Migrate from pytz to python-dateutil (#49643)

Co-authored-by: Paulus Schoutsen <balloob@gmail.com>

homeassistant/components/homeassistant/triggers/time.py

@@ -95,8 +95,14 @@ async def async_attach_trigger(hass, config, action, automation_info):
 
             if has_date:
                 # If input_datetime has date, then track point in time.
-                trigger_dt = dt_util.DEFAULT_TIME_ZONE.localize(
+                trigger_dt = datetime(
-                    datetime(year, month, day, hour, minute, second)
+                    year,
+                    month,
+                    day,
+                    hour,
+                    minute,
+                    second,
+                    tzinfo=dt_util.DEFAULT_TIME_ZONE,
                 )
                 # Only set up listener if time is now or in the future.
                 if trigger_dt >= dt_util.now():

homeassistant/components/hvv_departures/sensor.py

@@ -4,13 +4,12 @@ import logging
 
 from aiohttp import ClientConnectorError
 from pygti.exceptions import InvalidAuth
-from pytz import timezone
 
 from homeassistant.components.sensor import SensorEntity
 from homeassistant.const import ATTR_ATTRIBUTION, ATTR_ID, DEVICE_CLASS_TIMESTAMP
 from homeassistant.helpers import aiohttp_client
 from homeassistant.util import Throttle
-from homeassistant.util.dt import utcnow
+from homeassistant.util.dt import get_time_zone, utcnow
 
 from .const import ATTRIBUTION, CONF_STATION, DOMAIN, MANUFACTURER
 
@@ -28,6 +27,7 @@ ATTR_DELAY = "delay"
 ATTR_NEXT = "next"
 
 PARALLEL_UPDATES = 0
+BERLIN_TIME_ZONE = get_time_zone("Europe/Berlin")
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -60,12 +60,11 @@ class HVVDepartureSensor(SensorEntity):
     @Throttle(MIN_TIME_BETWEEN_UPDATES)
     async def async_update(self, **kwargs):
         """Update the sensor."""
-
         departure_time = utcnow() + timedelta(
             minutes=self.config_entry.options.get("offset", 0)
         )
 
-        departure_time_tz_berlin = departure_time.astimezone(timezone("Europe/Berlin"))
+        departure_time_tz_berlin = departure_time.astimezone(BERLIN_TIME_ZONE)
 
         payload = {
             "station": self.config_entry.data[CONF_STATION],

homeassistant/components/input_datetime/__init__.py

@@ -224,8 +224,8 @@ class InputDatetime(RestoreEntity):
                 dt_util.DEFAULT_TIME_ZONE
             )
         else:
-            self._current_datetime = dt_util.DEFAULT_TIME_ZONE.localize(
+            self._current_datetime = current_datetime.replace(
-                current_datetime
+                tzinfo=dt_util.DEFAULT_TIME_ZONE
             )
 
     @classmethod
@@ -388,8 +388,8 @@ class InputDatetime(RestoreEntity):
         if not time:
             time = self._current_datetime.time()
 
-        self._current_datetime = dt_util.DEFAULT_TIME_ZONE.localize(
+        self._current_datetime = py_datetime.datetime.combine(
-            py_datetime.datetime.combine(date, time)
+            date, time, dt_util.DEFAULT_TIME_ZONE
         )
         self.async_write_ha_state()
 

homeassistant/components/radarr/sensor.py

@@ -3,7 +3,6 @@ from datetime import datetime, timedelta
 import logging
 import time
 
-from pytz import timezone
 import requests
 import voluptuous as vol
 
@@ -26,6 +25,7 @@ from homeassistant.const import (
     HTTP_OK,
 )
 import homeassistant.helpers.config_validation as cv
+from homeassistant.util import dt as dt_util
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -112,7 +112,6 @@ class RadarrSensor(SensorEntity):
         self.ssl = "https" if conf.get(CONF_SSL) else "http"
         self._state = None
         self.data = []
-        self._tz = timezone(str(hass.config.time_zone))
         self.type = sensor_type
         self._name = SENSOR_TYPES[self.type][0]
         if self.type == "diskspace":
@@ -177,8 +176,9 @@ class RadarrSensor(SensorEntity):
 
     def update(self):
         """Update the data for the sensor."""
-        start = get_date(self._tz)
+        time_zone = dt_util.get_time_zone(self.hass.config.time_zone)
-        end = get_date(self._tz, self.days)
+        start = get_date(time_zone)
+        end = get_date(time_zone, self.days)
         try:
             res = requests.get(
                 ENDPOINTS[self.type].format(

homeassistant/components/tod/binary_sensor.py

@@ -1,8 +1,8 @@
 """Support for representing current time of the day as binary sensors."""
 from datetime import datetime, timedelta
 import logging
+from typing import Callable
 
