manyi/venv/Lib/site-packages/pandas/tests/scalar/period/test_period.py

from datetime import date, datetime, timedelta

import numpy as np
import pytest
import pytz

from pandas._libs.tslibs import iNaT, period as libperiod
from pandas._libs.tslibs.ccalendar import DAYS, MONTHS
from pandas._libs.tslibs.frequencies import INVALID_FREQ_ERR_MSG
from pandas._libs.tslibs.parsing import DateParseError
from pandas._libs.tslibs.timezones import dateutil_gettz, maybe_get_tz
from pandas.compat import iteritems, text_type
from pandas.compat.numpy import np_datetime64_compat

import pandas as pd
from pandas import NaT, Period, Timedelta, Timestamp, offsets
import pandas.core.indexes.period as period
import pandas.util.testing as tm


class TestPeriodConstruction(object):
    def test_construction(self):
        i1 = Period('1/1/2005', freq='M')
        i2 = Period('Jan 2005')

        assert i1 == i2

        i1 = Period('2005', freq='A')
        i2 = Period('2005')
        i3 = Period('2005', freq='a')

        assert i1 == i2
        assert i1 == i3

        i4 = Period('2005', freq='M')
        i5 = Period('2005', freq='m')

        pytest.raises(ValueError, i1.__ne__, i4)
        assert i4 == i5

        i1 = Period.now('Q')
        i2 = Period(datetime.now(), freq='Q')
        i3 = Period.now('q')

        assert i1 == i2
        assert i1 == i3

        i1 = Period('1982', freq='min')
        i2 = Period('1982', freq='MIN')
        assert i1 == i2
        i2 = Period('1982', freq=('Min', 1))
        assert i1 == i2

        i1 = Period(year=2005, month=3, day=1, freq='D')
        i2 = Period('3/1/2005', freq='D')
        assert i1 == i2

        i3 = Period(year=2005, month=3, day=1, freq='d')
        assert i1 == i3

        i1 = Period('2007-01-01 09:00:00.001')
        expected = Period(datetime(2007, 1, 1, 9, 0, 0, 1000), freq='L')
        assert i1 == expected

        expected = Period(np_datetime64_compat(
            '2007-01-01 09:00:00.001Z'), freq='L')
        assert i1 == expected

        i1 = Period('2007-01-01 09:00:00.00101')
        expected = Period(datetime(2007, 1, 1, 9, 0, 0, 1010), freq='U')
        assert i1 == expected

        expected = Period(np_datetime64_compat('2007-01-01 09:00:00.00101Z'),
                          freq='U')
        assert i1 == expected

        pytest.raises(ValueError, Period, ordinal=200701)

        pytest.raises(ValueError, Period, '2007-1-1', freq='X')

    def test_construction_bday(self):

        # Biz day construction, roll forward if non-weekday
        i1 = Period('3/10/12', freq='B')
        i2 = Period('3/10/12', freq='D')
        assert i1 == i2.asfreq('B')
        i2 = Period('3/11/12', freq='D')
        assert i1 == i2.asfreq('B')
        i2 = Period('3/12/12', freq='D')
        assert i1 == i2.asfreq('B')

        i3 = Period('3/10/12', freq='b')
        assert i1 == i3

        i1 = Period(year=2012, month=3, day=10, freq='B')
        i2 = Period('3/12/12', freq='B')
        assert i1 == i2

    def test_construction_quarter(self):

        i1 = Period(year=2005, quarter=1, freq='Q')
        i2 = Period('1/1/2005', freq='Q')
        assert i1 == i2

        i1 = Period(year=2005, quarter=3, freq='Q')
        i2 = Period('9/1/2005', freq='Q')
        assert i1 == i2

        i1 = Period('2005Q1')
        i2 = Period(year=2005, quarter=1, freq='Q')
        i3 = Period('2005q1')
        assert i1 == i2
        assert i1 == i3

        i1 = Period('05Q1')
        assert i1 == i2
        lower = Period('05q1')
        assert i1 == lower

        i1 = Period('1Q2005')
        assert i1 == i2
        lower = Period('1q2005')
        assert i1 == lower

        i1 = Period('1Q05')
        assert i1 == i2
        lower = Period('1q05')
        assert i1 == lower

        i1 = Period('4Q1984')
        assert i1.year == 1984
        lower = Period('4q1984')
        assert i1 == lower

    def test_construction_month(self):

        expected = Period('2007-01', freq='M')
        i1 = Period('200701', freq='M')
        assert i1 == expected

        i1 = Period('200701', freq='M')
        assert i1 == expected

        i1 = Period(200701, freq='M')
        assert i1 == expected

        i1 = Period(ordinal=200701, freq='M')
        assert i1.year == 18695

        i1 = Period(datetime(2007, 1, 1), freq='M')
        i2 = Period('200701', freq='M')
        assert i1 == i2

        i1 = Period(date(2007, 1, 1), freq='M')
        i2 = Period(datetime(2007, 1, 1), freq='M')
        i3 = Period(np.datetime64('2007-01-01'), freq='M')
        i4 = Period(np_datetime64_compat('2007-01-01 00:00:00Z'), freq='M')
        i5 = Period(np_datetime64_compat('2007-01-01 00:00:00.000Z'), freq='M')
        assert i1 == i2
        assert i1 == i3
        assert i1 == i4
        assert i1 == i5

    def test_period_constructor_offsets(self):
        assert (Period('1/1/2005', freq=offsets.MonthEnd()) ==
                Period('1/1/2005', freq='M'))
        assert (Period('2005', freq=offsets.YearEnd()) ==
                Period('2005', freq='A'))
        assert (Period('2005', freq=offsets.MonthEnd()) ==
                Period('2005', freq='M'))
        assert (Period('3/10/12', freq=offsets.BusinessDay()) ==
                Period('3/10/12', freq='B'))
        assert (Period('3/10/12', freq=offsets.Day()) ==
                Period('3/10/12', freq='D'))

        assert (Period(year=2005, quarter=1,
                       freq=offsets.QuarterEnd(startingMonth=12)) ==
                Period(year=2005, quarter=1, freq='Q'))
        assert (Period(year=2005, quarter=2,
                       freq=offsets.QuarterEnd(startingMonth=12)) ==
                Period(year=2005, quarter=2, freq='Q'))

