test_period.py

# -*- coding: utf-8 -*-
# Arithmetc tests for DataFrame/Series/Index/Array classes that should
# behave identically.
# Specifically for Period dtype
import operator

import numpy as np
import pytest

import pandas as pd
import pandas.util.testing as tm

from pandas._libs.tslibs.period import IncompatibleFrequency
from pandas.errors import PerformanceWarning

from pandas.core import ops
from pandas import Period, PeriodIndex, period_range, Series
from pandas.tseries.frequencies import to_offset


# ------------------------------------------------------------------
# Comparisons

class TestPeriodIndexComparisons(object):
    def test_pi_cmp_period(self):
        idx = period_range('2007-01', periods=20, freq='M')

        result = idx < idx[10]
        exp = idx.values < idx.values[10]
        tm.assert_numpy_array_equal(result, exp)

    # TODO: moved from test_datetime64; de-duplicate with version below
    def test_parr_cmp_period_scalar2(self, box_with_array):
        xbox = box_with_array if box_with_array is not pd.Index else np.ndarray

        pi = pd.period_range('2000-01-01', periods=10, freq='D')

        val = Period('2000-01-04', freq='D')
        expected = [x > val for x in pi]

        ser = tm.box_expected(pi, box_with_array)
        expected = tm.box_expected(expected, xbox)
        result = ser > val
        tm.assert_equal(result, expected)

        val = pi[5]
        result = ser > val
        expected = [x > val for x in pi]
        expected = tm.box_expected(expected, xbox)
        tm.assert_equal(result, expected)

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_parr_cmp_period_scalar(self, freq, box_with_array):
        # GH#13200
        xbox = np.ndarray if box_with_array is pd.Index else box_with_array

        base = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                           freq=freq)
        base = tm.box_expected(base, box_with_array)
        per = Period('2011-02', freq=freq)

        exp = np.array([False, True, False, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base == per, exp)
        tm.assert_equal(per == base, exp)

        exp = np.array([True, False, True, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base != per, exp)
        tm.assert_equal(per != base, exp)

        exp = np.array([False, False, True, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base > per, exp)
        tm.assert_equal(per < base, exp)

        exp = np.array([True, False, False, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base < per, exp)
        tm.assert_equal(per > base, exp)

        exp = np.array([False, True, True, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base >= per, exp)
        tm.assert_equal(per <= base, exp)

        exp = np.array([True, True, False, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base <= per, exp)
        tm.assert_equal(per >= base, exp)

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_parr_cmp_pi(self, freq, box_with_array):
        # GH#13200
        xbox = np.ndarray if box_with_array is pd.Index else box_with_array

        base = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                           freq=freq)
        base = tm.box_expected(base, box_with_array)

        # TODO: could also box idx?
        idx = PeriodIndex(['2011-02', '2011-01', '2011-03', '2011-05'],
                          freq=freq)

        exp = np.array([False, False, True, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base == idx, exp)

        exp = np.array([True, True, False, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base != idx, exp)

        exp = np.array([False, True, False, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base > idx, exp)

        exp = np.array([True, False, False, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base < idx, exp)

        exp = np.array([False, True, True, False])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base >= idx, exp)

        exp = np.array([True, False, True, True])
        exp = tm.box_expected(exp, xbox)
        tm.assert_equal(base <= idx, exp)

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_parr_cmp_pi_mismatched_freq_raises(self, freq, box_with_array):
        # GH#13200
        # different base freq
        base = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                           freq=freq)
        base = tm.box_expected(base, box_with_array)

        msg = "Input has different freq=A-DEC from "
        with pytest.raises(IncompatibleFrequency, match=msg):
            base <= Period('2011', freq='A')

        with pytest.raises(IncompatibleFrequency, match=msg):
            Period('2011', freq='A') >= base

        # TODO: Could parametrize over boxes for idx?
        idx = PeriodIndex(['2011', '2012', '2013', '2014'], freq='A')
        with pytest.raises(IncompatibleFrequency, match=msg):
            base <= idx

        # Different frequency
        msg = "Input has different freq=4M from "
        with pytest.raises(IncompatibleFrequency, match=msg):
            base <= Period('2011', freq='4M')

        with pytest.raises(IncompatibleFrequency, match=msg):
            Period('2011', freq='4M') >= base

        idx = PeriodIndex(['2011', '2012', '2013', '2014'], freq='4M')
        with pytest.raises(IncompatibleFrequency, match=msg):
            base <= idx