-import pytz
 import voluptuous as vol
 
 from homeassistant.components.binary_sensor import PLATFORM_SCHEMA, BinarySensorEntity
@@ -70,6 +70,7 @@ class TodSensor(BinarySensorEntity):
         self._before_offset = before_offset
         self._before = before
         self._after = after
+        self._unsub_update: Callable[[], None] = None
 
     @property
     def should_poll(self):
@@ -81,59 +82,37 @@ class TodSensor(BinarySensorEntity):
         """Return the name of the sensor."""
         return self._name
 
-    @property
-    def after(self):
-        """Return the timestamp for the beginning of the period."""
-        return self._time_after
-
-    @property
-    def before(self):
-        """Return the timestamp for the end of the period."""
-        return self._time_before
-
     @property
     def is_on(self):
         """Return True is sensor is on."""
-        if self.after < self.before:
+        if self._time_after < self._time_before:
-            return self.after <= self.current_datetime < self.before
+            return self._time_after <= dt_util.utcnow() < self._time_before
         return False
 
-    @property
-    def current_datetime(self):
-        """Return local current datetime according to hass configuration."""
-        return dt_util.utcnow()
-
-    @property
-    def next_update(self):
-        """Return the next update point in the UTC time."""
-        return self._next_update
-
     @property
     def extra_state_attributes(self):
         """Return the state attributes of the sensor."""
+        time_zone = dt_util.get_time_zone(self.hass.config.time_zone)
         return {
-            ATTR_AFTER: self.after.astimezone(self.hass.config.time_zone).isoformat(),
+            ATTR_AFTER: self._time_after.astimezone(time_zone).isoformat(),
-            ATTR_BEFORE: self.before.astimezone(self.hass.config.time_zone).isoformat(),
+            ATTR_BEFORE: self._time_before.astimezone(time_zone).isoformat(),
-            ATTR_NEXT_UPDATE: self.next_update.astimezone(
+            ATTR_NEXT_UPDATE: self._next_update.astimezone(time_zone).isoformat(),
-                self.hass.config.time_zone
-            ).isoformat(),
         }
 
     def _naive_time_to_utc_datetime(self, naive_time):
         """Convert naive time from config to utc_datetime with current day."""
         # get the current local date from utc time
-        current_local_date = self.current_datetime.astimezone(
+        current_local_date = (
-            self.hass.config.time_zone
+            dt_util.utcnow()
-        ).date()
+            .astimezone(dt_util.get_time_zone(self.hass.config.time_zone))
-        # calculate utc datetime corecponding to local time
+            .date()
-        utc_datetime = self.hass.config.time_zone.localize(
+        )
-            datetime.combine(current_local_date, naive_time)
+        # calculate utc datetime corresponding to local time
-        ).astimezone(tz=pytz.UTC)
+        return dt_util.as_utc(datetime.combine(current_local_date, naive_time))
-        return utc_datetime
 
-    def _calculate_initial_boudary_time(self):
+    def _calculate_boudary_time(self):
         """Calculate internal absolute time boundaries."""
-        nowutc = self.current_datetime
+        nowutc = dt_util.utcnow()
         # If after value is a sun event instead of absolute time
         if is_sun_event(self._after):
             # Calculate the today's event utc time or
@@ -177,43 +156,34 @@ class TodSensor(BinarySensorEntity):
         self._time_after += self._after_offset
         self._time_before += self._before_offset
 
-    def _turn_to_next_day(self):
-        """Turn to to the next day."""
-        if is_sun_event(self._after):
-            self._time_after = get_astral_event_next(
-                self.hass, self._after, self._time_after - self._after_offset
-            )
-            self._time_after += self._after_offset
-        else:
-            # Offset is already there
-            self._time_after += timedelta(days=1)
-
-        if is_sun_event(self._before):
-            self._time_before = get_astral_event_next(
-                self.hass, self._before, self._time_before - self._before_offset
-            )
-            self._time_before += self._before_offset
-        else:
-            # Offset is already there
-            self._time_before += timedelta(days=1)
-
     async def async_added_to_hass(self):
         """Call when entity about to be added to Home Assistant."""
-        self._calculate_initial_boudary_time()
+        self._calculate_boudary_time()
         self._calculate_next_update()
-        self._point_in_time_listener(dt_util.now())
+
+        @callback
+        def _clean_up_listener():
+            if self._unsub_update is not None:
+                self._unsub_update()
+                self._unsub_update = None
+
+        self.async_on_remove(_clean_up_listener)
+
+        self._unsub_update = event.async_track_point_in_utc_time(
+            self.hass, self._point_in_time_listener, self._next_update
+        )
 
     def _calculate_next_update(self):
         """Datetime when the next update to the state."""
-        now = self.current_datetime
+        now = dt_util.utcnow()
-        if now < self.after:
+        if now < self._time_after:
-            self._next_update = self.after
+            self._next_update = self._time_after
             return
-        if now < self.before:
+        if now < self._time_before:
-            self._next_update = self.before
+            self._next_update = self._time_before
             return
-        self._turn_to_next_day()
+        self._calculate_boudary_time()
-        self._next_update = self.after
+        self._next_update = self._time_after
 