        assert (Period(year=2005, month=3, day=1, freq=offsets.Day()) ==
                Period(year=2005, month=3, day=1, freq='D'))
        assert (Period(year=2012, month=3, day=10, freq=offsets.BDay()) ==
                Period(year=2012, month=3, day=10, freq='B'))

        expected = Period('2005-03-01', freq='3D')
        assert (Period(year=2005, month=3, day=1,
                       freq=offsets.Day(3)) == expected)
        assert Period(year=2005, month=3, day=1, freq='3D') == expected

        assert (Period(year=2012, month=3, day=10,
                       freq=offsets.BDay(3)) ==
                Period(year=2012, month=3, day=10, freq='3B'))

        assert (Period(200701, freq=offsets.MonthEnd()) ==
                Period(200701, freq='M'))

        i1 = Period(ordinal=200701, freq=offsets.MonthEnd())
        i2 = Period(ordinal=200701, freq='M')
        assert i1 == i2
        assert i1.year == 18695
        assert i2.year == 18695

        i1 = Period(datetime(2007, 1, 1), freq='M')
        i2 = Period('200701', freq='M')
        assert i1 == i2

        i1 = Period(date(2007, 1, 1), freq='M')
        i2 = Period(datetime(2007, 1, 1), freq='M')
        i3 = Period(np.datetime64('2007-01-01'), freq='M')
        i4 = Period(np_datetime64_compat('2007-01-01 00:00:00Z'), freq='M')
        i5 = Period(np_datetime64_compat('2007-01-01 00:00:00.000Z'), freq='M')
        assert i1 == i2
        assert i1 == i3
        assert i1 == i4
        assert i1 == i5

        i1 = Period('2007-01-01 09:00:00.001')
        expected = Period(datetime(2007, 1, 1, 9, 0, 0, 1000), freq='L')
        assert i1 == expected

        expected = Period(np_datetime64_compat(
            '2007-01-01 09:00:00.001Z'), freq='L')
        assert i1 == expected

        i1 = Period('2007-01-01 09:00:00.00101')
        expected = Period(datetime(2007, 1, 1, 9, 0, 0, 1010), freq='U')
        assert i1 == expected

        expected = Period(np_datetime64_compat('2007-01-01 09:00:00.00101Z'),
                          freq='U')
        assert i1 == expected

        pytest.raises(ValueError, Period, ordinal=200701)

        pytest.raises(ValueError, Period, '2007-1-1', freq='X')

    def test_invalid_arguments(self):
        with pytest.raises(ValueError):
            Period(datetime.now())
        with pytest.raises(ValueError):
            Period(datetime.now().date())

        with pytest.raises(ValueError):
            Period(1.6, freq='D')
        with pytest.raises(ValueError):
            Period(ordinal=1.6, freq='D')
        with pytest.raises(ValueError):
            Period(ordinal=2, value=1, freq='D')

        with pytest.raises(ValueError):
            Period(month=1)

        with pytest.raises(ValueError):
            Period('-2000', 'A')
        with pytest.raises(DateParseError):
            Period('0', 'A')
        with pytest.raises(DateParseError):
            Period('1/1/-2000', 'A')

    def test_constructor_corner(self):
        expected = Period('2007-01', freq='2M')
        assert Period(year=2007, month=1, freq='2M') == expected

        assert Period(None) is NaT

        p = Period('2007-01-01', freq='D')

        result = Period(p, freq='A')
        exp = Period('2007', freq='A')
        assert result == exp

    def test_constructor_infer_freq(self):
        p = Period('2007-01-01')
        assert p.freq == 'D'

        p = Period('2007-01-01 07')
        assert p.freq == 'H'

        p = Period('2007-01-01 07:10')
        assert p.freq == 'T'

        p = Period('2007-01-01 07:10:15')
        assert p.freq == 'S'

        p = Period('2007-01-01 07:10:15.123')
        assert p.freq == 'L'

        p = Period('2007-01-01 07:10:15.123000')
        assert p.freq == 'L'

        p = Period('2007-01-01 07:10:15.123400')
        assert p.freq == 'U'

    def test_multiples(self):
        result1 = Period('1989', freq='2A')
        result2 = Period('1989', freq='A')
        assert result1.ordinal == result2.ordinal
        assert result1.freqstr == '2A-DEC'
        assert result2.freqstr == 'A-DEC'
        assert result1.freq == offsets.YearEnd(2)
        assert result2.freq == offsets.YearEnd()

        assert (result1 + 1).ordinal == result1.ordinal + 2
        assert (1 + result1).ordinal == result1.ordinal + 2
        assert (result1 - 1).ordinal == result2.ordinal - 2
        assert (-1 + result1).ordinal == result2.ordinal - 2

    @pytest.mark.parametrize('month', MONTHS)
    def test_period_cons_quarterly(self, month):
        # bugs in scikits.timeseries
        freq = 'Q-%s' % month
        exp = Period('1989Q3', freq=freq)
        assert '1989Q3' in str(exp)
        stamp = exp.to_timestamp('D', how='end')
        p = Period(stamp, freq=freq)
        assert p == exp

        stamp = exp.to_timestamp('3D', how='end')
        p = Period(stamp, freq=freq)
        assert p == exp

    @pytest.mark.parametrize('month', MONTHS)
    def test_period_cons_annual(self, month):
        # bugs in scikits.timeseries
        freq = 'A-%s' % month
        exp = Period('1989', freq=freq)
        stamp = exp.to_timestamp('D', how='end') + timedelta(days=30)
        p = Period(stamp, freq=freq)

        assert p == exp + 1
        assert isinstance(p, Period)