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_pi_cmp_nat(self, freq):
        idx1 = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-05'], freq=freq)

        result = idx1 > Period('2011-02', freq=freq)
        exp = np.array([False, False, False, True])
        tm.assert_numpy_array_equal(result, exp)
        result = Period('2011-02', freq=freq) < idx1
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 == Period('NaT', freq=freq)
        exp = np.array([False, False, False, False])
        tm.assert_numpy_array_equal(result, exp)
        result = Period('NaT', freq=freq) == idx1
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 != Period('NaT', freq=freq)
        exp = np.array([True, True, True, True])
        tm.assert_numpy_array_equal(result, exp)
        result = Period('NaT', freq=freq) != idx1
        tm.assert_numpy_array_equal(result, exp)

        idx2 = PeriodIndex(['2011-02', '2011-01', '2011-04', 'NaT'], freq=freq)
        result = idx1 < idx2
        exp = np.array([True, False, False, False])
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 == idx2
        exp = np.array([False, False, False, False])
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 != idx2
        exp = np.array([True, True, True, True])
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 == idx1
        exp = np.array([True, True, False, True])
        tm.assert_numpy_array_equal(result, exp)

        result = idx1 != idx1
        exp = np.array([False, False, True, False])
        tm.assert_numpy_array_equal(result, exp)

    @pytest.mark.parametrize('freq', ['M', '2M', '3M'])
    def test_pi_cmp_nat_mismatched_freq_raises(self, freq):
        idx1 = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-05'], freq=freq)

        diff = PeriodIndex(['2011-02', '2011-01', '2011-04', 'NaT'], freq='4M')
        msg = "Input has different freq=4M from PeriodIndex"
        with pytest.raises(IncompatibleFrequency, match=msg):
            idx1 > diff

        with pytest.raises(IncompatibleFrequency, match=msg):
            idx1 == diff

    # TODO: De-duplicate with test_pi_cmp_nat
    @pytest.mark.parametrize('dtype', [object, None])
    def test_comp_nat(self, dtype):
        left = pd.PeriodIndex([pd.Period('2011-01-01'), pd.NaT,
                               pd.Period('2011-01-03')])
        right = pd.PeriodIndex([pd.NaT, pd.NaT, pd.Period('2011-01-03')])

        if dtype is not None:
            left = left.astype(dtype)
            right = right.astype(dtype)

        result = left == right
        expected = np.array([False, False, True])
        tm.assert_numpy_array_equal(result, expected)

        result = left != right
        expected = np.array([True, True, False])
        tm.assert_numpy_array_equal(result, expected)

        expected = np.array([False, False, False])
        tm.assert_numpy_array_equal(left == pd.NaT, expected)
        tm.assert_numpy_array_equal(pd.NaT == right, expected)

        expected = np.array([True, True, True])
        tm.assert_numpy_array_equal(left != pd.NaT, expected)
        tm.assert_numpy_array_equal(pd.NaT != left, expected)

        expected = np.array([False, False, False])
        tm.assert_numpy_array_equal(left < pd.NaT, expected)
        tm.assert_numpy_array_equal(pd.NaT > left, expected)


class TestPeriodSeriesComparisons(object):
    def test_cmp_series_period_series_mixed_freq(self):
        # GH#13200
        base = Series([Period('2011', freq='A'),
                       Period('2011-02', freq='M'),
                       Period('2013', freq='A'),
                       Period('2011-04', freq='M')])

        ser = Series([Period('2012', freq='A'),
                      Period('2011-01', freq='M'),
                      Period('2013', freq='A'),
                      Period('2011-05', freq='M')])

        exp = Series([False, False, True, False])
        tm.assert_series_equal(base == ser, exp)

        exp = Series([True, True, False, True])
        tm.assert_series_equal(base != ser, exp)

        exp = Series([False, True, False, False])
        tm.assert_series_equal(base > ser, exp)

        exp = Series([True, False, False, True])
        tm.assert_series_equal(base < ser, exp)

        exp = Series([False, True, True, False])
        tm.assert_series_equal(base >= ser, exp)

        exp = Series([True, False, True, True])
        tm.assert_series_equal(base <= ser, exp)


# ------------------------------------------------------------------
# Arithmetic

class TestPeriodFrameArithmetic(object):

    def test_ops_frame_period(self):
        # GH#13043
        df = pd.DataFrame({'A': [pd.Period('2015-01', freq='M'),
                                 pd.Period('2015-02', freq='M')],
                           'B': [pd.Period('2014-01', freq='M'),
                                 pd.Period('2014-02', freq='M')]})
        assert df['A'].dtype == 'Period[M]'
        assert df['B'].dtype == 'Period[M]'

        p = pd.Period('2015-03', freq='M')
        off = p.freq
        # dtype will be object because of original dtype
        exp = pd.DataFrame({'A': np.array([2 * off, 1 * off], dtype=object),
                            'B': np.array([14 * off, 13 * off], dtype=object)})
        tm.assert_frame_equal(p - df, exp)
        tm.assert_frame_equal(df - p, -1 * exp)

        df2 = pd.DataFrame({'A': [pd.Period('2015-05', freq='M'),
                                  pd.Period('2015-06', freq='M')],
                            'B': [pd.Period('2015-05', freq='M'),
                                  pd.Period('2015-06', freq='M')]})
        assert df2['A'].dtype == 'Period[M]'
        assert df2['B'].dtype == 'Period[M]'

        exp = pd.DataFrame({'A': np.array([4 * off, 4 * off], dtype=object),
                            'B': np.array([16 * off, 16 * off], dtype=object)})
        tm.assert_frame_equal(df2 - df, exp)
        tm.assert_frame_equal(df - df2, -1 * exp)


class TestPeriodIndexArithmetic(object):
    # ---------------------------------------------------------------
    # __add__/__sub__ with PeriodIndex
    # PeriodIndex + other is defined for integers and timedelta-like others
    # PeriodIndex - other is defined for integers, timedelta-like others,
    #   and PeriodIndex (with matching freq)

    def test_parr_add_iadd_parr_raises(self, box_with_array):
        rng = pd.period_range('1/1/2000', freq='D', periods=5)
        other = pd.period_range('1/6/2000', freq='D', periods=5)
        # TODO: parametrize over boxes for other?

