code: def test_rolling_should_empty_df():
      pivot_df = pp.pivot(
          df=single_metric_df,
          index=["dttm"],
          columns=["country"],
          aggregates={"sum_metric": {"operator": "sum"}},
      )
      rolling_df = pp.rolling(
          df=pivot_df,
          rolling_type="sum",
          window=2,
          min_periods=2,
          columns={"sum_metric": "sum_metric"},
      )
      assert rolling_df.empty is True
  
file_path: superset/tests/unit_tests/pandas_postprocessing/test_rolling.py
imports: import pandas
  import pytest
  from superset.exceptions import InvalidPostProcessingError
  from superset.utils import pandas_postprocessing
  from superset.utils.pandas_postprocessing.utils import FLAT_COLUMN_SEPARATOR
  from tests.unit_tests.fixtures.dataframes import multiple_metrics_df, single_metric_df, timeseries_df
  from tests.unit_tests.pandas_postprocessing.utils import series_to_list
label_desc: Use image node_id 3 for calling a global function with example usage: test_rolling_should_empty_df() without return types