code: def test_truncate_all_data_points(self):
      tds = self.market_opens.index
      days = tds[
          tds.slice_indexer(
              start=self.test_calendar_start + 1,
              end=self.test_calendar_start + 3,
          )
      ]
      minutes = DatetimeIndex(
          [
              self.market_opens[days[0]] + timedelta(minutes=60),
              self.market_opens[days[1]] + timedelta(minutes=120),
          ]
      )
      sid = 1
      data = DataFrame(
          data={
              "open": [10.0, 11.0],
              "high": [20.0, 21.0],
              "low": [30.0, 31.0],
              "close": [40.0, 41.0],
              "volume": [50.0, 51.0],
          },
          index=minutes,
      )
      self.writer.write_sid(sid, data)
  
      # Truncate to first day in the calendar, a day before the first
      # day with minute data.
      self.writer.truncate(self.test_calendar_start)
  
      # Refresh the reader since truncate update the metadata.
      self.reader = BcolzMinuteBarReader(self.dest)
  
      self.assertEqual(
          self.writer.last_date_in_output_for_sid(sid),
          self.test_calendar_start,
      )
  
      cal = self.trading_calendar
      _, last_close = cal.open_and_close_for_session(
          self.test_calendar_start
      )
      self.assertEqual(self.reader.last_available_dt, last_close)
  
imports: from datetime import timedelta
  import os
  from numpy import arange, array, int64, float64, full, nan, transpose, zeros
  from numpy.testing import assert_almost_equal, assert_array_equal
  from pandas import DataFrame, DatetimeIndex, Timestamp, Timedelta, NaT, date_range
  from zipline.data.bar_reader import NoDataForSid, NoDataOnDate
  from zipline.data.minute_bars import BcolzMinuteBarMetadata, BcolzMinuteBarWriter, BcolzMinuteBarReader, BcolzMinuteOverlappingData, US_EQUITIES_MINUTES_PER_DAY, BcolzMinuteWriterColumnMismatch, H5MinuteBarUpdateWriter, H5MinuteBarUpdateReader
  from zipline.testing.fixtures import WithAssetFinder, WithInstanceTmpDir, WithTradingCalendars, ZiplineTestCase
label_desc: Use image node_id 27 for calling the BcolzMinuteBarTestCase obj's underlying member method code with example usage: obj.test_truncate_all_data_points() without return types