    @pytest.mark.parametrize('day', DAYS)
    @pytest.mark.parametrize('num', range(10, 17))
    def test_period_cons_weekly(self, num, day):
        daystr = '2011-02-%d' % num
        freq = 'W-%s' % day

        result = Period(daystr, freq=freq)
        expected = Period(daystr, freq='D').asfreq(freq)
        assert result == expected
        assert isinstance(result, Period)

    def test_period_from_ordinal(self):
        p = Period('2011-01', freq='M')
        res = Period._from_ordinal(p.ordinal, freq='M')
        assert p == res
        assert isinstance(res, Period)

    def test_period_cons_nat(self):
        p = Period('NaT', freq='M')
        assert p is NaT

        p = Period('nat', freq='W-SUN')
        assert p is NaT

        p = Period(iNaT, freq='D')
        assert p is NaT

        p = Period(iNaT, freq='3D')
        assert p is NaT

        p = Period(iNaT, freq='1D1H')
        assert p is NaT

        p = Period('NaT')
        assert p is NaT

        p = Period(iNaT)
        assert p is NaT

    def test_period_cons_mult(self):
        p1 = Period('2011-01', freq='3M')
        p2 = Period('2011-01', freq='M')
        assert p1.ordinal == p2.ordinal

        assert p1.freq == offsets.MonthEnd(3)
        assert p1.freqstr == '3M'

        assert p2.freq == offsets.MonthEnd()
        assert p2.freqstr == 'M'

        result = p1 + 1
        assert result.ordinal == (p2 + 3).ordinal

        assert result.freq == p1.freq
        assert result.freqstr == '3M'

        result = p1 - 1
        assert result.ordinal == (p2 - 3).ordinal
        assert result.freq == p1.freq
        assert result.freqstr == '3M'

        msg = ('Frequency must be positive, because it'
               ' represents span: -3M')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='-3M')

        msg = ('Frequency must be positive, because it' ' represents span: 0M')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='0M')

    def test_period_cons_combined(self):
        p = [(Period('2011-01', freq='1D1H'),
              Period('2011-01', freq='1H1D'),
              Period('2011-01', freq='H')),
             (Period(ordinal=1, freq='1D1H'),
              Period(ordinal=1, freq='1H1D'),
              Period(ordinal=1, freq='H'))]

        for p1, p2, p3 in p:
            assert p1.ordinal == p3.ordinal
            assert p2.ordinal == p3.ordinal

            assert p1.freq == offsets.Hour(25)
            assert p1.freqstr == '25H'

            assert p2.freq == offsets.Hour(25)
            assert p2.freqstr == '25H'

            assert p3.freq == offsets.Hour()
            assert p3.freqstr == 'H'

            result = p1 + 1
            assert result.ordinal == (p3 + 25).ordinal
            assert result.freq == p1.freq
            assert result.freqstr == '25H'

            result = p2 + 1
            assert result.ordinal == (p3 + 25).ordinal
            assert result.freq == p2.freq
            assert result.freqstr == '25H'

            result = p1 - 1
            assert result.ordinal == (p3 - 25).ordinal
            assert result.freq == p1.freq
            assert result.freqstr == '25H'

            result = p2 - 1
            assert result.ordinal == (p3 - 25).ordinal
            assert result.freq == p2.freq
            assert result.freqstr == '25H'

        msg = ('Frequency must be positive, because it'
               ' represents span: -25H')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='-1D1H')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='-1H1D')
        with pytest.raises(ValueError, match=msg):
            Period(ordinal=1, freq='-1D1H')
        with pytest.raises(ValueError, match=msg):
            Period(ordinal=1, freq='-1H1D')

        msg = ('Frequency must be positive, because it'
               ' represents span: 0D')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='0D0H')
        with pytest.raises(ValueError, match=msg):
            Period(ordinal=1, freq='0D0H')

        # You can only combine together day and intraday offsets
        msg = ('Invalid frequency: 1W1D')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='1W1D')
        msg = ('Invalid frequency: 1D1W')
        with pytest.raises(ValueError, match=msg):
            Period('2011-01', freq='1D1W')


class TestPeriodMethods(object):
    def test_round_trip(self):
        p = Period('2000Q1')
        new_p = tm.round_trip_pickle(p)
        assert new_p == p

    def test_hash(self):
        assert (hash(Period('2011-01', freq='M')) ==
                hash(Period('2011-01', freq='M')))

        assert (hash(Period('2011-01-01', freq='D')) !=
                hash(Period('2011-01', freq='M')))

        assert (hash(Period('2011-01', freq='3M')) !=
                hash(Period('2011-01', freq='2M')))

        assert (hash(Period('2011-01', freq='M')) !=
                hash(Period('2011-02', freq='M')))

    # --------------------------------------------------------------
    # to_timestamp

    @pytest.mark.parametrize('tzstr', ['Europe/Brussels',
                                       'Asia/Tokyo', 'US/Pacific'])
    def test_to_timestamp_tz_arg(self, tzstr):
        p = Period('1/1/2005', freq='M').to_timestamp(tz=tzstr)
        exp = Timestamp('1/1/2005', tz='UTC').tz_convert(tzstr)
        exp_zone = pytz.timezone(tzstr).normalize(p)

        assert p == exp
        assert p.tz == exp_zone.tzinfo
        assert p.tz == exp.tz

        p = Period('1/1/2005', freq='3H').to_timestamp(tz=tzstr)
        exp = Timestamp('1/1/2005', tz='UTC').tz_convert(tzstr)
        exp_zone = pytz.timezone(tzstr).normalize(p)

        assert p == exp
        assert p.tz == exp_zone.tzinfo
        assert p.tz == exp.tz

        p = Period('1/1/2005', freq='A').to_timestamp(freq='A', tz=tzstr)
        exp = Timestamp('31/12/2005', tz='UTC').tz_convert(tzstr)
        exp_zone = pytz.timezone(tzstr).normalize(p)

        assert p == exp
        assert p.tz == exp_zone.tzinfo
        assert p.tz == exp.tz

        p = Period('1/1/2005', freq='A').to_timestamp(freq='3H', tz=tzstr)
        exp = Timestamp('1/1/2005', tz='UTC').tz_convert(tzstr)
        exp_zone = pytz.timezone(tzstr).normalize(p)

        assert p == exp
        assert p.tz == exp_zone.tzinfo
        assert p.tz == exp.tz

