1 files changed, 13 insertions, 0 deletions
diff --git a/tests/events/test_utils.py b/tests/events/test_utils.py
index cf81bcf52c..975c285ec7 100644
--- a/tests/events/test_utils.py
+++ b/tests/events/test_utils.py
@@ -32,6 +32,7 @@ from synapse.events.utils import (
     PowerLevelsContent,
     SerializeEventConfig,
     _split_field,
+    clone_event,
     copy_and_fixup_power_levels_contents,
     maybe_upsert_event_field,
     prune_event,
@@ -611,6 +612,18 @@ class PruneEventTestCase(stdlib_unittest.TestCase):
         )
 
 
+class CloneEventTestCase(stdlib_unittest.TestCase):
+    def test_unsigned_is_copied(self) -> None:
+        original = make_event_from_dict(
+            {"type": "A", "event_id": "$test:domain", "unsigned": {"a": 1, "b": 2}}
+        )
+        cloned = clone_event(original)
+        cloned.unsigned["b"] = 3
+
+        self.assertEqual(original.unsigned, {"a": 1, "b": 2})
+        self.assertEqual(cloned.unsigned, {"a": 1, "b": 3})
+
+
 class SerializeEventTestCase(stdlib_unittest.TestCase):
     def serialize(self, ev: EventBase, fields: Optional[List[str]]) -> JsonDict:
         return serialize_event(