diff --git a/tests/federation/test_federation_catch_up.py b/tests/federation/test_federation_catch_up.py
new file mode 100644
index 0000000000..73c51c9d6c
--- /dev/null
+++ b/tests/federation/test_federation_catch_up.py
@@ -0,0 +1,82 @@
+from mock import Mock
+
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+
+from tests.test_utils import event_injection, make_awaitable
+from tests.unittest import FederatingHomeserverTestCase, override_config
+
+
+class FederationCatchUpTestCases(FederatingHomeserverTestCase):
+ servlets = [
+ admin.register_servlets,
+ room.register_servlets,
+ login.register_servlets,
+ ]
+
+ def make_homeserver(self, reactor, clock):
+ return self.setup_test_homeserver(
+ federation_transport_client=Mock(spec=["send_transaction"]),
+ )
+
+ def prepare(self, reactor, clock, hs):
+ # stub out get_current_hosts_in_room
+ state_handler = hs.get_state_handler()
+
+ # This mock is crucial for destination_rooms to be populated.
+ state_handler.get_current_hosts_in_room = Mock(
+ return_value=make_awaitable(["test", "host2"])
+ )
+
+ def get_destination_room(self, room: str, destination: str = "host2") -> dict:
+ """
+ Gets the destination_rooms entry for a (destination, room_id) pair.
+
+ Args:
+ room: room ID
+ destination: what destination, default is "host2"
+
+ Returns:
+ Dictionary of { event_id: str, stream_ordering: int }
+ """
+ event_id, stream_ordering = self.get_success(
+ self.hs.get_datastore().db_pool.execute(
+ "test:get_destination_rooms",
+ None,
+ """
+ SELECT event_id, stream_ordering
+ FROM destination_rooms dr
+ JOIN events USING (stream_ordering)
+ WHERE dr.destination = ? AND dr.room_id = ?
+ """,
+ destination,
+ room,
+ )
+ )[0]
+ return {"event_id": event_id, "stream_ordering": stream_ordering}
+
+ @override_config({"send_federation": True})
+ def test_catch_up_destination_rooms_tracking(self):
+ """
+ Tests that we populate the `destination_rooms` table as needed.
+ """
+ self.register_user("u1", "you the one")
+ u1_token = self.login("u1", "you the one")
+ room = self.helper.create_room_as("u1", tok=u1_token)
+
+ self.get_success(
+ event_injection.inject_member_event(self.hs, room, "@user:host2", "join")
+ )
+
+ event_id_1 = self.helper.send(room, "wombats!", tok=u1_token)["event_id"]
+
+ row_1 = self.get_destination_room(room)
+
+ event_id_2 = self.helper.send(room, "rabbits!", tok=u1_token)["event_id"]
+
+ row_2 = self.get_destination_room(room)
+
+ # check: events correctly registered in order
+ self.assertEqual(row_1["event_id"], event_id_1)
+ self.assertEqual(row_2["event_id"], event_id_2)
+ self.assertEqual(row_1["stream_ordering"], row_2["stream_ordering"] - 1)
|