1 files changed, 49 insertions, 0 deletions
diff --git a/tests/federation/test_federation_catch_up.py b/tests/federation/test_federation_catch_up.py
index 6f96cd7940..95eac6a5a3 100644
--- a/tests/federation/test_federation_catch_up.py
+++ b/tests/federation/test_federation_catch_up.py
@@ -2,6 +2,7 @@ from typing import List, Tuple
 
 from mock import Mock
 
+from synapse.api.constants import EventTypes
 from synapse.events import EventBase
 from synapse.federation.sender import PerDestinationQueue, TransactionManager
 from synapse.federation.units import Edu
@@ -421,3 +422,51 @@ class FederationCatchUpTestCases(FederatingHomeserverTestCase):
         self.assertNotIn("zzzerver", woken)
         # - all destinations are woken exactly once; they appear once in woken.
         self.assertCountEqual(woken, server_names[:-1])
+
+    @override_config({"send_federation": True})
+    def test_not_latest_event(self):
+        """Test that we send the latest event in the room even if its not ours."""
+
+        per_dest_queue, sent_pdus = self.make_fake_destination_queue()
+
+        # Make a room with a local user, and two servers. One will go offline
+        # and one will send some events.
+        self.register_user("u1", "you the one")
+        u1_token = self.login("u1", "you the one")
+        room_1 = self.helper.create_room_as("u1", tok=u1_token)
+
+        self.get_success(
+            event_injection.inject_member_event(self.hs, room_1, "@user:host2", "join")
+        )
+        event_1 = self.get_success(
+            event_injection.inject_member_event(self.hs, room_1, "@user:host3", "join")
+        )
+
+        # First we send something from the local server, so that we notice the
+        # remote is down and go into catchup mode.
+        self.helper.send(room_1, "you hear me!!", tok=u1_token)
+
+        # Now simulate us receiving an event from the still online remote.
+        event_2 = self.get_success(
+            event_injection.inject_event(
+                self.hs,
+                type=EventTypes.Message,
+                sender="@user:host3",
+                room_id=room_1,
+                content={"msgtype": "m.text", "body": "Hello"},
+            )
+        )
+
+        self.get_success(
+            self.hs.get_datastore().set_destination_last_successful_stream_ordering(
+                "host2", event_1.internal_metadata.stream_ordering
+            )
+        )
+
+        self.get_success(per_dest_queue._catch_up_transmission_loop())
+
+        # We expect only the last message from the remote, event_2, to have been
+        # sent, rather than the last *local* event that was sent.
+        self.assertEqual(len(sent_pdus), 1)
+        self.assertEqual(sent_pdus[0].event_id, event_2.event_id)
+        self.assertFalse(per_dest_queue._catching_up)