1 files changed, 82 insertions, 0 deletions
diff --git a/tests/handlers/test_appservice.py b/tests/handlers/test_appservice.py
index 8c72cf6b30..5b0cd1ab86 100644
--- a/tests/handlers/test_appservice.py
+++ b/tests/handlers/test_appservice.py
@@ -411,6 +411,88 @@ class ApplicationServicesHandlerSendEventsTestCase(unittest.HomeserverTestCase):
             "exclusive_as_user", "password", self.exclusive_as_user_device_id
         )
 
+    def test_sending_read_receipt_batches_to_application_services(self):
+        """Tests that a large batch of read receipts are sent correctly to
+        interested application services.
+        """
+        # Register an application service that's interested in a certain user
+        # and room prefix
+        interested_appservice = self._register_application_service(
+            namespaces={
+                ApplicationService.NS_USERS: [
+                    {
+                        "regex": "@exclusive_as_user:.+",
+                        "exclusive": True,
+                    }
+                ],
+                ApplicationService.NS_ROOMS: [
+                    {
+                        "regex": "!fakeroom_.*",
+                        "exclusive": True,
+                    }
+                ],
+            },
+        )
+
+        # "Complete" a transaction.
+        # All this really does for us is make an entry in the application_services_state
+        # database table, which tracks the current stream_token per stream ID per AS.
+        self.get_success(
+            self.hs.get_datastores().main.complete_appservice_txn(
+                0,
+                interested_appservice,
+            )
+        )
+
+        # Now, pretend that we receive a large burst of read receipts (300 total) that
+        # all come in at once.
+        for i in range(300):
+            self.get_success(
+                # Insert a fake read receipt into the database
+                self.hs.get_datastores().main.insert_receipt(
+                    # We have to use unique room ID + user ID combinations here, as the db query
+                    # is an upsert.
+                    room_id=f"!fakeroom_{i}:test",
+                    receipt_type="m.read",
+                    user_id=self.local_user,
+                    event_ids=[f"$eventid_{i}"],
+                    data={},
+                )
+            )
+
+        # Now notify the appservice handler that 300 read receipts have all arrived
+        # at once. What will it do!
+        # note: stream tokens start at 2
+        for stream_token in range(2, 303):
+            self.get_success(
+                self.hs.get_application_service_handler()._notify_interested_services_ephemeral(
+                    services=[interested_appservice],
+                    stream_key="receipt_key",
+                    new_token=stream_token,
+                    users=[self.exclusive_as_user],
+                )
+            )
+
+        # Using our txn send mock, we can see what the AS received. After iterating over every
+        # transaction, we'd like to see all 300 read receipts accounted for.
+        # No more, no less.
+        all_ephemeral_events = []
+        for call in self.send_mock.call_args_list:
+            ephemeral_events = call[0][2]
+            all_ephemeral_events += ephemeral_events
+
+        # Ensure that no duplicate events were sent
+        self.assertEqual(len(all_ephemeral_events), 300)
+
+        # Check that the ephemeral event is a read receipt with the expected structure
+        latest_read_receipt = all_ephemeral_events[-1]
+        self.assertEqual(latest_read_receipt["type"], "m.receipt")
+
+        event_id = list(latest_read_receipt["content"].keys())[0]
+        self.assertEqual(
+            latest_read_receipt["content"][event_id]["m.read"], {self.local_user: {}}
+        )
+
     @unittest.override_config(
         {"experimental_features": {"msc2409_to_device_messages_enabled": True}}
     )