     @callback
     def _point_in_time_listener(self, now):
@@ -221,6 +191,6 @@ class TodSensor(BinarySensorEntity):
         self._calculate_next_update()
         self.async_write_ha_state()
 
-        event.async_track_point_in_utc_time(
+        self._unsub_update = event.async_track_point_in_utc_time(
-            self.hass, self._point_in_time_listener, self.next_update
+            self.hass, self._point_in_time_listener, self._next_update
         )

homeassistant/components/zamg/sensor.py

@@ -7,7 +7,6 @@ import logging
 import os
 
 from aiohttp.hdrs import USER_AGENT
-import pytz
 import requests
 import voluptuous as vol
 
@@ -28,7 +27,7 @@ from homeassistant.const import (
     __version__,
 )
 import homeassistant.helpers.config_validation as cv
-from homeassistant.util import Throttle
+from homeassistant.util import Throttle, dt as dt_util
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -41,6 +40,7 @@ CONF_STATION_ID = "station_id"
 DEFAULT_NAME = "zamg"
 
 MIN_TIME_BETWEEN_UPDATES = timedelta(minutes=10)
+VIENNA_TIME_ZONE = dt_util.get_time_zone("Europe/Vienna")
 
 SENSOR_TYPES = {
     "pressure": ("Pressure", PRESSURE_HPA, "LDstat hPa", float),
@@ -187,7 +187,7 @@ class ZamgData:
         date, time = self.data.get("update_date"), self.data.get("update_time")
         if date is not None and time is not None:
             return datetime.strptime(date + time, "%d-%m-%Y%H:%M").replace(
-                tzinfo=pytz.timezone("Europe/Vienna")
+                tzinfo=VIENNA_TIME_ZONE
             )
 
     @classmethod
@@ -208,7 +208,7 @@ class ZamgData:
         """Get the latest data from ZAMG."""
         if self.last_update and (
             self.last_update + timedelta(hours=1)
-            > datetime.utcnow().replace(tzinfo=pytz.utc)
+            > datetime.utcnow().replace(tzinfo=dt_util.UTC)
         ):
             return  # Not time to update yet; data is only hourly
 

homeassistant/core.py

@@ -1531,7 +1531,7 @@ class Config:
         self.longitude: float = 0
         self.elevation: int = 0
         self.location_name: str = "Home"
-        self.time_zone: datetime.tzinfo = dt_util.UTC
+        self.time_zone: str = "UTC"
         self.units: UnitSystem = METRIC_SYSTEM
         self.internal_url: str | None = None
         self.external_url: str | None = None
@@ -1621,17 +1621,13 @@ class Config:
 
         Async friendly.
         """
-        time_zone = dt_util.UTC.zone
-        if self.time_zone and getattr(self.time_zone, "zone"):
-            time_zone = getattr(self.time_zone, "zone")
-
         return {
             "latitude": self.latitude,
             "longitude": self.longitude,
             "elevation": self.elevation,
             "unit_system": self.units.as_dict(),
             "location_name": self.location_name,
-            "time_zone": time_zone,
+            "time_zone": self.time_zone,
             "components": self.components,
             "config_dir": self.config_dir,
             # legacy, backwards compat
@@ -1651,7 +1647,7 @@ class Config:
         time_zone = dt_util.get_time_zone(time_zone_str)
 
         if time_zone:
-            self.time_zone = time_zone
+            self.time_zone = time_zone_str
             dt_util.set_default_time_zone(time_zone)
         else:
             raise ValueError(f"Received invalid time zone {time_zone_str}")
@@ -1721,17 +1717,13 @@ class Config:
 
     async def async_store(self) -> None:
         """Store [homeassistant] core config."""
-        time_zone = dt_util.UTC.zone
-        if self.time_zone and getattr(self.time_zone, "zone"):
-            time_zone = getattr(self.time_zone, "zone")
-
         data = {
             "latitude": self.latitude,
             "longitude": self.longitude,
             "elevation": self.elevation,
             "unit_system": self.units.name,
             "location_name": self.location_name,
-            "time_zone": time_zone,
+            "time_zone": self.time_zone,
             "external_url": self.external_url,
             "internal_url": self.internal_url,
         }

homeassistant/package_constraints.txt

@@ -24,8 +24,8 @@ paho-mqtt==1.5.1
 pillow==8.1.2
 pip>=8.0.3,<20.3
 pyroute2==0.5.18
+python-dateutil==2.8.1
 python-slugify==4.0.1
-pytz>=2021.1
 pyyaml==5.4.1
 requests==2.25.1
 ruamel.yaml==0.15.100