        rng = tm.box_expected(rng, box_with_array)
        # An earlier implementation of PeriodIndex addition performed
        # a set operation (union).  This has since been changed to
        # raise a TypeError. See GH#14164 and GH#13077 for historical
        # reference.
        with pytest.raises(TypeError):
            rng + other

        with pytest.raises(TypeError):
            rng += other

    def test_pi_sub_isub_pi(self):
        # GH#20049
        # For historical reference see GH#14164, GH#13077.
        # PeriodIndex subtraction originally performed set difference,
        # then changed to raise TypeError before being implemented in GH#20049
        rng = pd.period_range('1/1/2000', freq='D', periods=5)
        other = pd.period_range('1/6/2000', freq='D', periods=5)

        off = rng.freq
        expected = pd.Index([-5 * off] * 5)
        result = rng - other
        tm.assert_index_equal(result, expected)

        rng -= other
        tm.assert_index_equal(rng, expected)

    def test_pi_sub_pi_with_nat(self):
        rng = pd.period_range('1/1/2000', freq='D', periods=5)
        other = rng[1:].insert(0, pd.NaT)
        assert other[1:].equals(rng[1:])

        result = rng - other
        off = rng.freq
        expected = pd.Index([pd.NaT, 0 * off, 0 * off, 0 * off, 0 * off])
        tm.assert_index_equal(result, expected)

    def test_parr_sub_pi_mismatched_freq(self, box_with_array):
        rng = pd.period_range('1/1/2000', freq='D', periods=5)
        other = pd.period_range('1/6/2000', freq='H', periods=5)
        # TODO: parametrize over boxes for other?

        rng = tm.box_expected(rng, box_with_array)
        with pytest.raises(IncompatibleFrequency):
            rng - other

    # -------------------------------------------------------------
    # Invalid Operations

    @pytest.mark.parametrize('other', [3.14, np.array([2.0, 3.0])])
    @pytest.mark.parametrize('op', [operator.add, ops.radd,
                                    operator.sub, ops.rsub])
    def test_parr_add_sub_float_raises(self, op, other, box_with_array):
        dti = pd.DatetimeIndex(['2011-01-01', '2011-01-02'], freq='D')
        pi = dti.to_period('D')
        pi = tm.box_expected(pi, box_with_array)
        with pytest.raises(TypeError):
            op(pi, other)

    @pytest.mark.parametrize('other', [pd.Timestamp.now(),
                                       pd.Timestamp.now().to_pydatetime(),
                                       pd.Timestamp.now().to_datetime64()])
    def test_parr_add_sub_datetime_scalar(self, other, box_with_array):
        # GH#23215
        rng = pd.period_range('1/1/2000', freq='D', periods=3)
        rng = tm.box_expected(rng, box_with_array)

        with pytest.raises(TypeError):
            rng + other
        with pytest.raises(TypeError):
            other + rng
        with pytest.raises(TypeError):
            rng - other
        with pytest.raises(TypeError):
            other - rng

    # -----------------------------------------------------------------
    # __add__/__sub__ with ndarray[datetime64] and ndarray[timedelta64]

    def test_parr_add_sub_dt64_array_raises(self, box_with_array):
        rng = pd.period_range('1/1/2000', freq='D', periods=3)
        dti = pd.date_range('2016-01-01', periods=3)
        dtarr = dti.values

        rng = tm.box_expected(rng, box_with_array)

        with pytest.raises(TypeError):
            rng + dtarr
        with pytest.raises(TypeError):
            dtarr + rng

        with pytest.raises(TypeError):
            rng - dtarr
        with pytest.raises(TypeError):
            dtarr - rng

    def test_pi_add_sub_td64_array_non_tick_raises(self):
        rng = pd.period_range('1/1/2000', freq='Q', periods=3)
        tdi = pd.TimedeltaIndex(['-1 Day', '-1 Day', '-1 Day'])
        tdarr = tdi.values

        with pytest.raises(IncompatibleFrequency):
            rng + tdarr
        with pytest.raises(IncompatibleFrequency):
            tdarr + rng

        with pytest.raises(IncompatibleFrequency):
            rng - tdarr
        with pytest.raises(TypeError):
            tdarr - rng

