Separate out arithmetic tests for datetimelike indexes (pandas-dev#18049)

Author: jbrockmendel

pandas/tests/indexes/datetimes/test_arithmetic.py

@@ -0,0 +1,335 @@
+# -*- coding: utf-8 -*-
+import warnings
+from datetime import datetime, timedelta
+
+import pytest
+
+import numpy as np
+
+import pandas as pd
+import pandas.util.testing as tm
+from pandas.errors import PerformanceWarning
+from pandas import (Timestamp, Timedelta, Series,
+                    DatetimeIndex, TimedeltaIndex,
+                    date_range)
+
+
+class TestDatetimeIndexArithmetic(object):
+    tz = [None, 'UTC', 'Asia/Tokyo', 'US/Eastern', 'dateutil/Asia/Singapore',
+          'dateutil/US/Pacific']
+
+    def test_add_iadd(self):
+        for tz in self.tz:
+
+            # offset
+            offsets = [pd.offsets.Hour(2), timedelta(hours=2),
+                       np.timedelta64(2, 'h'), Timedelta(hours=2)]
+
+            for delta in offsets:
+                rng = pd.date_range('2000-01-01', '2000-02-01', tz=tz)
+                result = rng + delta
+                expected = pd.date_range('2000-01-01 02:00',
+                                         '2000-02-01 02:00', tz=tz)
+                tm.assert_index_equal(result, expected)
+                rng += delta
+                tm.assert_index_equal(rng, expected)
+
+            # int
+            rng = pd.date_range('2000-01-01 09:00', freq='H', periods=10,
+                                tz=tz)
+            result = rng + 1
+            expected = pd.date_range('2000-01-01 10:00', freq='H', periods=10,
+                                     tz=tz)
+            tm.assert_index_equal(result, expected)
+            rng += 1
+            tm.assert_index_equal(rng, expected)
+
+        idx = DatetimeIndex(['2011-01-01', '2011-01-02'])
+        msg = "cannot add DatetimeIndex and Timestamp"
+        with tm.assert_raises_regex(TypeError, msg):
+            idx + Timestamp('2011-01-01')
+
+        with tm.assert_raises_regex(TypeError, msg):
+            Timestamp('2011-01-01') + idx
+
+    def test_sub_isub(self):
+        for tz in self.tz:
+
+            # offset
+            offsets = [pd.offsets.Hour(2), timedelta(hours=2),
+                       np.timedelta64(2, 'h'), Timedelta(hours=2)]
+
+            for delta in offsets:
+                rng = pd.date_range('2000-01-01', '2000-02-01', tz=tz)
+                expected = pd.date_range('1999-12-31 22:00',
+                                         '2000-01-31 22:00', tz=tz)
+
+                result = rng - delta
+                tm.assert_index_equal(result, expected)
+                rng -= delta
+                tm.assert_index_equal(rng, expected)
+
+            # int
+            rng = pd.date_range('2000-01-01 09:00', freq='H', periods=10,
+                                tz=tz)
+            result = rng - 1
+            expected = pd.date_range('2000-01-01 08:00', freq='H', periods=10,
+                                     tz=tz)
+            tm.assert_index_equal(result, expected)
+            rng -= 1
+            tm.assert_index_equal(rng, expected)
+
+    @pytest.mark.parametrize('addend', [
+        datetime(2011, 1, 1),
+        DatetimeIndex(['2011-01-01', '2011-01-02']),
+        DatetimeIndex(['2011-01-01', '2011-01-02']).tz_localize('US/Eastern'),
+        np.datetime64('2011-01-01'),
+        Timestamp('2011-01-01')])
+    def test_add_datetimelike_and_dti(self, addend):
+        # GH#9631
+        dti = DatetimeIndex(['2011-01-01', '2011-01-02'])
+        msg = 'cannot add DatetimeIndex and {0}'.format(
+            type(addend).__name__)
+        with tm.assert_raises_regex(TypeError, msg):
+            dti + addend
+        with tm.assert_raises_regex(TypeError, msg):
+            addend + dti
+
+    @pytest.mark.parametrize('addend', [
+        datetime(2011, 1, 1),
+        DatetimeIndex(['2011-01-01', '2011-01-02']),
+        DatetimeIndex(['2011-01-01', '2011-01-02']).tz_localize('US/Eastern'),
+        np.datetime64('2011-01-01'),
+        Timestamp('2011-01-01')])
+    def test_add_datetimelike_and_dti_tz(self, addend):
+        # GH#9631
+        dti_tz = DatetimeIndex(['2011-01-01',
+                                '2011-01-02']).tz_localize('US/Eastern')
+        msg = 'cannot add DatetimeIndex and {0}'.format(
+            type(addend).__name__)
+        with tm.assert_raises_regex(TypeError, msg):
+            dti_tz + addend
+        with tm.assert_raises_regex(TypeError, msg):
+            addend + dti_tz
+
+    def test_sub_dti_dti(self):
+        # previously performed setop (deprecated in 0.16.0), now changed to
+        # return subtraction -> TimeDeltaIndex (GH ...)
