# This file is part of Hypothesis, which may be found at
# Most of this work is copyright (C) 2013-2021 David R. MacIver
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# consult the git log if you need to determine who owns an individual
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This module provides :pypi:`pytz` timezones.
You can use this strategy to make
:py:func:`hypothesis.strategies.times` produce timezone-aware values.
import datetime as dt
from pytz.tzfile import StaticTzInfo
from hypothesis import strategies as st
from hypothesis.strategies._internal.utils import cacheable, defines_strategy
__all__ = ["timezones"]
def timezones() -> st.SearchStrategy[dt.tzinfo]:
"""Any timezone in the Olsen database, as a pytz tzinfo object.
This strategy minimises to UTC, or the smallest possible fixed
offset, and is designed for use with
all_timezones = [pytz.timezone(tz) for tz in pytz.all_timezones]
# Some timezones have always had a constant offset from UTC. This makes
# them simpler than timezones with daylight savings, and the smaller the
# absolute offset the simpler they are. Of course, UTC is even simpler!
static: list = [pytz.UTC]
static += sorted(
(t for t in all_timezones if isinstance(t, StaticTzInfo)),
key=lambda tz: abs(tz.utcoffset(dt.datetime(2000, 1, 1))),
# Timezones which have changed UTC offset; best ordered by name.
dynamic = [tz for tz in all_timezones if tz not in static]
return st.sampled_from(static + dynamic)