content: from datetime import datetime, timedelta
  
  import numpy as np
  import pytest
  
  from pandas._libs.tslibs import frequencies as libfrequencies, resolution
  from pandas._libs.tslibs.ccalendar import MONTHS
  from pandas._libs.tslibs.frequencies import (
      INVALID_FREQ_ERR_MSG, FreqGroup, _period_code_map, get_freq, get_freq_code)
  import pandas.compat as compat
  from pandas.compat import is_platform_windows, range
  
  from pandas import (
      DatetimeIndex, Index, Series, Timedelta, Timestamp, date_range,
      period_range)
  from pandas.core.tools.datetimes import to_datetime
  import pandas.util.testing as tm
  
  import pandas.tseries.frequencies as frequencies
  import pandas.tseries.offsets as offsets
  
  
  class TestToOffset(object):
  
      def test_to_offset_multiple(self):
          freqstr = '2h30min'
          freqstr2 = '2h 30min'
  
          result = frequencies.to_offset(freqstr)
          assert (result == frequencies.to_offset(freqstr2))
          expected = offsets.Minute(150)
          assert (result == expected)
  
          freqstr = '2h30min15s'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Second(150 * 60 + 15)
          assert (result == expected)
  
          freqstr = '2h 60min'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Hour(3)
          assert (result == expected)
  
          freqstr = '2h 20.5min'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Second(8430)
          assert (result == expected)
  
          freqstr = '1.5min'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Second(90)
          assert (result == expected)
  
          freqstr = '0.5S'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Milli(500)
          assert (result == expected)
  
          freqstr = '15l500u'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Micro(15500)
          assert (result == expected)
  
          freqstr = '10s75L'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Milli(10075)
          assert (result == expected)
  
          freqstr = '1s0.25ms'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Micro(1000250)
          assert (result == expected)
  
          freqstr = '1s0.25L'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Micro(1000250)
          assert (result == expected)
  
          freqstr = '2800N'
          result = frequencies.to_offset(freqstr)
          expected = offsets.Nano(2800)
          assert (result == expected)
  
          freqstr = '2SM'
          result = frequencies.to_offset(freqstr)
          expected = offsets.SemiMonthEnd(2)
          assert (result == expected)
  
          freqstr = '2SM-16'
          result = frequencies.to_offset(freqstr)
          expected = offsets.SemiMonthEnd(2, day_of_month=16)
          assert (result == expected)
  
          freqstr = '2SMS-14'
          result = frequencies.to_offset(freqstr)
          expected = offsets.SemiMonthBegin(2, day_of_month=14)
          assert (result == expected)
  
          freqstr = '2SMS-15'
          result = frequencies.to_offset(freqstr)
          expected = offsets.SemiMonthBegin(2)
          assert (result == expected)
  
          # malformed
          with pytest.raises(ValueError, match='Invalid frequency: 2h20m'):
              frequencies.to_offset('2h20m')
  
      def test_to_offset_negative(self):
          freqstr = '-1S'
          result = frequencies.to_offset(freqstr)
          assert (result.n == -1)
  
          freqstr = '-5min10s'
          result = frequencies.to_offset(freqstr)
          assert (result.n == -310)
  
          freqstr = '-2SM'
          result = frequencies.to_offset(freqstr)
          assert (result.n == -2)
  
          freqstr = '-1SMS'
          result = frequencies.to_offset(freqstr)
          assert (result.n == -1)
  
      def test_to_offset_invalid(self):
          # GH 13930
          with pytest.raises(ValueError, match='Invalid frequency: U1'):
              frequencies.to_offset('U1')
          with pytest.raises(ValueError, match='Invalid frequency: -U'):
              frequencies.to_offset('-U')
          with pytest.raises(ValueError, match='Invalid frequency: 3U1'):
              frequencies.to_offset('3U1')
          with pytest.raises(ValueError, match='Invalid frequency: -2-3U'):
              frequencies.to_offset('-2-3U')
          with pytest.raises(ValueError, match='Invalid frequency: -2D:3H'):
              frequencies.to_offset('-2D:3H')
          with pytest.raises(ValueError, match='Invalid frequency: 1.5.0S'):
              frequencies.to_offset('1.5.0S')
  
