diff --git a/synapse/tests/test_common.py b/synapse/tests/test_common.py
index 4aa0d2219f9..bf401bcc5bb 100644
--- a/synapse/tests/test_common.py
+++ b/synapse/tests/test_common.py
@@ -183,11 +183,11 @@ def test_common_chunks(self):
             parts = [chunk for chunk in s_common.chunks({1, 2, 3}, 10000)]
 
         # dict is unslicable
-        with self.assertRaises(TypeError) as cm:
+        with self.assertRaises((TypeError, KeyError)) as cm:
             parts = [chunk for chunk in s_common.chunks({1: 2}, 10000)]
 
         # empty dict is caught during the [0:0] slice
-        with self.assertRaises(TypeError) as cm:
+        with self.assertRaises((TypeError, KeyError)) as cm:
             parts = [chunk for chunk in s_common.chunks({}, 10000)]
 
     def test_common_ehex_uhex(self):