diff --git a/tests/basic/test_reasoning.py b/tests/basic/test_reasoning.py
index 4ad9fe997..df494b570 100644
--- a/tests/basic/test_reasoning.py
+++ b/tests/basic/test_reasoning.py
@@ -121,6 +121,9 @@ class TestReasoning(unittest.TestCase):
 
         # Mock the model's send_completion to return the hash and completion
         with patch.object(model, "send_completion", return_value=(mock_hash, chunks)):
+            # Set mdstream directly on the coder object
+            coder.mdstream = mock_mdstream
+            
             # Call send with a simple message
             messages = [{"role": "user", "content": "test prompt"}]
             list(coder.send(messages))