    @pytest.mark.parametrize('tzstr', ['dateutil/Europe/Brussels',
                                       'dateutil/Asia/Tokyo',
                                       'dateutil/US/Pacific'])
    def test_to_timestamp_tz_arg_dateutil(self, tzstr):
        tz = maybe_get_tz(tzstr)
        p = Period('1/1/2005', freq='M').to_timestamp(tz=tz)
        exp = Timestamp('1/1/2005', tz='UTC').tz_convert(tzstr)
        assert p == exp
        assert p.tz == dateutil_gettz(tzstr.split('/', 1)[1])
        assert p.tz == exp.tz

        p = Period('1/1/2005', freq='M').to_timestamp(freq='3H', tz=tz)
        exp = Timestamp('1/1/2005', tz='UTC').tz_convert(tzstr)
        assert p == exp
        assert p.tz == dateutil_gettz(tzstr.split('/', 1)[1])
        assert p.tz == exp.tz

    def test_to_timestamp_tz_arg_dateutil_from_string(self):
        p = Period('1/1/2005',
                   freq='M').to_timestamp(tz='dateutil/Europe/Brussels')
        assert p.tz == dateutil_gettz('Europe/Brussels')

    def test_to_timestamp_mult(self):
        p = Period('2011-01', freq='M')
        assert p.to_timestamp(how='S') == Timestamp('2011-01-01')
        expected = Timestamp('2011-02-01') - Timedelta(1, 'ns')
        assert p.to_timestamp(how='E') == expected

        p = Period('2011-01', freq='3M')
        assert p.to_timestamp(how='S') == Timestamp('2011-01-01')
        expected = Timestamp('2011-04-01') - Timedelta(1, 'ns')
        assert p.to_timestamp(how='E') == expected

    def test_to_timestamp(self):
        p = Period('1982', freq='A')
        start_ts = p.to_timestamp(how='S')
        aliases = ['s', 'StarT', 'BEGIn']
        for a in aliases:
            assert start_ts == p.to_timestamp('D', how=a)
            # freq with mult should not affect to the result
            assert start_ts == p.to_timestamp('3D', how=a)

        end_ts = p.to_timestamp(how='E')
        aliases = ['e', 'end', 'FINIsH']
        for a in aliases:
            assert end_ts == p.to_timestamp('D', how=a)
            assert end_ts == p.to_timestamp('3D', how=a)

        from_lst = ['A', 'Q', 'M', 'W', 'B', 'D', 'H', 'Min', 'S']

        def _ex(p):
            return Timestamp((p + p.freq).start_time.value - 1)

        for i, fcode in enumerate(from_lst):
            p = Period('1982', freq=fcode)
            result = p.to_timestamp().to_period(fcode)
            assert result == p

            assert p.start_time == p.to_timestamp(how='S')

            assert p.end_time == _ex(p)

        # Frequency other than daily

        p = Period('1985', freq='A')

        result = p.to_timestamp('H', how='end')
        expected = Timestamp(1986, 1, 1) - Timedelta(1, 'ns')
        assert result == expected
        result = p.to_timestamp('3H', how='end')
        assert result == expected

        result = p.to_timestamp('T', how='end')
        expected = Timestamp(1986, 1, 1) - Timedelta(1, 'ns')
        assert result == expected
        result = p.to_timestamp('2T', how='end')
        assert result == expected

        result = p.to_timestamp(how='end')
        expected = Timestamp(1986, 1, 1) - Timedelta(1, 'ns')
        assert result == expected

        expected = datetime(1985, 1, 1)
        result = p.to_timestamp('H', how='start')
        assert result == expected
        result = p.to_timestamp('T', how='start')
        assert result == expected
        result = p.to_timestamp('S', how='start')
        assert result == expected
        result = p.to_timestamp('3H', how='start')
        assert result == expected
        result = p.to_timestamp('5S', how='start')
        assert result == expected

    # --------------------------------------------------------------
    # Rendering: __repr__, strftime, etc

    def test_repr(self):
        p = Period('Jan-2000')
        assert '2000-01' in repr(p)

        p = Period('2000-12-15')
        assert '2000-12-15' in repr(p)

    def test_repr_nat(self):
        p = Period('nat', freq='M')
        assert repr(NaT) in repr(p)

    def test_millisecond_repr(self):
        p = Period('2000-01-01 12:15:02.123')

        assert repr(p) == "Period('2000-01-01 12:15:02.123', 'L')"

    def test_microsecond_repr(self):
        p = Period('2000-01-01 12:15:02.123567')

        assert repr(p) == "Period('2000-01-01 12:15:02.123567', 'U')"

    def test_strftime(self):
        # GH#3363
        p = Period('2000-1-1 12:34:12', freq='S')
        res = p.strftime('%Y-%m-%d %H:%M:%S')
        assert res == '2000-01-01 12:34:12'
        assert isinstance(res, text_type)


class TestPeriodProperties(object):
    "Test properties such as year, month, weekday, etc...."

    @pytest.mark.parametrize('freq', ['A', 'M', 'D', 'H'])
    def test_is_leap_year(self, freq):
        # GH 13727
        p = Period('2000-01-01 00:00:00', freq=freq)
        assert p.is_leap_year
        assert isinstance(p.is_leap_year, bool)

        p = Period('1999-01-01 00:00:00', freq=freq)
        assert not p.is_leap_year

        p = Period('2004-01-01 00:00:00', freq=freq)
        assert p.is_leap_year

        p = Period('2100-01-01 00:00:00', freq=freq)
        assert not p.is_leap_year

    def test_quarterly_negative_ordinals(self):
        p = Period(ordinal=-1, freq='Q-DEC')
        assert p.year == 1969
        assert p.quarter == 4
        assert isinstance(p, Period)

        p = Period(ordinal=-2, freq='Q-DEC')
        assert p.year == 1969
        assert p.quarter == 3
        assert isinstance(p, Period)

        p = Period(ordinal=-2, freq='M')
        assert p.year == 1969
        assert p.month == 11
        assert isinstance(p, Period)

    def test_freq_str(self):
        i1 = Period('1982', freq='Min')
        assert i1.freq == offsets.Minute()
        assert i1.freqstr == 'T'

    def test_period_deprecated_freq(self):
        cases = {"M": ["MTH", "MONTH", "MONTHLY", "Mth", "month", "monthly"],
                 "B": ["BUS", "BUSINESS", "BUSINESSLY", "WEEKDAY", "bus"],
                 "D": ["DAY", "DLY", "DAILY", "Day", "Dly", "Daily"],
                 "H": ["HR", "HOUR", "HRLY", "HOURLY", "hr", "Hour", "HRly"],
                 "T": ["minute", "MINUTE", "MINUTELY", "minutely"],
                 "S": ["sec", "SEC", "SECOND", "SECONDLY", "second"],
                 "L": ["MILLISECOND", "MILLISECONDLY", "millisecond"],
                 "U": ["MICROSECOND", "MICROSECONDLY", "microsecond"],
                 "N": ["NANOSECOND", "NANOSECONDLY", "nanosecond"]}

        msg = INVALID_FREQ_ERR_MSG
        for exp, freqs in iteritems(cases):
            for freq in freqs:
                with pytest.raises(ValueError, match=msg):
                    Period('2016-03-01 09:00', freq=freq)
                with pytest.raises(ValueError, match=msg):
                    Period(ordinal=1, freq=freq)

