code: def test_truncate_index_only_one_unique_value(self, frame_or_series):
      # GH 42365
      obj = Series(
          0, index=date_range("2021-06-30", "2021-06-30")
      ).repeat(5)
      if frame_or_series is DataFrame:
          obj = obj.to_frame(name="a")
  
      truncated = obj.truncate("2021-06-28", "2021-07-01")
  
      tm.assert_equal(truncated, obj)
  
file_path: pandas/pandas/tests/frame/methods/test_truncate.py
imports: import numpy
  import pytest
  import pandas
  from pandas import DataFrame, DatetimeIndex, Index, Series, date_range
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestDataFrameTruncate obj's underlying member method code with example usage: obj.test_truncate_index_only_one_unique_value(frame_or_series) without return types