    def test_pi_add_sub_td64_array_tick(self):
        # PeriodIndex + Timedelta-like is allowed only with
        #   tick-like frequencies
        rng = pd.period_range('1/1/2000', freq='90D', periods=3)
        tdi = pd.TimedeltaIndex(['-1 Day', '-1 Day', '-1 Day'])
        tdarr = tdi.values

        expected = pd.period_range('12/31/1999', freq='90D', periods=3)
        result = rng + tdi
        tm.assert_index_equal(result, expected)
        result = rng + tdarr
        tm.assert_index_equal(result, expected)
        result = tdi + rng
        tm.assert_index_equal(result, expected)
        result = tdarr + rng
        tm.assert_index_equal(result, expected)

        expected = pd.period_range('1/2/2000', freq='90D', periods=3)

        result = rng - tdi
        tm.assert_index_equal(result, expected)
        result = rng - tdarr
        tm.assert_index_equal(result, expected)

        with pytest.raises(TypeError):
            tdarr - rng

        with pytest.raises(TypeError):
            tdi - rng

    # -----------------------------------------------------------------
    # operations with array/Index of DateOffset objects

    @pytest.mark.parametrize('box', [np.array, pd.Index])
    def test_pi_add_offset_array(self, box):
        # GH#18849
        pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('2016Q2')])
        offs = box([pd.offsets.QuarterEnd(n=1, startingMonth=12),
                    pd.offsets.QuarterEnd(n=-2, startingMonth=12)])
        expected = pd.PeriodIndex([pd.Period('2015Q2'), pd.Period('2015Q4')])

        with tm.assert_produces_warning(PerformanceWarning):
            res = pi + offs
        tm.assert_index_equal(res, expected)

        with tm.assert_produces_warning(PerformanceWarning):
            res2 = offs + pi
        tm.assert_index_equal(res2, expected)

        unanchored = np.array([pd.offsets.Hour(n=1),
                               pd.offsets.Minute(n=-2)])
        # addition/subtraction ops with incompatible offsets should issue
        # a PerformanceWarning and _then_ raise a TypeError.
        with pytest.raises(IncompatibleFrequency):
            with tm.assert_produces_warning(PerformanceWarning):
                pi + unanchored
        with pytest.raises(IncompatibleFrequency):
            with tm.assert_produces_warning(PerformanceWarning):
                unanchored + pi

    @pytest.mark.parametrize('box', [np.array, pd.Index])
    def test_pi_sub_offset_array(self, box):
        # GH#18824
        pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('2016Q2')])
        other = box([pd.offsets.QuarterEnd(n=1, startingMonth=12),
                     pd.offsets.QuarterEnd(n=-2, startingMonth=12)])

        expected = PeriodIndex([pi[n] - other[n] for n in range(len(pi))])

        with tm.assert_produces_warning(PerformanceWarning):
            res = pi - other
        tm.assert_index_equal(res, expected)

        anchored = box([pd.offsets.MonthEnd(), pd.offsets.Day(n=2)])

        # addition/subtraction ops with anchored offsets should issue
        # a PerformanceWarning and _then_ raise a TypeError.
        with pytest.raises(IncompatibleFrequency):
            with tm.assert_produces_warning(PerformanceWarning):
                pi - anchored
        with pytest.raises(IncompatibleFrequency):
            with tm.assert_produces_warning(PerformanceWarning):
                anchored - pi

    def test_pi_add_iadd_int(self, one):
        # Variants of `one` for #19012
        rng = pd.period_range('2000-01-01 09:00', freq='H', periods=10)
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            result = rng + one
        expected = pd.period_range('2000-01-01 10:00', freq='H', periods=10)
        tm.assert_index_equal(result, expected)
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            rng += one
        tm.assert_index_equal(rng, expected)

    def test_pi_sub_isub_int(self, one):
        """
        PeriodIndex.__sub__ and __isub__ with several representations of
        the integer 1, e.g. int, long, np.int64, np.uint8, ...
        """
        rng = pd.period_range('2000-01-01 09:00', freq='H', periods=10)
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            result = rng - one
        expected = pd.period_range('2000-01-01 08:00', freq='H', periods=10)
        tm.assert_index_equal(result, expected)
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            rng -= one
        tm.assert_index_equal(rng, expected)

    @pytest.mark.parametrize('five', [5, np.array(5, dtype=np.int64)])
    def test_pi_sub_intlike(self, five):
        rng = period_range('2007-01', periods=50)