          # split offsets with spaces are valid
          assert frequencies.to_offset('2D 3H') == offsets.Hour(51)
          assert frequencies.to_offset('2 D3 H') == offsets.Hour(51)
          assert frequencies.to_offset('2 D 3 H') == offsets.Hour(51)
          assert frequencies.to_offset('  2 D 3 H  ') == offsets.Hour(51)
          assert frequencies.to_offset('   H    ') == offsets.Hour()
          assert frequencies.to_offset(' 3  H    ') == offsets.Hour(3)
  
          # special cases
          assert frequencies.to_offset('2SMS-15') == offsets.SemiMonthBegin(2)
          with pytest.raises(ValueError, match='Invalid frequency: 2SMS-15-15'):
              frequencies.to_offset('2SMS-15-15')
          with pytest.raises(ValueError, match='Invalid frequency: 2SMS-15D'):
              frequencies.to_offset('2SMS-15D')
  
      def test_to_offset_leading_zero(self):
          freqstr = '00H 00T 01S'
          result = frequencies.to_offset(freqstr)
          assert (result.n == 1)
  
          freqstr = '-00H 03T 14S'
          result = frequencies.to_offset(freqstr)
          assert (result.n == -194)
  
      def test_to_offset_leading_plus(self):
          freqstr = '+1d'
          result = frequencies.to_offset(freqstr)
          assert (result.n == 1)
  
          freqstr = '+2h30min'
          result = frequencies.to_offset(freqstr)
          assert (result.n == 150)
  
          for bad_freq in ['+-1d', '-+1h', '+1', '-7', '+d', '-m']:
              with pytest.raises(ValueError, match='Invalid frequency:'):
                  frequencies.to_offset(bad_freq)
  
      def test_to_offset_pd_timedelta(self):
          # Tests for #9064
          td = Timedelta(days=1, seconds=1)
          result = frequencies.to_offset(td)
          expected = offsets.Second(86401)
          assert (expected == result)
  
          td = Timedelta(days=-1, seconds=1)
          result = frequencies.to_offset(td)
          expected = offsets.Second(-86399)
          assert (expected == result)
  
          td = Timedelta(hours=1, minutes=10)
          result = frequencies.to_offset(td)
          expected = offsets.Minute(70)
          assert (expected == result)
  
          td = Timedelta(hours=1, minutes=-10)
          result = frequencies.to_offset(td)
          expected = offsets.Minute(50)
          assert (expected == result)
  
          td = Timedelta(weeks=1)
          result = frequencies.to_offset(td)
          expected = offsets.Day(7)
          assert (expected == result)
  
          td1 = Timedelta(hours=1)
          result1 = frequencies.to_offset(td1)
          result2 = frequencies.to_offset('60min')
          assert (result1 == result2)
  
          td = Timedelta(microseconds=1)
          result = frequencies.to_offset(td)
          expected = offsets.Micro(1)
          assert (expected == result)
  
          td = Timedelta(microseconds=0)
          pytest.raises(ValueError, lambda: frequencies.to_offset(td))
  
      def test_anchored_shortcuts(self):
          result = frequencies.to_offset('W')
          expected = frequencies.to_offset('W-SUN')
          assert (result == expected)
  
          result1 = frequencies.to_offset('Q')
          result2 = frequencies.to_offset('Q-DEC')
          expected = offsets.QuarterEnd(startingMonth=12)
          assert (result1 == expected)
          assert (result2 == expected)
  
          result1 = frequencies.to_offset('Q-MAY')
          expected = offsets.QuarterEnd(startingMonth=5)
          assert (result1 == expected)
  
          result1 = frequencies.to_offset('SM')
          result2 = frequencies.to_offset('SM-15')
          expected = offsets.SemiMonthEnd(day_of_month=15)
          assert (result1 == expected)
          assert (result2 == expected)
  
          result = frequencies.to_offset('SM-1')
          expected = offsets.SemiMonthEnd(day_of_month=1)
          assert (result == expected)
  
          result = frequencies.to_offset('SM-27')
          expected = offsets.SemiMonthEnd(day_of_month=27)
          assert (result == expected)
  
          result = frequencies.to_offset('SMS-2')
          expected = offsets.SemiMonthBegin(day_of_month=2)
          assert (result == expected)
  
          result = frequencies.to_offset('SMS-27')
          expected = offsets.SemiMonthBegin(day_of_month=27)
          assert (result == expected)
  
