From 0869a4f20b810bcb96054ac27e1ca91dee9834aa Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 6 Oct 2020 17:20:15 +0100
Subject: [PATCH] Add unit test

---
 tests/handlers/test_message.py | 117 +++++++++++++++++++++++++++++++++
 1 file changed, 117 insertions(+)
 create mode 100644 tests/handlers/test_message.py

diff --git a/tests/handlers/test_message.py b/tests/handlers/test_message.py
new file mode 100644
index 0000000000..f958f30796
--- /dev/null
+++ b/tests/handlers/test_message.py
@@ -0,0 +1,117 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import logging
+
+from synapse.api.constants import EventTypes
+from synapse.rest import admin
+from synapse.rest.client.v1 import login, room
+from synapse.types import create_requester
+
+from tests import unittest
+
+logger = logging.getLogger(__name__)
+
+
+class EventCreationTestCase(unittest.HomeserverTestCase):
+    servlets = [
+        admin.register_servlets,
+        login.register_servlets,
+        room.register_servlets,
+    ]
+
+    def test_duplicated_txn_id(self):
+        """Test that attempting to handle/persist an event with a transaction ID
+        that has already been persisted correctly returns the old event and does
+        *not* produce duplicate messages.
+        """
+
+        handler = self.hs.get_event_creation_handler()
+        persist_event_storage = self.hs.get_storage().persistence
+
+        user_id = self.register_user("tester", "foobar")
+        access_token = self.login("tester", "foobar")
+        room_id = self.helper.create_room_as(user_id, tok=access_token)
+
+        # We make the IDs up here, which is fine.
+        token_id = 4957834
+        txn_id = "something_suitably_random"
+
+        requester = create_requester(user_id, access_token_id=token_id)
+
+        def create_duplicate_event():
+            return self.get_success(
+                handler.create_event(
+                    requester,
+                    {
+                        "type": EventTypes.Message,
+                        "room_id": room_id,
+                        "sender": requester.user.to_string(),
+                        "content": {"msgtype": "m.text", "body": "Hello"},
+                    },
+                    token_id=4957834,
+                    txn_id=txn_id,
+                )
+            )
+
+        event1, context = create_duplicate_event()
+
+        ret_event1, stream_id1 = self.get_success(
+            handler.handle_new_client_event(requester, event1, context)
+        )
+
+        self.assertEqual(event1.event_id, ret_event1.event_id)
+
+        event2, context = create_duplicate_event()
+
+        # We want to test that the deduplication at the persit event end works,
+        # so we want to make sure we test with different events.
+        self.assertNotEqual(event1.event_id, event2.event_id)
+
+        ret_event2, stream_id2 = self.get_success(
+            handler.handle_new_client_event(requester, event2, context)
+        )
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event2.event_id)
+        self.assertEqual(stream_id1, stream_id2)
+
+        # Let's test that calling `persist_event` directly also does the right
+        # thing.
+        event3, context = create_duplicate_event()
+        self.assertNotEqual(event1.event_id, event3.event_id)
+
+        ret_event3, event_pos3, _ = self.get_success(
+            persist_event_storage.persist_event(event3, context)
+        )
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event3.event_id)
+        self.assertEqual(stream_id1, event_pos3.stream)
+
+        # Let's test that calling `persist_events` directly also does the right
+        # thing.
+        event4, context = create_duplicate_event()
+        self.assertNotEqual(event1.event_id, event3.event_id)
+
+        events, _ = self.get_success(
+            persist_event_storage.persist_events([(event3, context)])
+        )
+        ret_event4 = events[0]
+
+        # Assert that the returned values match those from the initial event
+        # rather than the new one.
+        self.assertEqual(ret_event1.event_id, ret_event4.event_id)