Fix bug where sync could get stuck when using workers (#17438)

This is because we serialized the token wrong if the instance map
contained entries from before the minimum token.

1 files changed, 71 insertions, 0 deletions

diff --git a/tests/test_types.py b/tests/test_types.py
index 944aa784fc..00adc65a5a 100644
--- a/tests/test_types.py
+++ b/tests/test_types.py
@@ -19,9 +19,18 @@
 #
 #
 
+from typing import Type
+from unittest import skipUnless
+
+from immutabledict import immutabledict
+from parameterized import parameterized_class
+
 from synapse.api.errors import SynapseError
 from synapse.types import (
+    AbstractMultiWriterStreamToken,
+    MultiWriterStreamToken,
     RoomAlias,
+    RoomStreamToken,
     UserID,
     get_domain_from_id,
     get_localpart_from_id,
@@ -29,6 +38,7 @@ from synapse.types import (
 )
 
 from tests import unittest
+from tests.utils import USE_POSTGRES_FOR_TESTS
 
 
 class IsMineIDTests(unittest.HomeserverTestCase):
@@ -127,3 +137,64 @@ class MapUsernameTestCase(unittest.TestCase):
         # this should work with either a unicode or a bytes
         self.assertEqual(map_username_to_mxid_localpart("têst"), "t=c3=aast")
         self.assertEqual(map_username_to_mxid_localpart("têst".encode()), "t=c3=aast")
+
+
+@parameterized_class(
+    ("token_type",),
+    [
+        (MultiWriterStreamToken,),
+        (RoomStreamToken,),
+    ],
+    class_name_func=lambda cls, num, params_dict: f"{cls.__name__}_{params_dict['token_type'].__name__}",
+)
+class MultiWriterTokenTestCase(unittest.HomeserverTestCase):
+    """Tests for the different types of multi writer tokens."""
+
+    token_type: Type[AbstractMultiWriterStreamToken]
+
+    def test_basic_token(self) -> None:
+        """Test that a simple stream token can be serialized and unserialized"""
+        store = self.hs.get_datastores().main
+
+        token = self.token_type(stream=5)
+
+        string_token = self.get_success(token.to_string(store))
+
+        if isinstance(token, RoomStreamToken):
+            self.assertEqual(string_token, "s5")
+        else:
+            self.assertEqual(string_token, "5")
+
+        parsed_token = self.get_success(self.token_type.parse(store, string_token))
+        self.assertEqual(parsed_token, token)
+
+    @skipUnless(USE_POSTGRES_FOR_TESTS, "Requires Postgres")
+    def test_instance_map(self) -> None:
+        """Test for stream token with instance map"""
+        store = self.hs.get_datastores().main
+
+        token = self.token_type(stream=5, instance_map=immutabledict({"foo": 6}))
+
+        string_token = self.get_success(token.to_string(store))
+        self.assertEqual(string_token, "m5~1.6")
+
+        parsed_token = self.get_success(self.token_type.parse(store, string_token))
+        self.assertEqual(parsed_token, token)
+
+    def test_instance_map_assertion(self) -> None:
+        """Test that we assert values in the instance map are greater than the
+        min stream position"""
+
+        with self.assertRaises(ValueError):
+            self.token_type(stream=5, instance_map=immutabledict({"foo": 4}))
+
+        with self.assertRaises(ValueError):
+            self.token_type(stream=5, instance_map=immutabledict({"foo": 5}))
+
+    def test_parse_bad_token(self) -> None:
+        """Test that we can parse tokens produced by a bug in Synapse of the
+        form `m5~`"""
+        store = self.hs.get_datastores().main
+
+        parsed_token = self.get_success(self.token_type.parse(store, "m5~"))
+        self.assertEqual(parsed_token, self.token_type(stream=5))