Wait for lazy join to complete when getting current state (#12872)

1 files changed, 58 insertions, 1 deletions

diff --git a/tests/storage/util/test_partial_state_events_tracker.py b/tests/storage/util/test_partial_state_events_tracker.py
index 303e190b6c..cae14151c0 100644
--- a/tests/storage/util/test_partial_state_events_tracker.py
+++ b/tests/storage/util/test_partial_state_events_tracker.py
@@ -17,8 +17,12 @@ from unittest import mock
 
 from twisted.internet.defer import CancelledError, ensureDeferred
 
-from synapse.storage.util.partial_state_events_tracker import PartialStateEventsTracker
+from synapse.storage.util.partial_state_events_tracker import (
+    PartialCurrentStateTracker,
+    PartialStateEventsTracker,
+)
 
+from tests.test_utils import make_awaitable
 from tests.unittest import TestCase
 
 
@@ -115,3 +119,56 @@ class PartialStateEventsTrackerTestCase(TestCase):
 
         self.tracker.notify_un_partial_stated("event1")
         self.successResultOf(d2)
+
+
+class PartialCurrentStateTrackerTestCase(TestCase):
+    def setUp(self) -> None:
+        self.mock_store = mock.Mock(spec_set=["is_partial_state_room"])
+
+        self.tracker = PartialCurrentStateTracker(self.mock_store)
+
+    def test_does_not_block_for_full_state_rooms(self):
+        self.mock_store.is_partial_state_room.return_value = make_awaitable(False)
+
+        self.successResultOf(ensureDeferred(self.tracker.await_full_state("room_id")))
+
+    def test_blocks_for_partial_room_state(self):
+        self.mock_store.is_partial_state_room.return_value = make_awaitable(True)
+
+        d = ensureDeferred(self.tracker.await_full_state("room_id"))
+
+        # there should be no result yet
+        self.assertNoResult(d)
+
+        # notifying that the room has been de-partial-stated should unblock
+        self.tracker.notify_un_partial_stated("room_id")
+        self.successResultOf(d)
+
+    def test_un_partial_state_race(self):
+        # We should correctly handle race between awaiting the state and us
+        # un-partialling the state
+        async def is_partial_state_room(events):
+            self.tracker.notify_un_partial_stated("room_id")
+            return True
+
+        self.mock_store.is_partial_state_room.side_effect = is_partial_state_room
+
+        self.successResultOf(ensureDeferred(self.tracker.await_full_state("room_id")))
+
+    def test_cancellation(self):
+        self.mock_store.is_partial_state_room.return_value = make_awaitable(True)
+
+        d1 = ensureDeferred(self.tracker.await_full_state("room_id"))
+        self.assertNoResult(d1)
+
+        d2 = ensureDeferred(self.tracker.await_full_state("room_id"))
+        self.assertNoResult(d2)
+
+        d1.cancel()
+        self.assertFailure(d1, CancelledError)
+
+        # d2 should still be waiting!
+        self.assertNoResult(d2)
+
+        self.tracker.notify_un_partial_stated("room_id")
+        self.successResultOf(d2)