test: adjust rolling_exp test to avoid re-assigning pandas_array for …

…compatibility with pandas < 2.2.0 pandas ewm can work with non-ns resolution from >= 2.2.0. Here we just test that this PR rolling_exp can work with non-ns resolution.
pydata · abiasiol · Apr 19, 2025 · Apr 19, 2025 · Apr 19, 2025 · Apr 20, 2025
commit e2c41e03f47ac409e206a5f111c7b75ae4e20b4b
diff --git a/xarray/tests/test_rolling.py b/xarray/tests/test_rolling.py
@@ -555,10 +555,9 @@ def test_rolling_exp_mean_pandas_halflife(self, da, window) -> None:
         # test with different time units (ms -> s)
         da["time"] = da.get_index("time").astype("datetime64[s]")
         result = da.rolling_exp(window_type=window_type, **{dim: window}).mean()
-        pandas_array = da.to_pandas()
-        expected = xr.DataArray(
-            pandas_array.ewm(**{window_type: window}, times=pandas_array.index).mean()
-        ).transpose(*da.dims)
+
+        # pandas < 2.2.0 does not support non-ns resolution for ewm
+        # so let's not re-assign pandas_array
         assert_allclose(expected.variable, result.variable)
 
     @pytest.mark.parametrize("backend", ["numpy"], indirect=True)