diff --git a/tests/test_loaders.py b/tests/test_loaders.py
index 07963737..12e543ad 100644
--- a/tests/test_loaders.py
+++ b/tests/test_loaders.py
@@ -4,7 +4,7 @@
 from __future__ import annotations
 
 import asyncio
-from datetime import datetime, timezone
+from datetime import datetime, timedelta, timezone
 
 from jupyter_collaboration.loaders import FileLoader, FileLoaderMapping
 
@@ -34,7 +34,7 @@ async def trigger():
 
     loader.observe("test", trigger)
 
-    cm.model["last_modified"] = datetime.now(timezone.utc)
+    cm.model["last_modified"] = datetime.now(timezone.utc) + timedelta(seconds=1)
 
     await asyncio.sleep(0.15)
 
@@ -66,7 +66,7 @@ async def trigger():
 
     loader.observe("test", trigger)
 
-    cm.model["last_modified"] = datetime.now(timezone.utc)
+    cm.model["last_modified"] = datetime.now(timezone.utc) + timedelta(seconds=1)
 
     await loader.maybe_notify()