            # check supported freq-aliases still works
            p1 = Period('2016-03-01 09:00', freq=exp)
            p2 = Period(ordinal=1, freq=exp)
            assert isinstance(p1, Period)
            assert isinstance(p2, Period)

    def test_start_time(self):
        freq_lst = ['A', 'Q', 'M', 'D', 'H', 'T', 'S']
        xp = datetime(2012, 1, 1)
        for f in freq_lst:
            p = Period('2012', freq=f)
            assert p.start_time == xp
        assert Period('2012', freq='B').start_time == datetime(2012, 1, 2)
        assert Period('2012', freq='W').start_time == datetime(2011, 12, 26)

    def test_end_time(self):
        p = Period('2012', freq='A')

        def _ex(*args):
            return Timestamp(Timestamp(datetime(*args)).value - 1)

        xp = _ex(2013, 1, 1)
        assert xp == p.end_time

        p = Period('2012', freq='Q')
        xp = _ex(2012, 4, 1)
        assert xp == p.end_time

        p = Period('2012', freq='M')
        xp = _ex(2012, 2, 1)
        assert xp == p.end_time

        p = Period('2012', freq='D')
        xp = _ex(2012, 1, 2)
        assert xp == p.end_time

        p = Period('2012', freq='H')
        xp = _ex(2012, 1, 1, 1)
        assert xp == p.end_time

        p = Period('2012', freq='B')
        xp = _ex(2012, 1, 3)
        assert xp == p.end_time

        p = Period('2012', freq='W')
        xp = _ex(2012, 1, 2)
        assert xp == p.end_time

        # Test for GH 11738
        p = Period('2012', freq='15D')
        xp = _ex(2012, 1, 16)
        assert xp == p.end_time

        p = Period('2012', freq='1D1H')
        xp = _ex(2012, 1, 2, 1)
        assert xp == p.end_time

        p = Period('2012', freq='1H1D')
        xp = _ex(2012, 1, 2, 1)
        assert xp == p.end_time

    def test_anchor_week_end_time(self):
        def _ex(*args):
            return Timestamp(Timestamp(datetime(*args)).value - 1)

        p = Period('2013-1-1', 'W-SAT')
        xp = _ex(2013, 1, 6)
        assert p.end_time == xp

    def test_properties_annually(self):
        # Test properties on Periods with annually frequency.
        a_date = Period(freq='A', year=2007)
        assert a_date.year == 2007

    def test_properties_quarterly(self):
        # Test properties on Periods with daily frequency.
        qedec_date = Period(freq="Q-DEC", year=2007, quarter=1)
        qejan_date = Period(freq="Q-JAN", year=2007, quarter=1)
        qejun_date = Period(freq="Q-JUN", year=2007, quarter=1)
        #
        for x in range(3):
            for qd in (qedec_date, qejan_date, qejun_date):
                assert (qd + x).qyear == 2007
                assert (qd + x).quarter == x + 1

    def test_properties_monthly(self):
        # Test properties on Periods with daily frequency.
        m_date = Period(freq='M', year=2007, month=1)
        for x in range(11):
            m_ival_x = m_date + x
            assert m_ival_x.year == 2007
            if 1 <= x + 1 <= 3:
                assert m_ival_x.quarter == 1
            elif 4 <= x + 1 <= 6:
                assert m_ival_x.quarter == 2
            elif 7 <= x + 1 <= 9:
                assert m_ival_x.quarter == 3
            elif 10 <= x + 1 <= 12:
                assert m_ival_x.quarter == 4
            assert m_ival_x.month == x + 1

    def test_properties_weekly(self):
        # Test properties on Periods with daily frequency.
        w_date = Period(freq='W', year=2007, month=1, day=7)
        #
        assert w_date.year == 2007
        assert w_date.quarter == 1
        assert w_date.month == 1
        assert w_date.week == 1
        assert (w_date - 1).week == 52
        assert w_date.days_in_month == 31
        assert Period(freq='W', year=2012,
                      month=2, day=1).days_in_month == 29

    def test_properties_weekly_legacy(self):
        # Test properties on Periods with daily frequency.
        w_date = Period(freq='W', year=2007, month=1, day=7)
        assert w_date.year == 2007
        assert w_date.quarter == 1
        assert w_date.month == 1
        assert w_date.week == 1
        assert (w_date - 1).week == 52
        assert w_date.days_in_month == 31

        exp = Period(freq='W', year=2012, month=2, day=1)
        assert exp.days_in_month == 29

        msg = INVALID_FREQ_ERR_MSG
        with pytest.raises(ValueError, match=msg):
            Period(freq='WK', year=2007, month=1, day=7)

    def test_properties_daily(self):
        # Test properties on Periods with daily frequency.
        b_date = Period(freq='B', year=2007, month=1, day=1)
        #
        assert b_date.year == 2007
        assert b_date.quarter == 1
        assert b_date.month == 1
        assert b_date.day == 1
        assert b_date.weekday == 0
        assert b_date.dayofyear == 1
        assert b_date.days_in_month == 31
        assert Period(freq='B', year=2012,
                      month=2, day=1).days_in_month == 29

        d_date = Period(freq='D', year=2007, month=1, day=1)

        assert d_date.year == 2007
        assert d_date.quarter == 1
        assert d_date.month == 1
        assert d_date.day == 1
        assert d_date.weekday == 0
        assert d_date.dayofyear == 1
        assert d_date.days_in_month == 31
        assert Period(freq='D', year=2012, month=2,
                      day=1).days_in_month == 29

