Clear event caches when we purge history (#15609)

This should help a little with #13476

---------

Co-authored-by: Patrick Cloke <patrickc@matrix.org>

3 files changed, 5 insertions, 8 deletions

diff --git a/tests/handlers/test_sync.py b/tests/handlers/test_sync.py

index 0d9a3de92a..9f035a02dc 100644
--- a/tests/handlers/test_sync.py
+++ b/tests/handlers/test_sync.py
@@ -163,7 +163,7 @@ class SyncTestCase(tests.unittest.HomeserverTestCase):
         # Blow away caches (supported room versions can only change due to a restart).
         self.store.get_rooms_for_user_with_stream_ordering.invalidate_all()
         self.store.get_rooms_for_user.invalidate_all()
-        self.get_success(self.store._get_event_cache.clear())
+        self.store._get_event_cache.clear()
         self.store._event_ref.clear()
 
         # The rooms should be excluded from the sync response.
diff --git a/tests/rest/client/test_read_marker.py b/tests/rest/client/test_read_marker.py

index 0eedcdb476..5cdd5694a0 100644
--- a/tests/rest/client/test_read_marker.py
+++ b/tests/rest/client/test_read_marker.py
@@ -131,9 +131,6 @@ class ReadMarkerTestCase(unittest.HomeserverTestCase):
         event = self.get_success(self.store.get_event(event_id_1, allow_none=True))
         assert event is None
 
-        # TODO See https://github.com/matrix-org/synapse/issues/13476
-        self.store.get_event_ordering.invalidate_all()
-
         # Test moving the read marker to a newer event
         event_id_2 = send_message()
         channel = self.make_request(
diff --git a/tests/storage/databases/main/test_events_worker.py b/tests/storage/databases/main/test_events_worker.py

index 9606ecc43b..788500e38f 100644
--- a/tests/storage/databases/main/test_events_worker.py
+++ b/tests/storage/databases/main/test_events_worker.py
@@ -188,7 +188,7 @@ class EventCacheTestCase(unittest.HomeserverTestCase):
         self.event_id = res["event_id"]
 
         # Reset the event cache so the tests start with it empty
-        self.get_success(self.store._get_event_cache.clear())
+        self.store._get_event_cache.clear()
 
     def test_simple(self) -> None:
         """Test that we cache events that we pull from the DB."""
@@ -205,7 +205,7 @@ class EventCacheTestCase(unittest.HomeserverTestCase):
         """
 
         # Reset the event cache
-        self.get_success(self.store._get_event_cache.clear())
+        self.store._get_event_cache.clear()
 
         with LoggingContext("test") as ctx:
             # We keep hold of the event event though we never use it.
@@ -215,7 +215,7 @@ class EventCacheTestCase(unittest.HomeserverTestCase):
             self.assertEqual(ctx.get_resource_usage().evt_db_fetch_count, 1)
 
         # Reset the event cache
-        self.get_success(self.store._get_event_cache.clear())
+        self.store._get_event_cache.clear()
 
         with LoggingContext("test") as ctx:
             self.get_success(self.store.get_event(self.event_id))
@@ -390,7 +390,7 @@ class GetEventCancellationTestCase(unittest.HomeserverTestCase):
         self.event_id = res["event_id"]
 
         # Reset the event cache so the tests start with it empty
-        self.get_success(self.store._get_event_cache.clear())
+        self.store._get_event_cache.clear()
 
     @contextmanager
     def blocking_get_event_calls(