diff --git a/tests/basic/test_history.py b/tests/basic/test_history.py
index c6376850d..195da0871 100644
--- a/tests/basic/test_history.py
+++ b/tests/basic/test_history.py
@@ -4,11 +4,17 @@ from aider.history import ChatSummary
 from aider.models import Model
 
 
+def count(msg):
+    if isinstance(msg, list):
+        return sum(count(m) for m in msg)
+    return len(msg["content"].split())
+
+
 class TestChatSummary(TestCase):
     def setUp(self):
         self.mock_model = mock.Mock(spec=Model)
         self.mock_model.name = "gpt-3.5-turbo"
-        self.mock_model.token_count = lambda msg: len(msg["content"].split())
+        self.mock_model.token_count = count
         self.mock_model.info = {"max_input_tokens": 4096}
         self.mock_model.simple_send_with_retries = mock.Mock()
         self.chat_summary = ChatSummary(self.mock_model, max_tokens=100)
@@ -55,8 +61,11 @@ class TestChatSummary(TestCase):
         )
 
     def test_summarize(self):
-        messages = [{"role": "user", "content": f"Message {i}"} for i in range(10)]
-        messages.extend([{"role": "assistant", "content": f"Response {i}"} for i in range(10)])
+        N = 100
+        messages = [None] * (2 * N)
+        for i in range(N):
+            messages[2 * i] = {"role": "user", "content": f"Message {i}"}
+            messages[2 * i + 1] = {"role": "assistant", "content": f"Response {i}"}
 
         with mock.patch.object(
             self.chat_summary,
@@ -65,9 +74,11 @@ class TestChatSummary(TestCase):
         ):
             result = self.chat_summary.summarize(messages)
 
+        print(result)
         self.assertIsInstance(result, list)
         self.assertGreater(len(result), 0)
-        self.assertLessEqual(len(result), len(messages))
+        self.assertLess(len(result), len(messages))
+        self.assertEqual(result[0]["content"], "Summary")
 
     def test_fallback_to_second_model(self):
         mock_model1 = mock.Mock(spec=Model)