          # ensure invalid cases fail as expected
          invalid_anchors = ['SM-0', 'SM-28', 'SM-29',
                             'SM-FOO', 'BSM', 'SM--1',
                             'SMS-1', 'SMS-28', 'SMS-30',
                             'SMS-BAR', 'SMS-BYR' 'BSMS',
                             'SMS--2']
          for invalid_anchor in invalid_anchors:
              with pytest.raises(ValueError, match='Invalid frequency: '):
                  frequencies.to_offset(invalid_anchor)
  
  
  def test_ms_vs_MS():
      left = frequencies.get_offset('ms')
      right = frequencies.get_offset('MS')
      assert left == offsets.Milli()
      assert right == offsets.MonthBegin()
  
  
  def test_rule_aliases():
      rule = frequencies.to_offset('10us')
      assert rule == offsets.Micro(10)
  
  
  class TestFrequencyCode(object):
  
      def test_freq_code(self):
          assert get_freq('A') == 1000
          assert get_freq('3A') == 1000
          assert get_freq('-1A') == 1000
  
          assert get_freq('Y') == 1000
          assert get_freq('3Y') == 1000
          assert get_freq('-1Y') == 1000
  
          assert get_freq('W') == 4000
          assert get_freq('W-MON') == 4001
          assert get_freq('W-FRI') == 4005
  
          for freqstr, code in compat.iteritems(_period_code_map):
              result = get_freq(freqstr)
              assert result == code
  
              result = resolution.get_freq_group(freqstr)
              assert result == code // 1000 * 1000
  
              result = resolution.get_freq_group(code)
              assert result == code // 1000 * 1000
  
      def test_freq_group(self):
          assert resolution.get_freq_group('A') == 1000
          assert resolution.get_freq_group('3A') == 1000
          assert resolution.get_freq_group('-1A') == 1000
          assert resolution.get_freq_group('A-JAN') == 1000
          assert resolution.get_freq_group('A-MAY') == 1000
  
          assert resolution.get_freq_group('Y') == 1000
          assert resolution.get_freq_group('3Y') == 1000
          assert resolution.get_freq_group('-1Y') == 1000
          assert resolution.get_freq_group('Y-JAN') == 1000
          assert resolution.get_freq_group('Y-MAY') == 1000
  
          assert resolution.get_freq_group(offsets.YearEnd()) == 1000
          assert resolution.get_freq_group(offsets.YearEnd(month=1)) == 1000
          assert resolution.get_freq_group(offsets.YearEnd(month=5)) == 1000
  
          assert resolution.get_freq_group('W') == 4000
          assert resolution.get_freq_group('W-MON') == 4000
          assert resolution.get_freq_group('W-FRI') == 4000
          assert resolution.get_freq_group(offsets.Week()) == 4000
          assert resolution.get_freq_group(offsets.Week(weekday=1)) == 4000
          assert resolution.get_freq_group(offsets.Week(weekday=5)) == 4000
  
      def test_get_to_timestamp_base(self):
          tsb = libfrequencies.get_to_timestamp_base
  
          assert (tsb(get_freq_code('D')[0]) ==
                  get_freq_code('D')[0])
          assert (tsb(get_freq_code('W')[0]) ==
                  get_freq_code('D')[0])
          assert (tsb(get_freq_code('M')[0]) ==
                  get_freq_code('D')[0])
  
          assert (tsb(get_freq_code('S')[0]) ==
                  get_freq_code('S')[0])
          assert (tsb(get_freq_code('T')[0]) ==
                  get_freq_code('S')[0])
          assert (tsb(get_freq_code('H')[0]) ==
                  get_freq_code('S')[0])
  
