code: def test_get_single_event_df():
      """Tests get a single event df from a single holiday."""
      holiday1 = ("US", "Christmas Day_-2")
      holiday2 = ("US", "Christmas Day_+0")
      holiday3 = ("US", "Christmas Day_+1")
      hi = HolidayInferrer()
      hi.infer_holidays(
          df=pd.DataFrame(
              {
                  TIME_COL: pd.date_range(
                      "2020-01-01", freq="D", periods=731
                  ),
                  VALUE_COL: 1,
              }
          )
      )
      df1 = hi._get_event_df_for_single_event(
          holiday=holiday1, country_holiday_df=hi.country_holiday_df
      )
      df2 = hi._get_event_df_for_single_event(
          holiday=holiday2, country_holiday_df=hi.country_holiday_df
      )
      df3 = hi._get_event_df_for_single_event(
          holiday=holiday3, country_holiday_df=hi.country_holiday_df
      )
      assert df1.equals(
          pd.DataFrame(
              {
                  EVENT_DF_DATE_COL: pd.to_datetime(
                      ["2020-12-23", "2021-12-22", "2022-12-24"]
                  ),
                  EVENT_DF_LABEL_COL: "US_Christmas Day_minus_2",
              }
          )
      )
      assert df2.equals(
          pd.DataFrame(
              {
                  EVENT_DF_DATE_COL: pd.to_datetime(
                      ["2020-12-25", "2021-12-24", "2022-12-26"]
                  ),
                  EVENT_DF_LABEL_COL: "US_Christmas Day",
              }
          )
      )
      assert df3.equals(
          pd.DataFrame(
              {
                  EVENT_DF_DATE_COL: pd.to_datetime(
                      ["2020-12-26", "2021-12-25", "2022-12-27"]
                  ),
                  EVENT_DF_LABEL_COL: "US_Christmas Day_plus_1",
              }
          )
      )
  
imports: import numpy
  import pandas
  import pytest
  from holidays_ext.get_holidays import get_holiday_df
  from testfixtures import LogCapture
  from greykite.algo.common.holiday_inferrer import HolidayInferrer
  from greykite.common.constants import EVENT_DF_DATE_COL
  from greykite.common.constants import EVENT_DF_LABEL_COL
  from greykite.common.constants import TIME_COL
  from greykite.common.constants import VALUE_COL
  from greykite.common.data_loader import DataLoader
  from greykite.common.logging import LOGGER_NAME
label_desc: Use image node_id 12 for calling a global function with example usage: test_get_single_event_df() without return types