
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        if should_cache:
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            unexpected = Mock(spec=())
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            wrap3_d = defer.ensureDeferred(cache.wrap(0, unexpected))
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            unexpected.assert_not_called()
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            self.assertEqual(
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                expected_result,
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                self.successResultOf(wrap3_d),
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                "cache should still have the result",
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            )
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        else:
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            self.assertCountEqual(
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                [], cache.keys(), "cache should not have the result now"
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            )
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