        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            result = rng - five
            exp = rng + (-five)
        tm.assert_index_equal(result, exp)

    def test_pi_sub_isub_offset(self):
        # offset
        # DateOffset
        rng = pd.period_range('2014', '2024', freq='A')
        result = rng - pd.offsets.YearEnd(5)
        expected = pd.period_range('2009', '2019', freq='A')
        tm.assert_index_equal(result, expected)
        rng -= pd.offsets.YearEnd(5)
        tm.assert_index_equal(rng, expected)

        rng = pd.period_range('2014-01', '2016-12', freq='M')
        result = rng - pd.offsets.MonthEnd(5)
        expected = pd.period_range('2013-08', '2016-07', freq='M')
        tm.assert_index_equal(result, expected)

        rng -= pd.offsets.MonthEnd(5)
        tm.assert_index_equal(rng, expected)

    def test_pi_add_offset_n_gt1(self, box_transpose_fail):
        # GH#23215
        # add offset to PeriodIndex with freq.n > 1
        box, transpose = box_transpose_fail

        per = pd.Period('2016-01', freq='2M')
        pi = pd.PeriodIndex([per])

        expected = pd.PeriodIndex(['2016-03'], freq='2M')

        pi = tm.box_expected(pi, box, transpose=transpose)
        expected = tm.box_expected(expected, box, transpose=transpose)

        result = pi + per.freq
        tm.assert_equal(result, expected)

        result = per.freq + pi
        tm.assert_equal(result, expected)

    def test_pi_add_offset_n_gt1_not_divisible(self, box_with_array):
        # GH#23215
        # PeriodIndex with freq.n > 1 add offset with offset.n % freq.n != 0
        pi = pd.PeriodIndex(['2016-01'], freq='2M')
        expected = pd.PeriodIndex(['2016-04'], freq='2M')

        # FIXME: with transposing these tests fail
        pi = tm.box_expected(pi, box_with_array, transpose=False)
        expected = tm.box_expected(expected, box_with_array, transpose=False)

        result = pi + to_offset('3M')
        tm.assert_equal(result, expected)

        # This test is broken
        # result = to_offset('3M') + pi
        # tm.assert_equal(result, expected)

    # ---------------------------------------------------------------
    # __add__/__sub__ with integer arrays

    @pytest.mark.parametrize('int_holder', [np.array, pd.Index])
    @pytest.mark.parametrize('op', [operator.add, ops.radd])
    def test_pi_add_intarray(self, int_holder, op):
        # GH#19959
        pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('NaT')])
        other = int_holder([4, -1])
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            result = op(pi, other)
        expected = pd.PeriodIndex([pd.Period('2016Q1'), pd.Period('NaT')])
        tm.assert_index_equal(result, expected)

    @pytest.mark.parametrize('int_holder', [np.array, pd.Index])
    def test_pi_sub_intarray(self, int_holder):
        # GH#19959
        pi = pd.PeriodIndex([pd.Period('2015Q1'), pd.Period('NaT')])
        other = int_holder([4, -1])
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            result = pi - other
        expected = pd.PeriodIndex([pd.Period('2014Q1'), pd.Period('NaT')])
        tm.assert_index_equal(result, expected)

        with pytest.raises(TypeError):
            with tm.assert_produces_warning(FutureWarning,
                                            check_stacklevel=False):
                other - pi

    # ---------------------------------------------------------------
    # Timedelta-like (timedelta, timedelta64, Timedelta, Tick)
    # TODO: Some of these are misnomers because of non-Tick DateOffsets

    def test_pi_add_timedeltalike_minute_gt1(self, three_days):
        # GH#23031 adding a time-delta-like offset to a PeriodArray that has
        # minute frequency with n != 1.  A more general case is tested below
        # in test_pi_add_timedeltalike_tick_gt1, but here we write out the
        # expected result more explicitly.
        other = three_days
        rng = pd.period_range('2014-05-01', periods=3, freq='2D')

        expected = pd.PeriodIndex(['2014-05-04', '2014-05-06', '2014-05-08'],
                                  freq='2D')

        result = rng + other
        tm.assert_index_equal(result, expected)

        result = other + rng
        tm.assert_index_equal(result, expected)

        # subtraction
        expected = pd.PeriodIndex(['2014-04-28', '2014-04-30', '2014-05-02'],
                                  freq='2D')
        result = rng - other
        tm.assert_index_equal(result, expected)

        with pytest.raises(TypeError):
            other - rng

    @pytest.mark.parametrize('freqstr', ['5ns', '5us', '5ms',
                                         '5s', '5T', '5h', '5d'])
    def test_pi_add_timedeltalike_tick_gt1(self, three_days, freqstr):
        # GH#23031 adding a time-delta-like offset to a PeriodArray that has
        # tick-like frequency with n != 1
        other = three_days
        rng = pd.period_range('2014-05-01', periods=6, freq=freqstr)

        expected = pd.period_range(rng[0] + other, periods=6, freq=freqstr)

        result = rng + other
        tm.assert_index_equal(result, expected)

        result = other + rng
        tm.assert_index_equal(result, expected)