      def test_freq_to_reso(self):
          Reso = resolution.Resolution
  
          assert Reso.get_str_from_freq('A') == 'year'
          assert Reso.get_str_from_freq('Q') == 'quarter'
          assert Reso.get_str_from_freq('M') == 'month'
          assert Reso.get_str_from_freq('D') == 'day'
          assert Reso.get_str_from_freq('H') == 'hour'
          assert Reso.get_str_from_freq('T') == 'minute'
          assert Reso.get_str_from_freq('S') == 'second'
          assert Reso.get_str_from_freq('L') == 'millisecond'
          assert Reso.get_str_from_freq('U') == 'microsecond'
          assert Reso.get_str_from_freq('N') == 'nanosecond'
  
          for freq in ['A', 'Q', 'M', 'D', 'H', 'T', 'S', 'L', 'U', 'N']:
              # check roundtrip
              result = Reso.get_freq(Reso.get_str_from_freq(freq))
              assert freq == result
  
          for freq in ['D', 'H', 'T', 'S', 'L', 'U']:
              result = Reso.get_freq(Reso.get_str(Reso.get_reso_from_freq(freq)))
              assert freq == result
  
      def test_resolution_bumping(self):
          # see gh-14378
          Reso = resolution.Resolution
  
          assert Reso.get_stride_from_decimal(1.5, 'T') == (90, 'S')
          assert Reso.get_stride_from_decimal(62.4, 'T') == (3744, 'S')
          assert Reso.get_stride_from_decimal(1.04, 'H') == (3744, 'S')
          assert Reso.get_stride_from_decimal(1, 'D') == (1, 'D')
          assert (Reso.get_stride_from_decimal(0.342931, 'H') ==
                  (1234551600, 'U'))
          assert Reso.get_stride_from_decimal(1.2345, 'D') == (106660800, 'L')
  
          with pytest.raises(ValueError):
              Reso.get_stride_from_decimal(0.5, 'N')
  
          # too much precision in the input can prevent
          with pytest.raises(ValueError):
              Reso.get_stride_from_decimal(0.3429324798798269273987982, 'H')
  
      def test_get_freq_code(self):
          # frequency str
          assert (get_freq_code('A') ==
                  (get_freq('A'), 1))
          assert (get_freq_code('3D') ==
                  (get_freq('D'), 3))
          assert (get_freq_code('-2M') ==
                  (get_freq('M'), -2))
  
          # tuple
          assert (get_freq_code(('D', 1)) ==
                  (get_freq('D'), 1))
          assert (get_freq_code(('A', 3)) ==
                  (get_freq('A'), 3))
          assert (get_freq_code(('M', -2)) ==
                  (get_freq('M'), -2))
  
          # numeric tuple
          assert get_freq_code((1000, 1)) == (1000, 1)
  
          # offsets
          assert (get_freq_code(offsets.Day()) ==
                  (get_freq('D'), 1))
          assert (get_freq_code(offsets.Day(3)) ==
                  (get_freq('D'), 3))
          assert (get_freq_code(offsets.Day(-2)) ==
                  (get_freq('D'), -2))
  
          assert (get_freq_code(offsets.MonthEnd()) ==
                  (get_freq('M'), 1))
          assert (get_freq_code(offsets.MonthEnd(3)) ==
                  (get_freq('M'), 3))
          assert (get_freq_code(offsets.MonthEnd(-2)) ==
                  (get_freq('M'), -2))
  
          assert (get_freq_code(offsets.Week()) ==
                  (get_freq('W'), 1))
          assert (get_freq_code(offsets.Week(3)) ==
                  (get_freq('W'), 3))
          assert (get_freq_code(offsets.Week(-2)) ==
                  (get_freq('W'), -2))
  
