Use a predefined fixture function for tz parameterization thanks to @mroeschke

Author: noritada

pandas/tests/groupby/test_groupby.py

@@ -1884,7 +1884,6 @@ def test_groupby_axis_1(group_name):
     assert_frame_equal(results, expected)
 
 
-@pytest.mark.parametrize("tz", [None, "Asia/Tokyo"])
 @pytest.mark.parametrize(
     "op, expected",
     [
@@ -1929,8 +1928,9 @@ def test_groupby_axis_1(group_name):
         ),
     ],
 )
-def test_shift_bfill_ffill_tz(tz, op, expected):
+def test_shift_bfill_ffill_tz(tz_naive_fixture, op, expected):
     # GH27992: Check that timezone does not drop in shift, bfill, and ffill
+    tz = tz_naive_fixture
     data = {
         "id": ["A", "B", "A", "B", "A", "B"],
         "time": [