+
+        dti = date_range('20130101', periods=3)
+        dti_tz = date_range('20130101', periods=3).tz_localize('US/Eastern')
+        dti_tz2 = date_range('20130101', periods=3).tz_localize('UTC')
+        expected = TimedeltaIndex([0, 0, 0])
+
+        result = dti - dti
+        tm.assert_index_equal(result, expected)
+
+        result = dti_tz - dti_tz
+        tm.assert_index_equal(result, expected)
+
+        with pytest.raises(TypeError):
+            dti_tz - dti
+
+        with pytest.raises(TypeError):
+            dti - dti_tz
+
+        with pytest.raises(TypeError):
+            dti_tz - dti_tz2
+
+        # isub
+        dti -= dti
+        tm.assert_index_equal(dti, expected)
+
+        # different length raises ValueError
+        dti1 = date_range('20130101', periods=3)
+        dti2 = date_range('20130101', periods=4)
+        with pytest.raises(ValueError):
+            dti1 - dti2
+
+        # NaN propagation
+        dti1 = DatetimeIndex(['2012-01-01', np.nan, '2012-01-03'])
+        dti2 = DatetimeIndex(['2012-01-02', '2012-01-03', np.nan])
+        expected = TimedeltaIndex(['1 days', np.nan, np.nan])
+        result = dti2 - dti1
+        tm.assert_index_equal(result, expected)
+
+    def test_sub_period(self):
+        # GH 13078
+        # not supported, check TypeError
+        p = pd.Period('2011-01-01', freq='D')
+
+        for freq in [None, 'D']:
+            idx = pd.DatetimeIndex(['2011-01-01', '2011-01-02'], freq=freq)
+
+            with pytest.raises(TypeError):
+                idx - p
+
+            with pytest.raises(TypeError):
+                p - idx
+
+    def test_ufunc_coercions(self):
+        idx = date_range('2011-01-01', periods=3, freq='2D', name='x')
+
+        delta = np.timedelta64(1, 'D')
+        for result in [idx + delta, np.add(idx, delta)]:
+            assert isinstance(result, DatetimeIndex)
+            exp = date_range('2011-01-02', periods=3, freq='2D', name='x')
+            tm.assert_index_equal(result, exp)
+            assert result.freq == '2D'
+
+        for result in [idx - delta, np.subtract(idx, delta)]:
+            assert isinstance(result, DatetimeIndex)
+            exp = date_range('2010-12-31', periods=3, freq='2D', name='x')
+            tm.assert_index_equal(result, exp)
+            assert result.freq == '2D'
+
+        delta = np.array([np.timedelta64(1, 'D'), np.timedelta64(2, 'D'),
+                          np.timedelta64(3, 'D')])
+        for result in [idx + delta, np.add(idx, delta)]:
+            assert isinstance(result, DatetimeIndex)
+            exp = DatetimeIndex(['2011-01-02', '2011-01-05', '2011-01-08'],
+                                freq='3D', name='x')
+            tm.assert_index_equal(result, exp)
+            assert result.freq == '3D'
+
+        for result in [idx - delta, np.subtract(idx, delta)]:
+            assert isinstance(result, DatetimeIndex)
+            exp = DatetimeIndex(['2010-12-31', '2011-01-01', '2011-01-02'],
+                                freq='D', name='x')
+            tm.assert_index_equal(result, exp)
+            assert result.freq == 'D'
+
+    def test_overflow_offset(self):
+        # xref https://github.com/statsmodels/statsmodels/issues/3374
+        # ends up multiplying really large numbers which overflow
+
+        t = Timestamp('2017-01-13 00:00:00', freq='D')
+        offset = 20169940 * pd.offsets.Day(1)
+
+        def f():
+            t + offset
+        pytest.raises(OverflowError, f)
+
+        def f():
+            offset + t
+        pytest.raises(OverflowError, f)
+
+        def f():
+            t - offset
+        pytest.raises(OverflowError, f)
+
+
+# GH 10699
+@pytest.mark.parametrize('klass,assert_func', zip([Series, DatetimeIndex],
+                                                  [tm.assert_series_equal,
+                                                   tm.assert_index_equal]))
+def test_datetime64_with_DateOffset(klass, assert_func):
+    s = klass(date_range('2000-01-01', '2000-01-31'), name='a')
+    result = s + pd.DateOffset(years=1)
+    result2 = pd.DateOffset(years=1) + s
+    exp = klass(date_range('2001-01-01', '2001-01-31'), name='a')
+    assert_func(result, exp)
+    assert_func(result2, exp)
+
+    result = s - pd.DateOffset(years=1)
+    exp = klass(date_range('1999-01-01', '1999-01-31'), name='a')
+    assert_func(result, exp)
+
+    s = klass([Timestamp('2000-01-15 00:15:00', tz='US/Central'),
+               pd.Timestamp('2000-02-15', tz='US/Central')], name='a')