          # Monday is weekday=0
          assert (get_freq_code(offsets.Week(weekday=1)) ==
                  (get_freq('W-TUE'), 1))
          assert (get_freq_code(offsets.Week(3, weekday=0)) ==
                  (get_freq('W-MON'), 3))
          assert (get_freq_code(offsets.Week(-2, weekday=4)) ==
                  (get_freq('W-FRI'), -2))
  
      def test_frequency_misc(self):
          assert (resolution.get_freq_group('T') ==
                  FreqGroup.FR_MIN)
  
          code, stride = get_freq_code(offsets.Hour())
          assert code == FreqGroup.FR_HR
  
          code, stride = get_freq_code((5, 'T'))
          assert code == FreqGroup.FR_MIN
          assert stride == 5
  
          offset = offsets.Hour()
          result = frequencies.to_offset(offset)
          assert result == offset
  
          result = frequencies.to_offset((5, 'T'))
          expected = offsets.Minute(5)
          assert result == expected
  
          with pytest.raises(ValueError, match='Invalid frequency'):
              get_freq_code((5, 'baz'))
  
          with pytest.raises(ValueError, match='Invalid frequency'):
              frequencies.to_offset('100foo')
  
          with pytest.raises(ValueError, match='Could not evaluate'):
              frequencies.to_offset(('', ''))
  
  
  _dti = DatetimeIndex
  
  
  class TestFrequencyInference(object):
  
      def test_raise_if_period_index(self):
          index = period_range(start="1/1/1990", periods=20, freq="M")
          pytest.raises(TypeError, frequencies.infer_freq, index)
  
      def test_raise_if_too_few(self):
          index = _dti(['12/31/1998', '1/3/1999'])
          pytest.raises(ValueError, frequencies.infer_freq, index)
  
      def test_business_daily(self):
          index = _dti(['01/01/1999', '1/4/1999', '1/5/1999'])
          assert frequencies.infer_freq(index) == 'B'
  
      def test_business_daily_look_alike(self):
          # GH 16624, do not infer 'B' when 'weekend' (2-day gap) in wrong place
          index = _dti(['12/31/1998', '1/3/1999', '1/4/1999'])
          assert frequencies.infer_freq(index) is None
  
      def test_day(self):
          self._check_tick(timedelta(1), 'D')
  
      def test_day_corner(self):
          index = _dti(['1/1/2000', '1/2/2000', '1/3/2000'])
          assert frequencies.infer_freq(index) == 'D'
  
      def test_non_datetimeindex(self):
          dates = to_datetime(['1/1/2000', '1/2/2000', '1/3/2000'])
          assert frequencies.infer_freq(dates) == 'D'
  
      def test_hour(self):
          self._check_tick(timedelta(hours=1), 'H')
  
      def test_minute(self):
          self._check_tick(timedelta(minutes=1), 'T')
  
      def test_second(self):
          self._check_tick(timedelta(seconds=1), 'S')
  
      def test_millisecond(self):
          self._check_tick(timedelta(microseconds=1000), 'L')
  
      def test_microsecond(self):
          self._check_tick(timedelta(microseconds=1), 'U')
  
      def test_nanosecond(self):
          self._check_tick(np.timedelta64(1, 'ns'), 'N')
  
      def _check_tick(self, base_delta, code):
          b = Timestamp(datetime.now())
          for i in range(1, 5):
              inc = base_delta * i
              index = _dti([b + inc * j for j in range(3)])
              if i > 1:
                  exp_freq = '%d%s' % (i, code)
              else:
                  exp_freq = code
              assert frequencies.infer_freq(index) == exp_freq
  
          index = _dti([b + base_delta * 7] + [b + base_delta * j for j in range(
              3)])
          assert frequencies.infer_freq(index) is None
  
          index = _dti([b + base_delta * j for j in range(3)] + [b + base_delta *
                                                                 7])
  
          assert frequencies.infer_freq(index) is None
  
      def test_weekly(self):
          days = ['MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT', 'SUN']
  
          for day in days:
              self._check_generated_range('1/1/2000', 'W-%s' % day)
  
      def test_week_of_month(self):
          days = ['MON', 'TUE', 'WED', 'THU', 'FRI', 'SAT', 'SUN']
  
          for day in days:
              for i in range(1, 5):
                  self._check_generated_range('1/1/2000', 'WOM-%d%s' % (i, day))
  
