code: def test_ceil_floor_edge(self, test_input, rounder, freq, expected):
      dt = Timestamp(test_input)
      func = getattr(dt, rounder)
      result = func(freq)
  
      if dt is NaT:
          assert result is NaT
      else:
          expected = Timestamp(expected)
          assert result == expected
  
imports: from hypothesis import given, strategies
  import numpy
  import pytest
  import pytz
  from pandas._libs import lib
  from pandas._libs.tslibs import NaT, OutOfBoundsDatetime, Timedelta, Timestamp, iNaT, to_offset
  from pandas._libs.tslibs.dtypes import NpyDatetimeUnit
  from pandas._libs.tslibs.period import INVALID_FREQ_ERR_MSG
  import pandas._testing
label_desc: Use image node_id 8 for calling the TestTimestampRound obj's underlying member method code with example usage: obj.test_ceil_floor_edge(test_input, rounder, freq, expected) without return types