add msg

Author: litang99

pandas/tests/dtypes/test_dtypes.py

@@ -1265,7 +1265,7 @@ def test_dt_to_pydatetime_conversion():
 
     df = pd.DataFrame({"ts": [pd.Timestamp("2024-01-01 12:00:00").as_unit("ns")]})
     df["ts"] = df.ts.dt.to_pydatetime()
-    assert df["ts"].dtype == expected
+    assert df["ts"].dtype == expected, f"actual={df['ts'].dtype}, expected={expected}"
 
     buffer = io.StringIO()
     with redirect_stdout(buffer):