      def test_fifth_week_of_month(self):
          # Only supports freq up to WOM-4. See #9425
          func = lambda: date_range('2014-01-01', freq='WOM-5MON')
          pytest.raises(ValueError, func)
  
      def test_fifth_week_of_month_infer(self):
          # Only attempts to infer up to WOM-4. See #9425
          index = DatetimeIndex(["2014-03-31", "2014-06-30", "2015-03-30"])
          assert frequencies.infer_freq(index) is None
  
      def test_week_of_month_fake(self):
          # All of these dates are on same day of week and are 4 or 5 weeks apart
          index = DatetimeIndex(["2013-08-27", "2013-10-01", "2013-10-29",
                                 "2013-11-26"])
          assert frequencies.infer_freq(index) != 'WOM-4TUE'
  
      def test_monthly(self):
          self._check_generated_range('1/1/2000', 'M')
  
      def test_monthly_ambiguous(self):
          rng = _dti(['1/31/2000', '2/29/2000', '3/31/2000'])
          assert rng.inferred_freq == 'M'
  
      def test_business_monthly(self):
          self._check_generated_range('1/1/2000', 'BM')
  
      def test_business_start_monthly(self):
          self._check_generated_range('1/1/2000', 'BMS')
  
      def test_quarterly(self):
          for month in ['JAN', 'FEB', 'MAR']:
              self._check_generated_range('1/1/2000', 'Q-%s' % month)
  
      def test_annual(self):
          for month in MONTHS:
              self._check_generated_range('1/1/2000', 'A-%s' % month)
  
      def test_business_annual(self):
          for month in MONTHS:
              self._check_generated_range('1/1/2000', 'BA-%s' % month)
  
      def test_annual_ambiguous(self):
          rng = _dti(['1/31/2000', '1/31/2001', '1/31/2002'])
          assert rng.inferred_freq == 'A-JAN'
  
      def _check_generated_range(self, start, freq):
          freq = freq.upper()
  
          gen = date_range(start, periods=7, freq=freq)
          index = _dti(gen.values)
          if not freq.startswith('Q-'):
              assert frequencies.infer_freq(index) == gen.freqstr
          else:
              inf_freq = frequencies.infer_freq(index)
              is_dec_range = inf_freq == 'Q-DEC' and gen.freqstr in (
                  'Q', 'Q-DEC', 'Q-SEP', 'Q-JUN', 'Q-MAR')
              is_nov_range = inf_freq == 'Q-NOV' and gen.freqstr in (
                  'Q-NOV', 'Q-AUG', 'Q-MAY', 'Q-FEB')
              is_oct_range = inf_freq == 'Q-OCT' and gen.freqstr in (
                  'Q-OCT', 'Q-JUL', 'Q-APR', 'Q-JAN')
              assert is_dec_range or is_nov_range or is_oct_range
  
          gen = date_range(start, periods=5, freq=freq)
          index = _dti(gen.values)
  
          if not freq.startswith('Q-'):
              assert frequencies.infer_freq(index) == gen.freqstr
          else:
              inf_freq = frequencies.infer_freq(index)
              is_dec_range = inf_freq == 'Q-DEC' and gen.freqstr in (
                  'Q', 'Q-DEC', 'Q-SEP', 'Q-JUN', 'Q-MAR')
              is_nov_range = inf_freq == 'Q-NOV' and gen.freqstr in (
                  'Q-NOV', 'Q-AUG', 'Q-MAY', 'Q-FEB')
              is_oct_range = inf_freq == 'Q-OCT' and gen.freqstr in (
                  'Q-OCT', 'Q-JUL', 'Q-APR', 'Q-JAN')
  
              assert is_dec_range or is_nov_range or is_oct_range
  
      def test_infer_freq(self):
          rng = period_range('1959Q2', '2009Q3', freq='Q')
          rng = Index(rng.to_timestamp('D', how='e').astype(object))
          assert rng.inferred_freq == 'Q-DEC'
  
          rng = period_range('1959Q2', '2009Q3', freq='Q-NOV')
          rng = Index(rng.to_timestamp('D', how='e').astype(object))
          assert rng.inferred_freq == 'Q-NOV'
  