    def test_properties_hourly(self):
        # Test properties on Periods with hourly frequency.
        h_date1 = Period(freq='H', year=2007, month=1, day=1, hour=0)
        h_date2 = Period(freq='2H', year=2007, month=1, day=1, hour=0)

        for h_date in [h_date1, h_date2]:
            assert h_date.year == 2007
            assert h_date.quarter == 1
            assert h_date.month == 1
            assert h_date.day == 1
            assert h_date.weekday == 0
            assert h_date.dayofyear == 1
            assert h_date.hour == 0
            assert h_date.days_in_month == 31
            assert Period(freq='H', year=2012, month=2, day=1,
                          hour=0).days_in_month == 29

    def test_properties_minutely(self):
        # Test properties on Periods with minutely frequency.
        t_date = Period(freq='Min', year=2007, month=1, day=1, hour=0,
                        minute=0)
        #
        assert t_date.quarter == 1
        assert t_date.month == 1
        assert t_date.day == 1
        assert t_date.weekday == 0
        assert t_date.dayofyear == 1
        assert t_date.hour == 0
        assert t_date.minute == 0
        assert t_date.days_in_month == 31
        assert Period(freq='D', year=2012, month=2, day=1, hour=0,
                      minute=0).days_in_month == 29

    def test_properties_secondly(self):
        # Test properties on Periods with secondly frequency.
        s_date = Period(freq='Min', year=2007, month=1, day=1, hour=0,
                        minute=0, second=0)
        #
        assert s_date.year == 2007
        assert s_date.quarter == 1
        assert s_date.month == 1
        assert s_date.day == 1
        assert s_date.weekday == 0
        assert s_date.dayofyear == 1
        assert s_date.hour == 0
        assert s_date.minute == 0
        assert s_date.second == 0
        assert s_date.days_in_month == 31
        assert Period(freq='Min', year=2012, month=2, day=1, hour=0,
                      minute=0, second=0).days_in_month == 29


class TestPeriodField(object):

    def test_get_period_field_array_raises_on_out_of_range(self):
        pytest.raises(ValueError, libperiod.get_period_field_arr, -1,
                      np.empty(1), 0)


class TestComparisons(object):

    def setup_method(self, method):
        self.january1 = Period('2000-01', 'M')
        self.january2 = Period('2000-01', 'M')
        self.february = Period('2000-02', 'M')
        self.march = Period('2000-03', 'M')
        self.day = Period('2012-01-01', 'D')

    def test_equal(self):
        assert self.january1 == self.january2

    def test_equal_Raises_Value(self):
        with pytest.raises(period.IncompatibleFrequency):
            self.january1 == self.day

    def test_notEqual(self):
        assert self.january1 != 1
        assert self.january1 != self.february

    def test_greater(self):
        assert self.february > self.january1

    def test_greater_Raises_Value(self):
        with pytest.raises(period.IncompatibleFrequency):
            self.january1 > self.day

    def test_greater_Raises_Type(self):
        with pytest.raises(TypeError):
            self.january1 > 1

    def test_greaterEqual(self):
        assert self.january1 >= self.january2

    def test_greaterEqual_Raises_Value(self):
        with pytest.raises(period.IncompatibleFrequency):
            self.january1 >= self.day

        with pytest.raises(TypeError):
            print(self.january1 >= 1)

    def test_smallerEqual(self):
        assert self.january1 <= self.january2

    def test_smallerEqual_Raises_Value(self):
        with pytest.raises(period.IncompatibleFrequency):
            self.january1 <= self.day

    def test_smallerEqual_Raises_Type(self):
        with pytest.raises(TypeError):
            self.january1 <= 1

    def test_smaller(self):
        assert self.january1 < self.february

    def test_smaller_Raises_Value(self):
        with pytest.raises(period.IncompatibleFrequency):
            self.january1 < self.day

    def test_smaller_Raises_Type(self):
        with pytest.raises(TypeError):
            self.january1 < 1

    def test_sort(self):
        periods = [self.march, self.january1, self.february]
        correctPeriods = [self.january1, self.february, self.march]
        assert sorted(periods) == correctPeriods

    def test_period_nat_comp(self):
        p_nat = Period('NaT', freq='D')
        p = Period('2011-01-01', freq='D')

        nat = Timestamp('NaT')
        t = Timestamp('2011-01-01')
        # confirm Period('NaT') work identical with Timestamp('NaT')
        for left, right in [(p_nat, p), (p, p_nat), (p_nat, p_nat), (nat, t),
                            (t, nat), (nat, nat)]:
            assert not left < right
            assert not left > right
            assert not left == right
            assert left != right
            assert not left <= right
            assert not left >= right


class TestArithmetic(object):

    def test_sub_delta(self):
        left, right = Period('2011', freq='A'), Period('2007', freq='A')
        result = left - right
        assert result == 4 * right.freq

        with pytest.raises(period.IncompatibleFrequency):
            left - Period('2007-01', freq='M')

    def test_add_integer(self):
        per1 = Period(freq='D', year=2008, month=1, day=1)
        per2 = Period(freq='D', year=2008, month=1, day=2)
        assert per1 + 1 == per2
        assert 1 + per1 == per2

    def test_add_sub_nat(self):
        # GH#13071
        p = Period('2011-01', freq='M')
        assert p + NaT is NaT
        assert NaT + p is NaT
        assert p - NaT is NaT
        assert NaT - p is NaT

        p = Period('NaT', freq='M')
        assert p + NaT is NaT
        assert NaT + p is NaT
        assert p - NaT is NaT
        assert NaT - p is NaT

    def test_add_invalid(self):
        # GH#4731
        per1 = Period(freq='D', year=2008, month=1, day=1)
        per2 = Period(freq='D', year=2008, month=1, day=2)

        msg = r"unsupported operand type\(s\)"
        with pytest.raises(TypeError, match=msg):
            per1 + "str"
        with pytest.raises(TypeError, match=msg):
            "str" + per1
        with pytest.raises(TypeError, match=msg):
            per1 + per2

    boxes = [lambda x: x, lambda x: pd.Series([x]), lambda x: pd.Index([x])]
    ids = ['identity', 'Series', 'Index']