homeassistant/util/dt.py

@@ -4,20 +4,16 @@ from __future__ import annotations
 from contextlib import suppress
 import datetime as dt
 import re
-from typing import Any, cast
+from typing import Any
 
 import ciso8601
-import pytz
+from dateutil import tz
-import pytz.exceptions as pytzexceptions
-import pytz.tzinfo as pytzinfo
 
 from homeassistant.const import MATCH_ALL
 
 DATE_STR_FORMAT = "%Y-%m-%d"
-NATIVE_UTC = dt.timezone.utc
+UTC = dt.timezone.utc
-UTC = pytz.utc
+DEFAULT_TIME_ZONE: dt.tzinfo = dt.timezone.utc
-DEFAULT_TIME_ZONE: dt.tzinfo = pytz.utc
-
 
 # Copyright (c) Django Software Foundation and individual contributors.
 # All rights reserved.
@@ -37,7 +33,6 @@ def set_default_time_zone(time_zone: dt.tzinfo) -> None:
     """
     global DEFAULT_TIME_ZONE  # pylint: disable=global-statement
 
-    # NOTE: Remove in the future in favour of typing
     assert isinstance(time_zone, dt.tzinfo)
 
     DEFAULT_TIME_ZONE = time_zone
@@ -48,15 +43,12 @@ def get_time_zone(time_zone_str: str) -> dt.tzinfo | None:
 
     Async friendly.
     """
-    try:
+    return tz.gettz(time_zone_str)
-        return pytz.timezone(time_zone_str)
-    except pytzexceptions.UnknownTimeZoneError:
-        return None
 
 
 def utcnow() -> dt.datetime:
     """Get now in UTC time."""
-    return dt.datetime.now(NATIVE_UTC)
+    return dt.datetime.now(UTC)
 
 
 def now(time_zone: dt.tzinfo | None = None) -> dt.datetime:
@@ -72,7 +64,7 @@ def as_utc(dattim: dt.datetime) -> dt.datetime:
     if dattim.tzinfo == UTC:
         return dattim
     if dattim.tzinfo is None:
-        dattim = DEFAULT_TIME_ZONE.localize(dattim)  # type: ignore
+        dattim = dattim.replace(tzinfo=DEFAULT_TIME_ZONE)
 
     return dattim.astimezone(UTC)
 
@@ -93,14 +85,14 @@ def as_local(dattim: dt.datetime) -> dt.datetime:
     if dattim.tzinfo == DEFAULT_TIME_ZONE:
         return dattim
     if dattim.tzinfo is None:
-        dattim = UTC.localize(dattim)
+        dattim = dattim.replace(tzinfo=DEFAULT_TIME_ZONE)
 
     return dattim.astimezone(DEFAULT_TIME_ZONE)
 
 
 def utc_from_timestamp(timestamp: float) -> dt.datetime:
     """Return a UTC time from a timestamp."""
-    return UTC.localize(dt.datetime.utcfromtimestamp(timestamp))
+    return dt.datetime.utcfromtimestamp(timestamp).replace(tzinfo=UTC)
 
 
 def start_of_local_day(dt_or_d: dt.date | dt.datetime | None = None) -> dt.datetime:
@@ -112,9 +104,7 @@ def start_of_local_day(dt_or_d: dt.date | dt.datetime | None = None) -> dt.datet
     else:
         date = dt_or_d
 
-    return DEFAULT_TIME_ZONE.localize(  # type: ignore
+    return dt.datetime.combine(date, dt.time(), tzinfo=DEFAULT_TIME_ZONE)
-        dt.datetime.combine(date, dt.time())
-    )
 
 
 # Copyright (c) Django Software Foundation and individual contributors.
@@ -239,6 +229,12 @@ def parse_time_expression(parameter: Any, min_value: int, max_value: int) -> lis
     return res
 
 
+def _dst_offset_diff(dattim: dt.datetime) -> dt.timedelta:
+    """Return the offset when crossing the DST barrier."""
+    delta = dt.timedelta(hours=24)
+    return (dattim + delta).utcoffset() - (dattim - delta).utcoffset()  # type: ignore[operator]
+
+
 def find_next_time_expression_time(
     now: dt.datetime,  # pylint: disable=redefined-outer-name
     seconds: list[int],
@@ -312,38 +308,28 @@ def find_next_time_expression_time(
 
     result = result.replace(hour=next_hour)
 
-    if result.tzinfo is None:
+    if result.tzinfo in (None, UTC):
         return result
 