          rng = period_range('1959Q2', '2009Q3', freq='Q-OCT')
          rng = Index(rng.to_timestamp('D', how='e').astype(object))
          assert rng.inferred_freq == 'Q-OCT'
  
      def test_infer_freq_tz(self):
  
          freqs = {'AS-JAN':
                   ['2009-01-01', '2010-01-01', '2011-01-01', '2012-01-01'],
                   'Q-OCT':
                   ['2009-01-31', '2009-04-30', '2009-07-31', '2009-10-31'],
                   'M': ['2010-11-30', '2010-12-31', '2011-01-31', '2011-02-28'],
                   'W-SAT':
                   ['2010-12-25', '2011-01-01', '2011-01-08', '2011-01-15'],
                   'D': ['2011-01-01', '2011-01-02', '2011-01-03', '2011-01-04'],
                   'H': ['2011-12-31 22:00', '2011-12-31 23:00',
                         '2012-01-01 00:00', '2012-01-01 01:00']}
  
          # GH 7310
          for tz in [None, 'Australia/Sydney', 'Asia/Tokyo', 'Europe/Paris',
                     'US/Pacific', 'US/Eastern']:
              for expected, dates in compat.iteritems(freqs):
                  idx = DatetimeIndex(dates, tz=tz)
                  assert idx.inferred_freq == expected
  
      def test_infer_freq_tz_transition(self):
          # Tests for #8772
          date_pairs = [['2013-11-02', '2013-11-5'],  # Fall DST
                        ['2014-03-08', '2014-03-11'],  # Spring DST
                        ['2014-01-01', '2014-01-03']]  # Regular Time
          freqs = ['3H', '10T', '3601S', '3600001L', '3600000001U',
                   '3600000000001N']
  
          for tz in [None, 'Australia/Sydney', 'Asia/Tokyo', 'Europe/Paris',
                     'US/Pacific', 'US/Eastern']:
              for date_pair in date_pairs:
                  for freq in freqs:
                      idx = date_range(date_pair[0], date_pair[
                          1], freq=freq, tz=tz)
                      assert idx.inferred_freq == freq
  
          index = date_range("2013-11-03", periods=5,
                             freq="3H").tz_localize("America/Chicago")
          assert index.inferred_freq is None
  
      def test_infer_freq_businesshour(self):
          # GH 7905
          idx = DatetimeIndex(
              ['2014-07-01 09:00', '2014-07-01 10:00', '2014-07-01 11:00',
               '2014-07-01 12:00', '2014-07-01 13:00', '2014-07-01 14:00'])
          # hourly freq in a day must result in 'H'
          assert idx.inferred_freq == 'H'
  
          idx = DatetimeIndex(
              ['2014-07-01 09:00', '2014-07-01 10:00', '2014-07-01 11:00',
               '2014-07-01 12:00', '2014-07-01 13:00', '2014-07-01 14:00',
               '2014-07-01 15:00', '2014-07-01 16:00', '2014-07-02 09:00',
               '2014-07-02 10:00', '2014-07-02 11:00'])
          assert idx.inferred_freq == 'BH'
  
          idx = DatetimeIndex(
              ['2014-07-04 09:00', '2014-07-04 10:00', '2014-07-04 11:00',
               '2014-07-04 12:00', '2014-07-04 13:00', '2014-07-04 14:00',
               '2014-07-04 15:00', '2014-07-04 16:00', '2014-07-07 09:00',
               '2014-07-07 10:00', '2014-07-07 11:00'])
          assert idx.inferred_freq == 'BH'
  
          idx = DatetimeIndex(
              ['2014-07-04 09:00', '2014-07-04 10:00', '2014-07-04 11:00',
               '2014-07-04 12:00', '2014-07-04 13:00', '2014-07-04 14:00',
               '2014-07-04 15:00', '2014-07-04 16:00', '2014-07-07 09:00',
               '2014-07-07 10:00', '2014-07-07 11:00', '2014-07-07 12:00',
               '2014-07-07 13:00', '2014-07-07 14:00', '2014-07-07 15:00',
               '2014-07-07 16:00', '2014-07-08 09:00', '2014-07-08 10:00',
               '2014-07-08 11:00', '2014-07-08 12:00', '2014-07-08 13:00',
               '2014-07-08 14:00', '2014-07-08 15:00', '2014-07-08 16:00'])
          assert idx.inferred_freq == 'BH'
  