+    result = s + pd.offsets.Day()
+    result2 = pd.offsets.Day() + s
+    exp = klass([Timestamp('2000-01-16 00:15:00', tz='US/Central'),
+                 Timestamp('2000-02-16', tz='US/Central')], name='a')
+    assert_func(result, exp)
+    assert_func(result2, exp)
+
+    s = klass([Timestamp('2000-01-15 00:15:00', tz='US/Central'),
+               pd.Timestamp('2000-02-15', tz='US/Central')], name='a')
+    result = s + pd.offsets.MonthEnd()
+    result2 = pd.offsets.MonthEnd() + s
+    exp = klass([Timestamp('2000-01-31 00:15:00', tz='US/Central'),
+                 Timestamp('2000-02-29', tz='US/Central')], name='a')
+    assert_func(result, exp)
+    assert_func(result2, exp)
+
+    # array of offsets - valid for Series only
+    if klass is Series:
+        with tm.assert_produces_warning(PerformanceWarning):
+            s = klass([Timestamp('2000-1-1'), Timestamp('2000-2-1')])
+            result = s + Series([pd.offsets.DateOffset(years=1),
+                                 pd.offsets.MonthEnd()])
+            exp = klass([Timestamp('2001-1-1'), Timestamp('2000-2-29')
+                         ])
+            assert_func(result, exp)
+
+            # same offset
+            result = s + Series([pd.offsets.DateOffset(years=1),
+                                 pd.offsets.DateOffset(years=1)])
+            exp = klass([Timestamp('2001-1-1'), Timestamp('2001-2-1')])
+            assert_func(result, exp)
+
+    s = klass([Timestamp('2000-01-05 00:15:00'),
+               Timestamp('2000-01-31 00:23:00'),
+               Timestamp('2000-01-01'),
+               Timestamp('2000-03-31'),
+               Timestamp('2000-02-29'),
+               Timestamp('2000-12-31'),
+               Timestamp('2000-05-15'),
+               Timestamp('2001-06-15')])
+
+    # DateOffset relativedelta fastpath
+    relative_kwargs = [('years', 2), ('months', 5), ('days', 3),
+                       ('hours', 5), ('minutes', 10), ('seconds', 2),
+                       ('microseconds', 5)]
+    for i, kwd in enumerate(relative_kwargs):
+        op = pd.DateOffset(**dict([kwd]))
+        assert_func(klass([x + op for x in s]), s + op)
+        assert_func(klass([x - op for x in s]), s - op)
+        op = pd.DateOffset(**dict(relative_kwargs[:i + 1]))
+        assert_func(klass([x + op for x in s]), s + op)
+        assert_func(klass([x - op for x in s]), s - op)
+
+    # assert these are equal on a piecewise basis
+    offsets = ['YearBegin', ('YearBegin', {'month': 5}),
+               'YearEnd', ('YearEnd', {'month': 5}),
+               'MonthBegin', 'MonthEnd',
+               'SemiMonthEnd', 'SemiMonthBegin',
+               'Week', ('Week', {'weekday': 3}),
+               'BusinessDay', 'BDay', 'QuarterEnd', 'QuarterBegin',
+               'CustomBusinessDay', 'CDay', 'CBMonthEnd',
+               'CBMonthBegin', 'BMonthBegin', 'BMonthEnd',
+               'BusinessHour', 'BYearBegin', 'BYearEnd',
+               'BQuarterBegin', ('LastWeekOfMonth', {'weekday': 2}),
+               ('FY5253Quarter', {'qtr_with_extra_week': 1,
+                                  'startingMonth': 1,
+                                  'weekday': 2,
+                                  'variation': 'nearest'}),
+               ('FY5253', {'weekday': 0,
+                           'startingMonth': 2,
+                           'variation':
+                           'nearest'}),
+               ('WeekOfMonth', {'weekday': 2,
+                                'week': 2}),
+               'Easter', ('DateOffset', {'day': 4}),
+               ('DateOffset', {'month': 5})]
+
+    with warnings.catch_warnings(record=True):
+        for normalize in (True, False):
+            for do in offsets:
+                if isinstance(do, tuple):
+                    do, kwargs = do
+                else:
+                    do = do
+                    kwargs = {}
+
+                    for n in [0, 5]:
+                        if (do in ['WeekOfMonth', 'LastWeekOfMonth',
+                                   'FY5253Quarter', 'FY5253'] and n == 0):
+                            continue
+                    op = getattr(pd.offsets, do)(n,
+                                                 normalize=normalize,
+                                                 **kwargs)
+                    assert_func(klass([x + op for x in s]), s + op)
+                    assert_func(klass([x - op for x in s]), s - op)
+                    assert_func(klass([op + x for x in s]), op + s)