-    # Now we need to handle timezones. We will make this datetime object
+    if tz.datetime_ambiguous(result):
-    # "naive" first and then re-convert it to the target timezone.
-    # This is so that we can call pytz's localize and handle DST changes.
-    tzinfo: pytzinfo.DstTzInfo = UTC if result.tzinfo == NATIVE_UTC else result.tzinfo
-    result = result.replace(tzinfo=None)
-
-    try:
-        result = tzinfo.localize(result, is_dst=None)
-    except pytzexceptions.AmbiguousTimeError:
         # This happens when we're leaving daylight saving time and local
         # clocks are rolled back. In this case, we want to trigger
         # on both the DST and non-DST time. So when "now" is in the DST
         # use the DST-on time, and if not, use the DST-off time.
-        use_dst = bool(now.dst())
+        fold = 1 if now.dst() else 0
-        result = tzinfo.localize(result, is_dst=use_dst)
+        if result.fold != fold:
-    except pytzexceptions.NonExistentTimeError:
+            result = result.replace(fold=fold)
+
+    if not tz.datetime_exists(result):
         # This happens when we're entering daylight saving time and local
         # clocks are rolled forward, thus there are local times that do
         # not exist. In this case, we want to trigger on the next time
         # that *does* exist.
         # In the worst case, this will run through all the seconds in the
         # time shift, but that's max 3600 operations for once per year
-        result = result.replace(tzinfo=tzinfo) + dt.timedelta(seconds=1)
+        return find_next_time_expression_time(
-        return find_next_time_expression_time(result, seconds, minutes, hours)
+            result + dt.timedelta(seconds=1), seconds, minutes, hours
-
+        )
-    result_dst = cast(dt.timedelta, result.dst())
-    now_dst = cast(dt.timedelta, now.dst()) or dt.timedelta(0)
-    if result_dst >= now_dst:
-        return result
 
     # Another edge-case when leaving DST:
     # When now is in DST and ambiguous *and* the next trigger time we *should*
@@ -351,23 +337,11 @@ def find_next_time_expression_time(
     # For example: if triggering on 2:30 and now is 28.10.2018 2:30 (in DST)
     # we should trigger next on 28.10.2018 2:30 (out of DST), but our
     # algorithm above would produce 29.10.2018 2:30 (out of DST)
-
+    if tz.datetime_ambiguous(now):
-    # Step 1: Check if now is ambiguous
+        check_result = find_next_time_expression_time(
-    try:
+            now + _dst_offset_diff(now), seconds, minutes, hours
-        tzinfo.localize(now.replace(tzinfo=None), is_dst=None)
+        )
-        return result
+        if tz.datetime_ambiguous(check_result):
-    except pytzexceptions.AmbiguousTimeError:
-        pass
-
-    # Step 2: Check if result of (now - DST) is ambiguous.
-    check = now - now_dst
-    check_result = find_next_time_expression_time(check, seconds, minutes, hours)
-    try:
-        tzinfo.localize(check_result.replace(tzinfo=None), is_dst=None)
-        return result
-    except pytzexceptions.AmbiguousTimeError:
-        pass
-
-    # OK, edge case does apply. We must override the DST to DST-off
-    check_result = tzinfo.localize(check_result.replace(tzinfo=None), is_dst=False)
             return check_result
+
+    return result

requirements.txt

@@ -15,7 +15,7 @@ PyJWT==1.7.1
 cryptography==3.3.2
 pip>=8.0.3,<20.3
 python-slugify==4.0.1
-pytz>=2021.1
+python-dateutil==2.8.1
 pyyaml==5.4.1
 requests==2.25.1
 ruamel.yaml==0.15.100

setup.py

@@ -47,7 +47,7 @@ REQUIRES = [
     "cryptography==3.3.2",
     "pip>=8.0.3,<20.3",
     "python-slugify==4.0.1",
-    "pytz>=2021.1",
+    "python-dateutil==2.8.1",
     "pyyaml==5.4.1",
     "requests==2.25.1",
     "ruamel.yaml==0.15.100",

tests/common.py

@@ -270,7 +270,7 @@ async def async_test_home_assistant(loop, load_registries=True):
     hass.config.latitude = 32.87336
     hass.config.longitude = -117.22743
     hass.config.elevation = 0
-    hass.config.time_zone = date_util.get_time_zone("US/Pacific")
+    hass.config.time_zone = "US/Pacific"
     hass.config.units = METRIC_SYSTEM
     hass.config.media_dirs = {"local": get_test_config_dir("media")}
     hass.config.skip_pip = True

tests/components/climacell/test_sensor.py

@@ -7,7 +7,6 @@ from typing import Any
 from unittest.mock import patch
 
 import pytest
-import pytz
 
 from homeassistant.components.climacell.config_flow import (
     _get_config_schema,
@@ -18,6 +17,7 @@ from homeassistant.components.sensor import DOMAIN as SENSOR_DOMAIN
 from homeassistant.const import ATTR_ATTRIBUTION
 from homeassistant.core import HomeAssistant, State, callback
 from homeassistant.helpers.entity_registry import async_get
+from homeassistant.util import dt as dt_util
 
