ai-content-maker/.venv/Lib/site-packages/pandas/tests/tseries/offsets/test_dst.py

231 lines
7.7 KiB
Python

"""
Tests for DateOffset additions over Daylight Savings Time
"""
from datetime import timedelta
import pytest
import pytz
from pandas._libs.tslibs import Timestamp
from pandas._libs.tslibs.offsets import (
BMonthBegin,
BMonthEnd,
BQuarterBegin,
BQuarterEnd,
BYearBegin,
BYearEnd,
CBMonthBegin,
CBMonthEnd,
CustomBusinessDay,
DateOffset,
Day,
MonthBegin,
MonthEnd,
QuarterBegin,
QuarterEnd,
SemiMonthBegin,
SemiMonthEnd,
Week,
YearBegin,
YearEnd,
)
from pandas.tests.tseries.offsets.test_offsets import get_utc_offset_hours
from pandas.util.version import Version
# error: Module has no attribute "__version__"
pytz_version = Version(pytz.__version__) # type: ignore[attr-defined]
class TestDST:
# one microsecond before the DST transition
ts_pre_fallback = "2013-11-03 01:59:59.999999"
ts_pre_springfwd = "2013-03-10 01:59:59.999999"
# test both basic names and dateutil timezones
timezone_utc_offsets = {
"US/Eastern": {"utc_offset_daylight": -4, "utc_offset_standard": -5},
"dateutil/US/Pacific": {"utc_offset_daylight": -7, "utc_offset_standard": -8},
}
valid_date_offsets_singular = [
"weekday",
"day",
"hour",
"minute",
"second",
"microsecond",
]
valid_date_offsets_plural = [
"weeks",
"days",
"hours",
"minutes",
"seconds",
"milliseconds",
"microseconds",
]
def _test_all_offsets(self, n, **kwds):
valid_offsets = (
self.valid_date_offsets_plural
if n > 1
else self.valid_date_offsets_singular
)
for name in valid_offsets:
self._test_offset(offset_name=name, offset_n=n, **kwds)
def _test_offset(self, offset_name, offset_n, tstart, expected_utc_offset):
offset = DateOffset(**{offset_name: offset_n})
t = tstart + offset
if expected_utc_offset is not None:
assert get_utc_offset_hours(t) == expected_utc_offset
if offset_name == "weeks":
# dates should match
assert t.date() == timedelta(days=7 * offset.kwds["weeks"]) + tstart.date()
# expect the same day of week, hour of day, minute, second, ...
assert (
t.dayofweek == tstart.dayofweek
and t.hour == tstart.hour
and t.minute == tstart.minute
and t.second == tstart.second
)
elif offset_name == "days":
# dates should match
assert timedelta(offset.kwds["days"]) + tstart.date() == t.date()
