code: def test_rolling_getitem():
      pdf = pd.DataFrame({"a": [1, 2, 3, 4], "b": [1, 2, 3, 4]})
      gdf = cudf.from_pandas(pdf)
  
      assert_eq(
          pdf.rolling(2)["a"].sum().fillna(-1),
          gdf.rolling(2)["a"].sum().fillna(-1),
          check_dtype=False,
      )
      assert_eq(
          pdf.rolling(2)["a", "b"].sum().fillna(-1),
          gdf.rolling(2)["a", "b"].sum().fillna(-1),
          check_dtype=False,
      )
      assert_eq(
          pdf.rolling(2)[["a", "b"]].sum().fillna(-1),
          gdf.rolling(2)["a", "b"].sum().fillna(-1),
          check_dtype=False,
      )
  
imports: import math
  from contextlib import contextmanager
  import numpy
  import pandas
  import pytest
  import cudf
  from cudf.core._compat import PANDAS_GE_150
  from cudf.testing._utils import _create_pandas_series_float64_default, assert_eq
  from cudf.testing.dataset_generator import rand_dataframe
label_desc: Use image node_id 9 for calling a global function with example usage: test_rolling_getitem() without return types