 from .const import API_V3_ENTRY_DATA, API_V4_ENTRY_DATA
 
@@ -59,7 +59,7 @@ async def _setup(hass: HomeAssistant, config: dict[str, Any]) -> State:
     """Set up entry and return entity state."""
     with patch(
         "homeassistant.util.dt.utcnow",
-        return_value=datetime(2021, 3, 6, 23, 59, 59, tzinfo=pytz.UTC),
+        return_value=datetime(2021, 3, 6, 23, 59, 59, tzinfo=dt_util.UTC),
     ):
         data = _get_config_schema(hass)(config)
         config_entry = MockConfigEntry(

tests/components/climacell/test_weather.py

@@ -7,7 +7,6 @@ from typing import Any
 from unittest.mock import patch
 
 import pytest
-import pytz
 
 from homeassistant.components.climacell.config_flow import (
     _get_config_schema,
@@ -46,6 +45,7 @@ from homeassistant.components.weather import (
 from homeassistant.const import ATTR_ATTRIBUTION, ATTR_FRIENDLY_NAME
 from homeassistant.core import HomeAssistant, State, callback
 from homeassistant.helpers.entity_registry import async_get
+from homeassistant.util import dt as dt_util
 
 from .const import API_V3_ENTRY_DATA, API_V4_ENTRY_DATA
 
@@ -70,7 +70,7 @@ async def _setup(hass: HomeAssistant, config: dict[str, Any]) -> State:
     """Set up entry and return entity state."""
     with patch(
         "homeassistant.util.dt.utcnow",
-        return_value=datetime(2021, 3, 6, 23, 59, 59, tzinfo=pytz.UTC),
+        return_value=datetime(2021, 3, 6, 23, 59, 59, tzinfo=dt_util.UTC),
     ):
         data = _get_config_schema(hass)(config)
         config_entry = MockConfigEntry(

tests/components/config/test_core.py

@@ -57,7 +57,7 @@ async def test_websocket_core_update(hass, client):
     assert hass.config.elevation != 25
     assert hass.config.location_name != "Huis"
     assert hass.config.units.name != CONF_UNIT_SYSTEM_IMPERIAL
-    assert hass.config.time_zone.zone != "America/New_York"
+    assert hass.config.time_zone != "America/New_York"
     assert hass.config.external_url != "https://www.example.com"
     assert hass.config.internal_url != "http://example.com"
 
@@ -91,7 +91,7 @@ async def test_websocket_core_update(hass, client):
     assert hass.config.internal_url == "http://example.local"
 
     assert len(mock_set_tz.mock_calls) == 1
-    assert mock_set_tz.mock_calls[0][1][0].zone == "America/New_York"
+    assert mock_set_tz.mock_calls[0][1][0] == dt_util.get_time_zone("America/New_York")
 
 
 async def test_websocket_core_update_not_admin(hass, hass_ws_client, hass_admin_user):

tests/components/generic_thermostat/test_climate.py

@@ -4,7 +4,6 @@ from os import path
 from unittest.mock import patch
 
 import pytest
-import pytz
 import voluptuous as vol
 
 from homeassistant import config as hass_config
@@ -37,6 +36,7 @@ import homeassistant.core as ha
 from homeassistant.core import DOMAIN as HASS_DOMAIN, CoreState, State, callback
 from homeassistant.helpers import entity_registry as er
 from homeassistant.setup import async_setup_component
+from homeassistant.util import dt as dt_util
 from homeassistant.util.unit_system import METRIC_SYSTEM
 
 from tests.common import (
@@ -691,9 +691,7 @@ async def test_temp_change_ac_trigger_on_not_long_enough(hass, setup_comp_4):
 
 async def test_temp_change_ac_trigger_on_long_enough(hass, setup_comp_4):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -719,9 +717,7 @@ async def test_temp_change_ac_trigger_off_not_long_enough(hass, setup_comp_4):
 
 async def test_temp_change_ac_trigger_off_long_enough(hass, setup_comp_4):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -801,9 +797,7 @@ async def test_temp_change_ac_trigger_on_not_long_enough_2(hass, setup_comp_5):
 
 async def test_temp_change_ac_trigger_on_long_enough_2(hass, setup_comp_5):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -829,9 +823,7 @@ async def test_temp_change_ac_trigger_off_not_long_enough_2(hass, setup_comp_5):
 
 async def test_temp_change_ac_trigger_off_long_enough_2(hass, setup_comp_5):
     """Test if temperature change turn ac on."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -919,9 +911,7 @@ async def test_temp_change_heater_trigger_on_not_long_enough(hass, setup_comp_6)
 