    @pytest.mark.parametrize('lbox', boxes, ids=ids)
    @pytest.mark.parametrize('rbox', boxes, ids=ids)
    def test_add_timestamp_raises(self, rbox, lbox):
        # GH#17983
        ts = Timestamp('2017')
        per = Period('2017', freq='M')

        # We may get a different message depending on which class raises
        # the error.
        msg = (r"cannot add|unsupported operand|"
               r"can only operate on a|incompatible type|"
               r"ufunc add cannot use operands")
        with pytest.raises(TypeError, match=msg):
            lbox(ts) + rbox(per)

        with pytest.raises(TypeError, match=msg):
            lbox(per) + rbox(ts)

        with pytest.raises(TypeError, match=msg):
            lbox(per) + rbox(per)

    def test_sub(self):
        per1 = Period('2011-01-01', freq='D')
        per2 = Period('2011-01-15', freq='D')

        off = per1.freq
        assert per1 - per2 == -14 * off
        assert per2 - per1 == 14 * off

        msg = r"Input has different freq=M from Period\(freq=D\)"
        with pytest.raises(period.IncompatibleFrequency, match=msg):
            per1 - Period('2011-02', freq='M')

    @pytest.mark.parametrize('n', [1, 2, 3, 4])
    def test_sub_n_gt_1_ticks(self, tick_classes, n):
        # GH 23878
        p1 = pd.Period('19910905', freq=tick_classes(n))
        p2 = pd.Period('19920406', freq=tick_classes(n))

        expected = (pd.Period(str(p2), freq=p2.freq.base)
                    - pd.Period(str(p1), freq=p1.freq.base))

        assert (p2 - p1) == expected

    @pytest.mark.parametrize('normalize', [True, False])
    @pytest.mark.parametrize('n', [1, 2, 3, 4])
    @pytest.mark.parametrize('offset, kwd_name', [
        (pd.offsets.YearEnd, 'month'),
        (pd.offsets.QuarterEnd, 'startingMonth'),
        (pd.offsets.MonthEnd, None),
        (pd.offsets.Week, 'weekday')
    ])
    def test_sub_n_gt_1_offsets(self, offset, kwd_name, n, normalize):
        # GH 23878
        kwds = {kwd_name: 3} if kwd_name is not None else {}
        p1_d = '19910905'
        p2_d = '19920406'
        p1 = pd.Period(p1_d, freq=offset(n, normalize, **kwds))
        p2 = pd.Period(p2_d, freq=offset(n, normalize, **kwds))

        expected = (pd.Period(p2_d, freq=p2.freq.base)
                    - pd.Period(p1_d, freq=p1.freq.base))

        assert (p2 - p1) == expected

    def test_add_offset(self):
        # freq is DateOffset
        for freq in ['A', '2A', '3A']:
            p = Period('2011', freq=freq)
            exp = Period('2013', freq=freq)
            assert p + offsets.YearEnd(2) == exp
            assert offsets.YearEnd(2) + p == exp

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p + o

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    with pytest.raises(period.IncompatibleFrequency):
                        o + p

        for freq in ['M', '2M', '3M']:
            p = Period('2011-03', freq=freq)
            exp = Period('2011-05', freq=freq)
            assert p + offsets.MonthEnd(2) == exp
            assert offsets.MonthEnd(2) + p == exp

            exp = Period('2012-03', freq=freq)
            assert p + offsets.MonthEnd(12) == exp
            assert offsets.MonthEnd(12) + p == exp

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p + o

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    with pytest.raises(period.IncompatibleFrequency):
                        o + p

        # freq is Tick
        for freq in ['D', '2D', '3D']:
            p = Period('2011-04-01', freq=freq)

            exp = Period('2011-04-06', freq=freq)
            assert p + offsets.Day(5) == exp
            assert offsets.Day(5) + p == exp

            exp = Period('2011-04-02', freq=freq)
            assert p + offsets.Hour(24) == exp
            assert offsets.Hour(24) + p == exp

            exp = Period('2011-04-03', freq=freq)
            assert p + np.timedelta64(2, 'D') == exp
            with pytest.raises(TypeError):
                np.timedelta64(2, 'D') + p

            exp = Period('2011-04-02', freq=freq)
            assert p + np.timedelta64(3600 * 24, 's') == exp
            with pytest.raises(TypeError):
                np.timedelta64(3600 * 24, 's') + p

            exp = Period('2011-03-30', freq=freq)
            assert p + timedelta(-2) == exp
            assert timedelta(-2) + p == exp

            exp = Period('2011-04-03', freq=freq)
            assert p + timedelta(hours=48) == exp
            assert timedelta(hours=48) + p == exp

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(4, 'h'),
                      timedelta(hours=23)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p + o

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    with pytest.raises(period.IncompatibleFrequency):
                        o + p

        for freq in ['H', '2H', '3H']:
            p = Period('2011-04-01 09:00', freq=freq)

            exp = Period('2011-04-03 09:00', freq=freq)
            assert p + offsets.Day(2) == exp
            assert offsets.Day(2) + p == exp

            exp = Period('2011-04-01 12:00', freq=freq)
            assert p + offsets.Hour(3) == exp
            assert offsets.Hour(3) + p == exp

            exp = Period('2011-04-01 12:00', freq=freq)
            assert p + np.timedelta64(3, 'h') == exp
            with pytest.raises(TypeError):
                np.timedelta64(3, 'h') + p

            exp = Period('2011-04-01 10:00', freq=freq)
            assert p + np.timedelta64(3600, 's') == exp
            with pytest.raises(TypeError):
                np.timedelta64(3600, 's') + p

            exp = Period('2011-04-01 11:00', freq=freq)
            assert p + timedelta(minutes=120) == exp
            assert timedelta(minutes=120) + p == exp

            exp = Period('2011-04-05 12:00', freq=freq)
            assert p + timedelta(days=4, minutes=180) == exp
            assert timedelta(days=4, minutes=180) + p == exp

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(3200, 's'),
                      timedelta(hours=23, minutes=30)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p + o

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    with pytest.raises(period.IncompatibleFrequency):
                        o + p

    def test_add_offset_nat(self):
        # freq is DateOffset
        for freq in ['A', '2A', '3A']:
            p = Period('NaT', freq=freq)
            for o in [offsets.YearEnd(2)]:
                assert p + o is NaT
                assert o + p is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

        for freq in ['M', '2M', '3M']:
            p = Period('NaT', freq=freq)
            for o in [offsets.MonthEnd(2), offsets.MonthEnd(12)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

