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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 twisted.internet import defer
    
    from synapse.logging.context import make_deferred_yieldable
    from synapse.util.batching_queue import BatchingQueue
    
    from tests.server import get_clock
    from tests.unittest import TestCase
    
    
    class BatchingQueueTestCase(TestCase):
        def setUp(self):
            self.clock, hs_clock = get_clock()
    
            self._pending_calls = []
            self.queue = BatchingQueue("test_queue", hs_clock, self._process_queue)
    
        async def _process_queue(self, values):
            d = defer.Deferred()
            self._pending_calls.append((values, d))
            return await make_deferred_yieldable(d)
    
        def test_simple(self):
            """Tests the basic case of calling `add_to_queue` once and having
            `_process_queue` return.
            """
    
            self.assertFalse(self._pending_calls)
    
            queue_d = defer.ensureDeferred(self.queue.add_to_queue("foo"))
    
            # The queue should wait a reactor tick before calling the processing
            # function.
            self.assertFalse(self._pending_calls)
            self.assertFalse(queue_d.called)
    
            # We should see a call to `_process_queue` after a reactor tick.
            self.clock.pump([0])
    
            self.assertEqual(len(self._pending_calls), 1)
            self.assertEqual(self._pending_calls[0][0], ["foo"])
            self.assertFalse(queue_d.called)
    
            # Return value of the `_process_queue` should be propagated back.
            self._pending_calls.pop()[1].callback("bar")
    
            self.assertEqual(self.successResultOf(queue_d), "bar")
    
        def test_batching(self):
            """Test that multiple calls at the same time get batched up into one
            call to `_process_queue`.
            """
    
            self.assertFalse(self._pending_calls)
    
            queue_d1 = defer.ensureDeferred(self.queue.add_to_queue("foo1"))
            queue_d2 = defer.ensureDeferred(self.queue.add_to_queue("foo2"))
    
            self.clock.pump([0])
    
            # We should see only *one* call to `_process_queue`
            self.assertEqual(len(self._pending_calls), 1)
            self.assertEqual(self._pending_calls[0][0], ["foo1", "foo2"])
            self.assertFalse(queue_d1.called)
            self.assertFalse(queue_d2.called)
    
            # Return value of the `_process_queue` should be propagated back to both.
            self._pending_calls.pop()[1].callback("bar")
    
            self.assertEqual(self.successResultOf(queue_d1), "bar")
            self.assertEqual(self.successResultOf(queue_d2), "bar")
    
        def test_queuing(self):
            """Test that we queue up requests while a `_process_queue` is being
            called.
            """
    
            self.assertFalse(self._pending_calls)
    
            queue_d1 = defer.ensureDeferred(self.queue.add_to_queue("foo1"))
            self.clock.pump([0])
    
            queue_d2 = defer.ensureDeferred(self.queue.add_to_queue("foo2"))
    
            # We should see only *one* call to `_process_queue`
            self.assertEqual(len(self._pending_calls), 1)
            self.assertEqual(self._pending_calls[0][0], ["foo1"])
            self.assertFalse(queue_d1.called)
            self.assertFalse(queue_d2.called)
    
            # Return value of the `_process_queue` should be propagated back to the
            # first.
            self._pending_calls.pop()[1].callback("bar1")
    
            self.assertEqual(self.successResultOf(queue_d1), "bar1")
            self.assertFalse(queue_d2.called)
    
            # We should now see a second call to `_process_queue`
            self.clock.pump([0])
            self.assertEqual(len(self._pending_calls), 1)
            self.assertEqual(self._pending_calls[0][0], ["foo2"])
            self.assertFalse(queue_d2.called)
    
            # Return value of the `_process_queue` should be propagated back to the
            # second.
            self._pending_calls.pop()[1].callback("bar2")
    
            self.assertEqual(self.successResultOf(queue_d2), "bar2")
    
        def test_different_keys(self):
            """Test that calls to different keys get processed in parallel."""
    
            self.assertFalse(self._pending_calls)
    
            queue_d1 = defer.ensureDeferred(self.queue.add_to_queue("foo1", key=1))
            self.clock.pump([0])
            queue_d2 = defer.ensureDeferred(self.queue.add_to_queue("foo2", key=2))
            self.clock.pump([0])
    
            # We queue up another item with key=2 to check that we will keep taking
            # things off the queue.
            queue_d3 = defer.ensureDeferred(self.queue.add_to_queue("foo3", key=2))
    
            # We should see two calls to `_process_queue`
            self.assertEqual(len(self._pending_calls), 2)
            self.assertEqual(self._pending_calls[0][0], ["foo1"])
            self.assertEqual(self._pending_calls[1][0], ["foo2"])
            self.assertFalse(queue_d1.called)
            self.assertFalse(queue_d2.called)
            self.assertFalse(queue_d3.called)
    
            # Return value of the `_process_queue` should be propagated back to the
            # first.
            self._pending_calls.pop(0)[1].callback("bar1")
    
            self.assertEqual(self.successResultOf(queue_d1), "bar1")
            self.assertFalse(queue_d2.called)
            self.assertFalse(queue_d3.called)
    
            # Return value of the `_process_queue` should be propagated back to the
            # second.
            self._pending_calls.pop()[1].callback("bar2")
    
            self.assertEqual(self.successResultOf(queue_d2), "bar2")
            self.assertFalse(queue_d3.called)
    
            # We should now see a call `_pending_calls` for `foo3`
            self.clock.pump([0])
            self.assertEqual(len(self._pending_calls), 1)
            self.assertEqual(self._pending_calls[0][0], ["foo3"])
            self.assertFalse(queue_d3.called)
    
            # Return value of the `_process_queue` should be propagated back to the
            # third deferred.
            self._pending_calls.pop()[1].callback("bar4")
    
            self.assertEqual(self.successResultOf(queue_d3), "bar4")