      def test_not_monotonic(self):
          rng = _dti(['1/31/2000', '1/31/2001', '1/31/2002'])
          rng = rng[::-1]
          assert rng.inferred_freq == '-1A-JAN'
  
      def test_non_datetimeindex2(self):
          rng = _dti(['1/31/2000', '1/31/2001', '1/31/2002'])
  
          vals = rng.to_pydatetime()
  
          result = frequencies.infer_freq(vals)
          assert result == rng.inferred_freq
  
      def test_invalid_index_types(self):
  
          # test all index types
          for i in [tm.makeIntIndex(10), tm.makeFloatIndex(10),
                    tm.makePeriodIndex(10)]:
              pytest.raises(TypeError, lambda: frequencies.infer_freq(i))
  
          # GH 10822
          # odd error message on conversions to datetime for unicode
          if not is_platform_windows():
              for i in [tm.makeStringIndex(10), tm.makeUnicodeIndex(10)]:
                  pytest.raises(ValueError, lambda: frequencies.infer_freq(i))
  
      def test_string_datetimelike_compat(self):
  
          # GH 6463
          expected = frequencies.infer_freq(['2004-01', '2004-02', '2004-03',
                                             '2004-04'])
          result = frequencies.infer_freq(Index(['2004-01', '2004-02', '2004-03',
                                                 '2004-04']))
          assert result == expected
  
      def test_series(self):
  
          # GH6407
          # inferring series
  
          # invalid type of Series
          for s in [Series(np.arange(10)), Series(np.arange(10.))]:
              pytest.raises(TypeError, lambda: frequencies.infer_freq(s))
  
          # a non-convertible string
          pytest.raises(ValueError, lambda: frequencies.infer_freq(
              Series(['foo', 'bar'])))
  
          # cannot infer on PeriodIndex
          for freq in [None, 'L']:
              s = Series(period_range('2013', periods=10, freq=freq))
              pytest.raises(TypeError, lambda: frequencies.infer_freq(s))
  
          # DateTimeIndex
          for freq in ['M', 'L', 'S']:
              s = Series(date_range('20130101', periods=10, freq=freq))
              inferred = frequencies.infer_freq(s)
              assert inferred == freq
  
          s = Series(date_range('20130101', '20130110'))
          inferred = frequencies.infer_freq(s)
          assert inferred == 'D'
  
      def test_legacy_offset_warnings(self):
          freqs = ['WEEKDAY', 'EOM', 'W@MON', 'W@TUE', 'W@WED', 'W@THU',
                   'W@FRI', 'W@SAT', 'W@SUN', 'Q@JAN', 'Q@FEB', 'Q@MAR',
                   'A@JAN', 'A@FEB', 'A@MAR', 'A@APR', 'A@MAY', 'A@JUN',
                   'A@JUL', 'A@AUG', 'A@SEP', 'A@OCT', 'A@NOV', 'A@DEC',
                   'Y@JAN', 'WOM@1MON', 'WOM@2MON', 'WOM@3MON',
                   'WOM@4MON', 'WOM@1TUE', 'WOM@2TUE', 'WOM@3TUE',
                   'WOM@4TUE', 'WOM@1WED', 'WOM@2WED', 'WOM@3WED',
                   'WOM@4WED', 'WOM@1THU', 'WOM@2THU', 'WOM@3THU',
                   'WOM@4THU', 'WOM@1FRI', 'WOM@2FRI', 'WOM@3FRI',
                   'WOM@4FRI']
  
          msg = INVALID_FREQ_ERR_MSG
          for freq in freqs:
              with pytest.raises(ValueError, match=msg):
                  frequencies.get_offset(freq)
  
              with pytest.raises(ValueError, match=msg):
                  date_range('2011-01-01', periods=5, freq=freq)
  