        # subtraction
        expected = pd.period_range(rng[0] - other, periods=6, freq=freqstr)
        result = rng - other
        tm.assert_index_equal(result, expected)

        with pytest.raises(TypeError):
            other - rng

    def test_pi_add_iadd_timedeltalike_daily(self, three_days):
        # Tick
        other = three_days
        rng = pd.period_range('2014-05-01', '2014-05-15', freq='D')
        expected = pd.period_range('2014-05-04', '2014-05-18', freq='D')

        result = rng + other
        tm.assert_index_equal(result, expected)

        rng += other
        tm.assert_index_equal(rng, expected)

    def test_pi_sub_isub_timedeltalike_daily(self, three_days):
        # Tick-like 3 Days
        other = three_days
        rng = pd.period_range('2014-05-01', '2014-05-15', freq='D')
        expected = pd.period_range('2014-04-28', '2014-05-12', freq='D')

        result = rng - other
        tm.assert_index_equal(result, expected)

        rng -= other
        tm.assert_index_equal(rng, expected)

    def test_pi_add_sub_timedeltalike_freq_mismatch_daily(self, not_daily):
        other = not_daily
        rng = pd.period_range('2014-05-01', '2014-05-15', freq='D')
        msg = 'Input has different freq(=.+)? from Period.*?\\(freq=D\\)'
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng + other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng += other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng - other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng -= other

    def test_pi_add_iadd_timedeltalike_hourly(self, two_hours):
        other = two_hours
        rng = pd.period_range('2014-01-01 10:00', '2014-01-05 10:00', freq='H')
        expected = pd.period_range('2014-01-01 12:00', '2014-01-05 12:00',
                                   freq='H')

        result = rng + other
        tm.assert_index_equal(result, expected)

        rng += other
        tm.assert_index_equal(rng, expected)

    def test_pi_add_timedeltalike_mismatched_freq_hourly(self, not_hourly):
        other = not_hourly
        rng = pd.period_range('2014-01-01 10:00', '2014-01-05 10:00', freq='H')
        msg = 'Input has different freq(=.+)? from Period.*?\\(freq=H\\)'

        with pytest.raises(IncompatibleFrequency, match=msg):
            rng + other

        with pytest.raises(IncompatibleFrequency, match=msg):
            rng += other

    def test_pi_sub_isub_timedeltalike_hourly(self, two_hours):
        other = two_hours
        rng = pd.period_range('2014-01-01 10:00', '2014-01-05 10:00', freq='H')
        expected = pd.period_range('2014-01-01 08:00', '2014-01-05 08:00',
                                   freq='H')

        result = rng - other
        tm.assert_index_equal(result, expected)

        rng -= other
        tm.assert_index_equal(rng, expected)

    def test_add_iadd_timedeltalike_annual(self):
        # offset
        # DateOffset
        rng = pd.period_range('2014', '2024', freq='A')
        result = rng + pd.offsets.YearEnd(5)
        expected = pd.period_range('2019', '2029', freq='A')
        tm.assert_index_equal(result, expected)
        rng += pd.offsets.YearEnd(5)
        tm.assert_index_equal(rng, expected)

    def test_pi_add_sub_timedeltalike_freq_mismatch_annual(self,
                                                           mismatched_freq):
        other = mismatched_freq
        rng = pd.period_range('2014', '2024', freq='A')
        msg = ('Input has different freq(=.+)? '
               'from Period.*?\\(freq=A-DEC\\)')
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng + other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng += other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng - other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng -= other

    def test_pi_add_iadd_timedeltalike_M(self):
        rng = pd.period_range('2014-01', '2016-12', freq='M')
        expected = pd.period_range('2014-06', '2017-05', freq='M')

        result = rng + pd.offsets.MonthEnd(5)
        tm.assert_index_equal(result, expected)

        rng += pd.offsets.MonthEnd(5)
        tm.assert_index_equal(rng, expected)

    def test_pi_add_sub_timedeltalike_freq_mismatch_monthly(self,
                                                            mismatched_freq):
        other = mismatched_freq
        rng = pd.period_range('2014-01', '2016-12', freq='M')
        msg = 'Input has different freq(=.+)? from Period.*?\\(freq=M\\)'
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng + other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng += other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng - other
        with pytest.raises(IncompatibleFrequency, match=msg):
            rng -= other

    def test_parr_add_sub_td64_nat(self, box_transpose_fail):
        # GH#23320 special handling for timedelta64("NaT")
        box, transpose = box_transpose_fail

        pi = pd.period_range("1994-04-01", periods=9, freq="19D")
        other = np.timedelta64("NaT")
        expected = pd.PeriodIndex(["NaT"] * 9, freq="19D")

        obj = tm.box_expected(pi, box, transpose=transpose)
        expected = tm.box_expected(expected, box, transpose=transpose)

        result = obj + other
        tm.assert_equal(result, expected)
        result = other + obj
        tm.assert_equal(result, expected)
        result = obj - other
        tm.assert_equal(result, expected)
        with pytest.raises(TypeError):
            other - obj


class TestPeriodSeriesArithmetic(object):
    def test_ops_series_timedelta(self):
        # GH#13043
        ser = pd.Series([pd.Period('2015-01-01', freq='D'),
                         pd.Period('2015-01-02', freq='D')], name='xxx')
        assert ser.dtype == 'Period[D]'

        expected = pd.Series([pd.Period('2015-01-02', freq='D'),
                              pd.Period('2015-01-03', freq='D')], name='xxx')

        result = ser + pd.Timedelta('1 days')
        tm.assert_series_equal(result, expected)

