diff --git a/tests/rest/client/test_sync.py b/tests/rest/client/test_sync.py
index f923c14b9f..a20a3fb40d 100644
--- a/tests/rest/client/test_sync.py
+++ b/tests/rest/client/test_sync.py
@@ -34,7 +34,7 @@ from synapse.api.constants import (
 )
 from synapse.rest.client import devices, knock, login, read_marker, receipts, room, sync
 from synapse.server import HomeServer
-from synapse.types import JsonDict
+from synapse.types import JsonDict, RoomStreamToken, StreamKeyType
 from synapse.util import Clock
 
 from tests import unittest
@@ -1227,6 +1227,8 @@ class SlidingSyncTestCase(unittest.HomeserverTestCase):
 
     def prepare(self, reactor: MemoryReactor, clock: Clock, hs: HomeServer) -> None:
         self.sync_endpoint = "/_matrix/client/unstable/org.matrix.msc3575/sync"
+        self.store = hs.get_datastores().main
+        self.event_sources = hs.get_event_sources()
 
     def test_sync_list(self) -> None:
         """
@@ -1280,3 +1282,57 @@ class SlidingSyncTestCase(unittest.HomeserverTestCase):
             ],
             channel.json_body["lists"]["foo-list"],
         )
+
+    def test_wait_for_sync_token(self) -> None:
+        """
+        Test that worker will wait until it catches up to the given token
+        """
+        alice_user_id = self.register_user("alice", "correcthorse")
+        alice_access_token = self.login(alice_user_id, "correcthorse")
+
+        # Create a future token that will cause us to wait. Since we never send a new
+        # event to reach that future stream_ordering, the worker will wait until the
+        # full timeout.
+        current_token = self.event_sources.get_current_token()
+        future_position_token = current_token.copy_and_replace(
+            StreamKeyType.ROOM,
+            RoomStreamToken(stream=current_token.room_key.stream + 1),
+        )
+
+        future_position_token_serialized = self.get_success(
+            future_position_token.to_string(self.store)
+        )
+
+        # Make the Sliding Sync request
+        channel = self.make_request(
+            "POST",
+            self.sync_endpoint + f"?pos={future_position_token_serialized}",
+            {
+                "lists": {
+                    "foo-list": {
+                        "ranges": [[0, 99]],
+                        "sort": ["by_notification_level", "by_recency", "by_name"],
+                        "required_state": [
+                            ["m.room.join_rules", ""],
+                            ["m.room.history_visibility", ""],
+                            ["m.space.child", "*"],
+                        ],
+                        "timeline_limit": 1,
+                    }
+                }
+            },
+            access_token=alice_access_token,
+            await_result=False,
+        )
+        # Block for 10 seconds to make `notifier.wait_for_stream_token(from_token)`
+        # timeout
+        with self.assertRaises(TimedOutException):
+            channel.await_result(timeout_ms=9900)
+        channel.await_result(timeout_ms=200)
+        self.assertEqual(channel.code, 200, channel.json_body)
+
+        # We expect the `next_pos` in the result to be the same as what we requested
+        # with because we weren't able to find anything new yet.
+        self.assertEqual(
+            channel.json_body["next_pos"], future_position_token_serialized
+        )