code: def test_no_rounding_occurs(self, tz_naive_fixture):
      # GH 21262
      tz = tz_naive_fixture
      rng = date_range(
          start="2016-01-01", periods=5, freq="2Min", tz=tz
      )
  
      expected_rng = DatetimeIndex(
          [
              Timestamp("2016-01-01 00:00:00", tz=tz),
              Timestamp("2016-01-01 00:02:00", tz=tz),
              Timestamp("2016-01-01 00:04:00", tz=tz),
              Timestamp("2016-01-01 00:06:00", tz=tz),
              Timestamp("2016-01-01 00:08:00", tz=tz),
          ]
      ).as_unit("ns")
  
      result = rng.round(freq="2min")
      tm.assert_index_equal(result, expected_rng)
  
file_path: pandas/pandas/tests/indexes/datetimes/methods/test_round.py
imports: import pytest
  from pandas._libs.tslibs import to_offset
  from pandas._libs.tslibs.offsets import INVALID_FREQ_ERR_MSG
  from pandas import DatetimeIndex, Timestamp, date_range
  import pandas._testing
label_desc: Use image node_id 7 for calling the TestDatetimeIndexRound obj's underlying member method code with example usage: obj.test_no_rounding_occurs(tz_naive_fixture) without return types