# expect the same hour of day, minute, second, ...
assert (
t.hour == tstart.hour
and t.minute == tstart.minute
and t.second == tstart.second
)
elif offset_name in self.valid_date_offsets_singular:
# expect the singular offset value to match between tstart and t
datepart_offset = getattr(
t, offset_name if offset_name != "weekday" else "dayofweek"
)
assert datepart_offset == offset.kwds[offset_name]
else:
# the offset should be the same as if it was done in UTC
assert t == (tstart.tz_convert("UTC") + offset).tz_convert("US/Pacific")
def _make_timestamp(self, string, hrs_offset, tz):
if hrs_offset >= 0:
offset_string = f"{hrs_offset:02d}00"
else:
offset_string = f"-{(hrs_offset * -1):02}00"
return Timestamp(string + offset_string).tz_convert(tz)
def test_springforward_plural(self):
# test moving from standard to daylight savings
for tz, utc_offsets in self.timezone_utc_offsets.items():
hrs_pre = utc_offsets["utc_offset_standard"]
hrs_post = utc_offsets["utc_offset_daylight"]
self._test_all_offsets(
n=3,
tstart=self._make_timestamp(self.ts_pre_springfwd, hrs_pre, tz),
expected_utc_offset=hrs_post,
)
def test_fallback_singular(self):
# in the case of singular offsets, we don't necessarily know which utc
# offset the new Timestamp will wind up in (the tz for 1 month may be
# different from 1 second) so we don't specify an expected_utc_offset
for tz, utc_offsets in self.timezone_utc_offsets.items():
hrs_pre = utc_offsets["utc_offset_standard"]
self._test_all_offsets(
n=1,
tstart=self._make_timestamp(self.ts_pre_fallback, hrs_pre, tz),
expected_utc_offset=None,
)
def test_springforward_singular(self):
for tz, utc_offsets in self.timezone_utc_offsets.items():
hrs_pre = utc_offsets["utc_offset_standard"]
self._test_all_offsets(
n=1,
tstart=self._make_timestamp(self.ts_pre_springfwd, hrs_pre, tz),
expected_utc_offset=None,
)
offset_classes = {
MonthBegin: ["11/2/2012", "12/1/2012"],
MonthEnd: ["11/2/2012", "11/30/2012"],
BMonthBegin: ["11/2/2012", "12/3/2012"],
BMonthEnd: ["11/2/2012", "11/30/2012"],
CBMonthBegin: ["11/2/2012", "12/3/2012"],
CBMonthEnd: ["11/2/2012", "11/30/2012"],
SemiMonthBegin: ["11/2/2012", "11/15/2012"],
SemiMonthEnd: ["11/2/2012", "11/15/2012"],
Week: ["11/2/2012", "11/9/2012"],
YearBegin: ["11/2/2012", "1/1/2013"],
YearEnd: ["11/2/2012", "12/31/2012"],
BYearBegin: ["11/2/2012", "1/1/2013"],
BYearEnd: ["11/2/2012", "12/31/2012"],
QuarterBegin: ["11/2/2012", "12/1/2012"],
QuarterEnd: ["11/2/2012", "12/31/2012"],
BQuarterBegin: ["11/2/2012", "12/3/2012"],
BQuarterEnd: ["11/2/2012", "12/31/2012"],
Day: ["11/4/2012", "11/4/2012 23:00"],
}.items()
@pytest.mark.parametrize("tup", offset_classes)
def test_all_offset_classes(self, tup):
offset, test_values = tup
first = Timestamp(test_values[0], tz="US/Eastern") + offset()
second = Timestamp(test_values[1], tz="US/Eastern")
assert first == second
@pytest.mark.parametrize(
"original_dt, target_dt, offset, tz",
[
pytest.param(
Timestamp("1900-01-01"),
Timestamp("1905-07-01"),
MonthBegin(66),
"Africa/Kinshasa",
marks=pytest.mark.xfail(
pytz_version < Version("2020.5") or pytz_version == Version("2022.2"),
reason="GH#41906: pytz utc transition dates changed",
),
),
(
Timestamp("2021-10-01 01:15"),
Timestamp("2021-10-31 01:15"),
MonthEnd(1),
"Europe/London",
),
(
Timestamp("2010-12-05 02:59"),
Timestamp("2010-10-31 02:59"),
SemiMonthEnd(-3),
"Europe/Paris",
),
(
Timestamp("2021-10-31 01:20"),
Timestamp("2021-11-07 01:20"),
CustomBusinessDay(2, weekmask="Sun Mon"),
"US/Eastern",
),
(
Timestamp("2020-04-03 01:30"),
Timestamp("2020-11-01 01:30"),
YearBegin(1, month=11),
"America/Chicago",
),
],
)
def test_nontick_offset_with_ambiguous_time_error(original_dt, target_dt, offset, tz):
# .apply for non-Tick offsets throws AmbiguousTimeError when the target dt
# is dst-ambiguous
localized_dt = original_dt.tz_localize(tz)
msg = f"Cannot infer dst time from {target_dt}, try using the 'ambiguous' argument"
with pytest.raises(pytz.AmbiguousTimeError, match=msg):
localized_dt + offset