 async def test_temp_change_heater_trigger_on_long_enough(hass, setup_comp_6):
     """Test if temperature change turn heater on after min cycle."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -938,9 +928,7 @@ async def test_temp_change_heater_trigger_on_long_enough(hass, setup_comp_6):
 
 async def test_temp_change_heater_trigger_off_long_enough(hass, setup_comp_6):
     """Test if temperature change turn heater off after min cycle."""
-    fake_changed = datetime.datetime(
+    fake_changed = datetime.datetime(1918, 11, 11, 11, 11, 11, tzinfo=dt_util.UTC)
-        1918, 11, 11, 11, 11, 11, tzinfo=datetime.timezone.utc
-    )
     with patch(
         "homeassistant.helpers.condition.dt_util.utcnow", return_value=fake_changed
     ):
@@ -1019,7 +1007,7 @@ async def test_temp_change_ac_trigger_on_long_enough_3(hass, setup_comp_7):
     _setup_sensor(hass, 30)
     await hass.async_block_till_done()
     await common.async_set_temperature(hass, 25)
-    test_time = datetime.datetime.now(pytz.UTC)
+    test_time = datetime.datetime.now(dt_util.UTC)
     async_fire_time_changed(hass, test_time)
     await hass.async_block_till_done()
     assert len(calls) == 0
@@ -1042,7 +1030,7 @@ async def test_temp_change_ac_trigger_off_long_enough_3(hass, setup_comp_7):
     _setup_sensor(hass, 20)
     await hass.async_block_till_done()
     await common.async_set_temperature(hass, 25)
-    test_time = datetime.datetime.now(pytz.UTC)
+    test_time = datetime.datetime.now(dt_util.UTC)
     async_fire_time_changed(hass, test_time)
     await hass.async_block_till_done()
     assert len(calls) == 0
@@ -1090,7 +1078,7 @@ async def test_temp_change_heater_trigger_on_long_enough_2(hass, setup_comp_8):
     _setup_sensor(hass, 20)
     await hass.async_block_till_done()
     await common.async_set_temperature(hass, 25)
-    test_time = datetime.datetime.now(pytz.UTC)
+    test_time = datetime.datetime.now(dt_util.UTC)
     async_fire_time_changed(hass, test_time)
     await hass.async_block_till_done()
     assert len(calls) == 0
@@ -1113,7 +1101,7 @@ async def test_temp_change_heater_trigger_off_long_enough_2(hass, setup_comp_8):
     _setup_sensor(hass, 30)
     await hass.async_block_till_done()
     await common.async_set_temperature(hass, 25)
-    test_time = datetime.datetime.now(pytz.UTC)
+    test_time = datetime.datetime.now(dt_util.UTC)
     async_fire_time_changed(hass, test_time)
     await hass.async_block_till_done()
     assert len(calls) == 0

tests/components/history_stats/test_sensor.py

@@ -6,7 +6,6 @@ import unittest
 from unittest.mock import patch
 
 import pytest
-import pytz
 
 from homeassistant import config as hass_config
 from homeassistant.components.history_stats import DOMAIN
@@ -82,7 +81,7 @@ class TestHistoryStatsSensor(unittest.TestCase):
     )
     def test_period_parsing(self, mock):
         """Test the conversion from templates to period."""
-        now = datetime(2019, 1, 1, 23, 30, 0, tzinfo=pytz.utc)
+        now = datetime(2019, 1, 1, 23, 30, 0, tzinfo=dt_util.UTC)
         with patch("homeassistant.util.dt.now", return_value=now):
             today = Template(
                 "{{ now().replace(hour=0).replace(minute=0).replace(second=0) }}",

tests/components/jewish_calendar/__init__.py

@@ -26,7 +26,9 @@ def make_nyc_test_params(dtime, results, havdalah_offset=0):
     if isinstance(results, dict):
         time_zone = dt_util.get_time_zone("America/New_York")
         results = {
-            key: time_zone.localize(value) if isinstance(value, datetime) else value
+            key: value.replace(tzinfo=time_zone)
+            if isinstance(value, datetime)
+            else value
             for key, value in results.items()
         }
     return (
@@ -46,7 +48,9 @@ def make_jerusalem_test_params(dtime, results, havdalah_offset=0):
     if isinstance(results, dict):
         time_zone = dt_util.get_time_zone("Asia/Jerusalem")
         results = {
-            key: time_zone.localize(value) if isinstance(value, datetime) else value
+            key: value.replace(tzinfo=time_zone)
+            if isinstance(value, datetime)
+            else value
             for key, value in results.items()
         }
     return (