        result = pd.Timedelta('1 days') + ser
        tm.assert_series_equal(result, expected)

        result = ser + pd.tseries.offsets.Day()
        tm.assert_series_equal(result, expected)

        result = pd.tseries.offsets.Day() + ser
        tm.assert_series_equal(result, expected)

    def test_ops_series_period(self):
        # GH#13043
        ser = pd.Series([pd.Period('2015-01-01', freq='D'),
                         pd.Period('2015-01-02', freq='D')], name='xxx')
        assert ser.dtype == "Period[D]"

        per = pd.Period('2015-01-10', freq='D')
        off = per.freq
        # dtype will be object because of original dtype
        expected = pd.Series([9 * off, 8 * off], name='xxx', dtype=object)
        tm.assert_series_equal(per - ser, expected)
        tm.assert_series_equal(ser - per, -1 * expected)

        s2 = pd.Series([pd.Period('2015-01-05', freq='D'),
                        pd.Period('2015-01-04', freq='D')], name='xxx')
        assert s2.dtype == "Period[D]"

        expected = pd.Series([4 * off, 2 * off], name='xxx', dtype=object)
        tm.assert_series_equal(s2 - ser, expected)
        tm.assert_series_equal(ser - s2, -1 * expected)


class TestPeriodIndexSeriesMethods(object):
    """ Test PeriodIndex and Period Series Ops consistency """

    def _check(self, values, func, expected):
        idx = pd.PeriodIndex(values)
        result = func(idx)
        tm.assert_equal(result, expected)

        ser = pd.Series(values)
        result = func(ser)

        exp = pd.Series(expected, name=values.name)
        tm.assert_series_equal(result, exp)

    def test_pi_ops(self):
        idx = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                          freq='M', name='idx')

        expected = PeriodIndex(['2011-03', '2011-04', '2011-05', '2011-06'],
                               freq='M', name='idx')
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            self._check(idx, lambda x: x + 2, expected)
            self._check(idx, lambda x: 2 + x, expected)

            self._check(idx + 2, lambda x: x - 2, idx)

        result = idx - Period('2011-01', freq='M')
        off = idx.freq
        exp = pd.Index([0 * off, 1 * off, 2 * off, 3 * off], name='idx')
        tm.assert_index_equal(result, exp)

        result = Period('2011-01', freq='M') - idx
        exp = pd.Index([0 * off, -1 * off, -2 * off, -3 * off], name='idx')
        tm.assert_index_equal(result, exp)

    @pytest.mark.parametrize('ng', ["str", 1.5])
    def test_parr_ops_errors(self, ng, box_with_array):
        idx = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                          freq='M', name='idx')
        obj = tm.box_expected(idx, box_with_array)

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

        with pytest.raises(TypeError):
            # error message differs between PY2 and 3
            ng + obj

        with pytest.raises(TypeError, match=msg):
            obj - ng

        with pytest.raises(TypeError):
            np.add(obj, ng)

        with pytest.raises(TypeError):
            np.add(ng, obj)

        with pytest.raises(TypeError):
            np.subtract(obj, ng)

        with pytest.raises(TypeError):
            np.subtract(ng, obj)

    def test_pi_ops_nat(self):
        idx = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-04'],
                          freq='M', name='idx')
        expected = PeriodIndex(['2011-03', '2011-04', 'NaT', '2011-06'],
                               freq='M', name='idx')
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            self._check(idx, lambda x: x + 2, expected)
            self._check(idx, lambda x: 2 + x, expected)
            self._check(idx, lambda x: np.add(x, 2), expected)

            self._check(idx + 2, lambda x: x - 2, idx)
            self._check(idx + 2, lambda x: np.subtract(x, 2), idx)

        # freq with mult
        idx = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-04'],
                          freq='2M', name='idx')
        expected = PeriodIndex(['2011-07', '2011-08', 'NaT', '2011-10'],
                               freq='2M', name='idx')
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            self._check(idx, lambda x: x + 3, expected)
            self._check(idx, lambda x: 3 + x, expected)
            self._check(idx, lambda x: np.add(x, 3), expected)

            self._check(idx + 3, lambda x: x - 3, idx)
            self._check(idx + 3, lambda x: np.subtract(x, 3), idx)

    def test_pi_ops_array_int(self):
        with tm.assert_produces_warning(FutureWarning, check_stacklevel=False,
                                        clear=[pd.core.arrays.datetimelike]):
            idx = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-04'],
                              freq='M', name='idx')
            f = lambda x: x + np.array([1, 2, 3, 4])
            exp = PeriodIndex(['2011-02', '2011-04', 'NaT', '2011-08'],
                              freq='M', name='idx')
            self._check(idx, f, exp)

            f = lambda x: np.add(x, np.array([4, -1, 1, 2]))
            exp = PeriodIndex(['2011-05', '2011-01', 'NaT', '2011-06'],
                              freq='M', name='idx')
            self._check(idx, f, exp)

