diff --git a/pandas/tests/apply/test_frame_apply.py b/pandas/tests/apply/test_frame_apply.py index c7eb8c0332e84..f0f8b3befadcb 100644 --- a/pandas/tests/apply/test_frame_apply.py +++ b/pandas/tests/apply/test_frame_apply.py @@ -1665,3 +1665,15 @@ def foo2(x, b=2, c=0): columns=MultiIndex.from_tuples([("x", "foo1"), ("x", "foo2")]), ) tm.assert_frame_equal(result, expected) + + +def test_agg_std(): + df = DataFrame(np.arange(6).reshape(3, 2), columns=["A", "B"]) + + result = df.agg(np.std) + expected = Series({"A": 2.0, "B": 2.0}, dtype=float) + tm.assert_series_equal(result, expected) + + result = df.agg([np.std]) + expected = DataFrame({"A": 2.0, "B": 2.0}, index=["std"]) + tm.assert_frame_equal(result, expected)