        # freq is Tick
        for freq in ['D', '2D', '3D']:
            p = Period('NaT', freq=freq)
            for o in [offsets.Day(5), offsets.Hour(24), np.timedelta64(2, 'D'),
                      np.timedelta64(3600 * 24, 's'), timedelta(-2),
                      timedelta(hours=48)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(4, 'h'),
                      timedelta(hours=23)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

        for freq in ['H', '2H', '3H']:
            p = Period('NaT', freq=freq)
            for o in [offsets.Day(2), offsets.Hour(3), np.timedelta64(3, 'h'),
                      np.timedelta64(3600, 's'), timedelta(minutes=120),
                      timedelta(days=4, minutes=180)]:
                assert p + o is NaT

                if not isinstance(o, np.timedelta64):
                    assert o + p is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(3200, 's'),
                      timedelta(hours=23, minutes=30)]:
                assert p + o is NaT

                if isinstance(o, np.timedelta64):
                    with pytest.raises(TypeError):
                        o + p
                else:
                    assert o + p is NaT

    def test_sub_offset(self):
        # freq is DateOffset
        for freq in ['A', '2A', '3A']:
            p = Period('2011', freq=freq)
            assert p - offsets.YearEnd(2) == Period('2009', freq=freq)

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p - o

        for freq in ['M', '2M', '3M']:
            p = Period('2011-03', freq=freq)
            assert p - offsets.MonthEnd(2) == Period('2011-01', freq=freq)
            assert p - offsets.MonthEnd(12) == Period('2010-03', freq=freq)

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p - o

        # freq is Tick
        for freq in ['D', '2D', '3D']:
            p = Period('2011-04-01', freq=freq)
            assert p - offsets.Day(5) == Period('2011-03-27', freq=freq)
            assert p - offsets.Hour(24) == Period('2011-03-31', freq=freq)
            assert p - np.timedelta64(2, 'D') == Period(
                '2011-03-30', freq=freq)
            assert p - np.timedelta64(3600 * 24, 's') == Period(
                '2011-03-31', freq=freq)
            assert p - timedelta(-2) == Period('2011-04-03', freq=freq)
            assert p - timedelta(hours=48) == Period('2011-03-30', freq=freq)

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(4, 'h'),
                      timedelta(hours=23)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p - o

        for freq in ['H', '2H', '3H']:
            p = Period('2011-04-01 09:00', freq=freq)
            assert p - offsets.Day(2) == Period('2011-03-30 09:00', freq=freq)
            assert p - offsets.Hour(3) == Period('2011-04-01 06:00', freq=freq)
            assert p - np.timedelta64(3, 'h') == Period(
                '2011-04-01 06:00', freq=freq)
            assert p - np.timedelta64(3600, 's') == Period(
                '2011-04-01 08:00', freq=freq)
            assert p - timedelta(minutes=120) == Period(
                '2011-04-01 07:00', freq=freq)
            assert p - timedelta(days=4, minutes=180) == Period(
                '2011-03-28 06:00', freq=freq)

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(3200, 's'),
                      timedelta(hours=23, minutes=30)]:
                with pytest.raises(period.IncompatibleFrequency):
                    p - o

    def test_sub_offset_nat(self):
        # freq is DateOffset
        for freq in ['A', '2A', '3A']:
            p = Period('NaT', freq=freq)
            for o in [offsets.YearEnd(2)]:
                assert p - o is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                assert p - o is NaT

        for freq in ['M', '2M', '3M']:
            p = Period('NaT', freq=freq)
            for o in [offsets.MonthEnd(2), offsets.MonthEnd(12)]:
                assert p - o is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(365, 'D'),
                      timedelta(365)]:
                assert p - o is NaT

        # freq is Tick
        for freq in ['D', '2D', '3D']:
            p = Period('NaT', freq=freq)
            for o in [offsets.Day(5), offsets.Hour(24), np.timedelta64(2, 'D'),
                      np.timedelta64(3600 * 24, 's'), timedelta(-2),
                      timedelta(hours=48)]:
                assert p - o is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(4, 'h'),
                      timedelta(hours=23)]:
                assert p - o is NaT

        for freq in ['H', '2H', '3H']:
            p = Period('NaT', freq=freq)
            for o in [offsets.Day(2), offsets.Hour(3), np.timedelta64(3, 'h'),
                      np.timedelta64(3600, 's'), timedelta(minutes=120),
                      timedelta(days=4, minutes=180)]:
                assert p - o is NaT

            for o in [offsets.YearBegin(2), offsets.MonthBegin(1),
                      offsets.Minute(), np.timedelta64(3200, 's'),
                      timedelta(hours=23, minutes=30)]:
                assert p - o is NaT

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_nat_ops(self, freq):
        p = Period('NaT', freq=freq)
        assert p + 1 is NaT
        assert 1 + p is NaT
        assert p - 1 is NaT
        assert p - Period('2011-01', freq=freq) is NaT
        assert Period('2011-01', freq=freq) - p is NaT

    def test_period_ops_offset(self):
        p = Period('2011-04-01', freq='D')
        result = p + offsets.Day()
        exp = Period('2011-04-02', freq='D')
        assert result == exp

        result = p - offsets.Day(2)
        exp = Period('2011-03-30', freq='D')
        assert result == exp

        msg = r"Input cannot be converted to Period\(freq=D\)"
        with pytest.raises(period.IncompatibleFrequency, match=msg):
            p + offsets.Hour(2)

        with pytest.raises(period.IncompatibleFrequency, match=msg):
            p - offsets.Hour(2)


def test_period_immutable():
    # see gh-17116
    per = Period('2014Q1')
    with pytest.raises(AttributeError):
        per.ordinal = 14

    freq = per.freq
    with pytest.raises(AttributeError):
        per.freq = 2 * freq


# TODO: This doesn't fail on all systems; track down which
@pytest.mark.xfail(reason="Parses as Jan 1, 0007 on some systems",
                   strict=False)
def test_small_year_parsing():
    per1 = Period('0001-01-07', 'D')
    assert per1.year == 1
    assert per1.day == 7