            f = lambda x: x - np.array([1, 2, 3, 4])
            exp = PeriodIndex(['2010-12', '2010-12', 'NaT', '2010-12'],
                              freq='M', name='idx')
            self._check(idx, f, exp)

            f = lambda x: np.subtract(x, np.array([3, 2, 3, -2]))
            exp = PeriodIndex(['2010-10', '2010-12', 'NaT', '2011-06'],
                              freq='M', name='idx')
            self._check(idx, f, exp)

    def test_pi_ops_offset(self):
        idx = PeriodIndex(['2011-01-01', '2011-02-01', '2011-03-01',
                           '2011-04-01'], freq='D', name='idx')
        f = lambda x: x + pd.offsets.Day()
        exp = PeriodIndex(['2011-01-02', '2011-02-02', '2011-03-02',
                           '2011-04-02'], freq='D', name='idx')
        self._check(idx, f, exp)

        f = lambda x: x + pd.offsets.Day(2)
        exp = PeriodIndex(['2011-01-03', '2011-02-03', '2011-03-03',
                           '2011-04-03'], freq='D', name='idx')
        self._check(idx, f, exp)

        f = lambda x: x - pd.offsets.Day(2)
        exp = PeriodIndex(['2010-12-30', '2011-01-30', '2011-02-27',
                           '2011-03-30'], freq='D', name='idx')
        self._check(idx, f, exp)

    def test_pi_offset_errors(self):
        idx = PeriodIndex(['2011-01-01', '2011-02-01', '2011-03-01',
                           '2011-04-01'], freq='D', name='idx')
        ser = pd.Series(idx)

        # Series op is applied per Period instance, thus error is raised
        # from Period
        msg = r"Input has different freq from Period.*?\(freq=D\)"
        for obj in [idx, ser]:
            with pytest.raises(IncompatibleFrequency, match=msg):
                obj + pd.offsets.Hour(2)

            with pytest.raises(IncompatibleFrequency, match=msg):
                pd.offsets.Hour(2) + obj

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

    def test_pi_sub_period(self):
        # GH#13071
        idx = PeriodIndex(['2011-01', '2011-02', '2011-03', '2011-04'],
                          freq='M', name='idx')

        result = idx - pd.Period('2012-01', freq='M')
        off = idx.freq
        exp = pd.Index([-12 * off, -11 * off, -10 * off, -9 * off], name='idx')
        tm.assert_index_equal(result, exp)

        result = np.subtract(idx, pd.Period('2012-01', freq='M'))
        tm.assert_index_equal(result, exp)

        result = pd.Period('2012-01', freq='M') - idx
        exp = pd.Index([12 * off, 11 * off, 10 * off, 9 * off], name='idx')
        tm.assert_index_equal(result, exp)

        result = np.subtract(pd.Period('2012-01', freq='M'), idx)
        tm.assert_index_equal(result, exp)

        exp = pd.TimedeltaIndex([np.nan, np.nan, np.nan, np.nan], name='idx')
        tm.assert_index_equal(idx - pd.Period('NaT', freq='M'), exp)
        tm.assert_index_equal(pd.Period('NaT', freq='M') - idx, exp)

    def test_pi_sub_pdnat(self):
        # GH#13071
        idx = PeriodIndex(['2011-01', '2011-02', 'NaT', '2011-04'],
                          freq='M', name='idx')
        exp = pd.TimedeltaIndex([pd.NaT] * 4, name='idx')
        tm.assert_index_equal(pd.NaT - idx, exp)
        tm.assert_index_equal(idx - pd.NaT, exp)

    def test_pi_sub_period_nat(self):
        # GH#13071
        idx = PeriodIndex(['2011-01', 'NaT', '2011-03', '2011-04'],
                          freq='M', name='idx')

        result = idx - pd.Period('2012-01', freq='M')
        off = idx.freq
        exp = pd.Index([-12 * off, pd.NaT, -10 * off, -9 * off], name='idx')
        tm.assert_index_equal(result, exp)

        result = pd.Period('2012-01', freq='M') - idx
        exp = pd.Index([12 * off, pd.NaT, 10 * off, 9 * off], name='idx')
        tm.assert_index_equal(result, exp)

        exp = pd.TimedeltaIndex([np.nan, np.nan, np.nan, np.nan], name='idx')
        tm.assert_index_equal(idx - pd.Period('NaT', freq='M'), exp)
        tm.assert_index_equal(pd.Period('NaT', freq='M') - idx, exp)


class TestPeriodArithmetic(object):

    @pytest.mark.parametrize('freq,expected', [
        (pd.offsets.Second, 18489600),
        (pd.offsets.Minute, 308160),
        (pd.offsets.Hour, 5136),
        (pd.offsets.Day, 214),
        (pd.offsets.MonthEnd, 7),
        (pd.offsets.YearEnd, 1),
    ])
    def test_period_diff(self, freq, expected):
        # GH 23878
        for i in range(1, 4):
            p1 = pd.Period('19910905', freq=freq(i))
            p2 = pd.Period('19920406', freq=freq(i))
            assert (p2 - p1) == freq(expected)