code: def test_to_timestamp(self, frame_or_series):
      K = 5
      index = period_range(freq="Y", start="1/1/2001", end="12/1/2009")
      obj = DataFrame(
          np.random.default_rng(2).standard_normal((len(index), K)),
          index=index,
          columns=["A", "B", "C", "D", "E"],
      )
      obj["mix"] = "a"
      obj = tm.get_obj(obj, frame_or_series)
  
      exp_index = date_range(
          "1/1/2001", end="12/31/2009", freq="YE-DEC"
      )
      exp_index = exp_index + Timedelta(1, "D") - Timedelta(1, "ns")
      result = obj.to_timestamp("D", "end")
      tm.assert_index_equal(result.index, exp_index)
      tm.assert_numpy_array_equal(result.values, obj.values)
      if frame_or_series is Series:
          assert result.name == "A"
  
      exp_index = date_range("1/1/2001", end="1/1/2009", freq="YS-JAN")
      result = obj.to_timestamp("D", "start")
      tm.assert_index_equal(result.index, exp_index)
  
      result = obj.to_timestamp(how="start")
      tm.assert_index_equal(result.index, exp_index)
  
      delta = timedelta(hours=23)
      result = obj.to_timestamp("H", "end")
      exp_index = _get_with_delta(delta)
      exp_index = exp_index + Timedelta(1, "h") - Timedelta(1, "ns")
      tm.assert_index_equal(result.index, exp_index)
  
      delta = timedelta(hours=23, minutes=59)
      result = obj.to_timestamp("T", "end")
      exp_index = _get_with_delta(delta)
      exp_index = exp_index + Timedelta(1, "m") - Timedelta(1, "ns")
      tm.assert_index_equal(result.index, exp_index)
  
      result = obj.to_timestamp("S", "end")
      delta = timedelta(hours=23, minutes=59, seconds=59)
      exp_index = _get_with_delta(delta)
      exp_index = exp_index + Timedelta(1, "s") - Timedelta(1, "ns")
      tm.assert_index_equal(result.index, exp_index)
  
file_path: pandas/pandas/tests/frame/methods/test_to_timestamp.py
imports: from datetime import timedelta
  import numpy
  import pytest
  from pandas import DataFrame, DatetimeIndex, PeriodIndex, Series, Timedelta, date_range, period_range, to_datetime
  import pandas._testing
label_desc: Use image node_id 1 for calling the TestToTimestamp obj's underlying member method code with example usage: obj.test_to_timestamp(frame_or_series) without return types