tests/components/jewish_calendar/test_binary_sensor.py

@@ -179,9 +179,9 @@ async def test_issur_melacha_sensor(
 ):
     """Test Issur Melacha sensor output."""
     time_zone = dt_util.get_time_zone(tzname)
-    test_time = time_zone.localize(now)
+    test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = time_zone
+    hass.config.time_zone = tzname
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
@@ -214,7 +214,7 @@ async def test_issur_melacha_sensor(
                 [
                     latitude,
                     longitude,
-                    time_zone,
+                    tzname,
                     HDATE_DEFAULT_ALTITUDE,
                     diaspora,
                     "english",
@@ -270,9 +270,9 @@ async def test_issur_melacha_sensor_update(
 ):
     """Test Issur Melacha sensor output."""
     time_zone = dt_util.get_time_zone(tzname)
-    test_time = time_zone.localize(now)
+    test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = time_zone
+    hass.config.time_zone = tzname
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 

tests/components/jewish_calendar/test_sensor.py

@@ -163,9 +163,9 @@ async def test_jewish_calendar_sensor(
 ):
     """Test Jewish calendar sensor output."""
     time_zone = dt_util.get_time_zone(tzname)
-    test_time = time_zone.localize(now)
+    test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = time_zone
+    hass.config.time_zone = tzname
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
@@ -188,7 +188,9 @@ async def test_jewish_calendar_sensor(
         await hass.async_block_till_done()
 
     result = (
-        dt_util.as_utc(time_zone.localize(result)) if isinstance(result, dt) else result
+        dt_util.as_utc(result.replace(tzinfo=time_zone))
+        if isinstance(result, dt)
+        else result
     )
 
     sensor_object = hass.states.get(f"sensor.test_{sensor}")
@@ -506,9 +508,9 @@ async def test_shabbat_times_sensor(
 ):
     """Test sensor output for upcoming shabbat/yomtov times."""
     time_zone = dt_util.get_time_zone(tzname)
-    test_time = time_zone.localize(now)
+    test_time = now.replace(tzinfo=time_zone)
 
-    hass.config.time_zone = time_zone
+    hass.config.time_zone = tzname
     hass.config.latitude = latitude
     hass.config.longitude = longitude
 
@@ -559,7 +561,7 @@ async def test_shabbat_times_sensor(
                 [
                     latitude,
                     longitude,
-                    time_zone,
+                    tzname,
                     HDATE_DEFAULT_ALTITUDE,
                     diaspora,
                     language,
@@ -593,7 +595,7 @@ OMER_TEST_IDS = [
 @pytest.mark.parametrize(["test_time", "result"], OMER_PARAMS, ids=OMER_TEST_IDS)
 async def test_omer_sensor(hass, legacy_patchable_time, test_time, result):
     """Test Omer Count sensor output."""
-    test_time = hass.config.time_zone.localize(test_time)
+    test_time = test_time.replace(tzinfo=dt_util.get_time_zone(hass.config.time_zone))
 
     with alter_time(test_time):
         assert await async_setup_component(
@@ -627,7 +629,7 @@ DAFYOMI_TEST_IDS = [
 @pytest.mark.parametrize(["test_time", "result"], DAFYOMI_PARAMS, ids=DAFYOMI_TEST_IDS)
 async def test_dafyomi_sensor(hass, legacy_patchable_time, test_time, result):
     """Test Daf Yomi sensor output."""
-    test_time = hass.config.time_zone.localize(test_time)
+    test_time = test_time.replace(tzinfo=dt_util.get_time_zone(hass.config.time_zone))
 
     with alter_time(test_time):
         assert await async_setup_component(

tests/components/pvpc_hourly_pricing/test_config_flow.py

@@ -2,12 +2,11 @@
 from datetime import datetime
 from unittest.mock import patch
 
-from pytz import timezone
-
 from homeassistant import config_entries, data_entry_flow
 from homeassistant.components.pvpc_hourly_pricing import ATTR_TARIFF, DOMAIN
 from homeassistant.const import CONF_NAME
 from homeassistant.helpers import entity_registry as er
+from homeassistant.util import dt as dt_util
 
 from .conftest import check_valid_state
 
@@ -26,7 +25,7 @@ async def test_config_flow(
     - Check abort when trying to config another with same tariff
     - Check removal and add again to check state restoration
     """
-    hass.config.time_zone = timezone("Europe/Madrid")
+    hass.config.time_zone = dt_util.get_time_zone("Europe/Madrid")
     mock_data = {"return_time": datetime(2019, 10, 26, 14, 0, tzinfo=date_util.UTC)}
 
     def mock_now():

tests/components/pvpc_hourly_pricing/test_sensor.py

@@ -3,12 +3,11 @@ from datetime import datetime, timedelta
 import logging
 from unittest.mock import patch
 
-from pytz import timezone
-
 from homeassistant.components.pvpc_hourly_pricing import ATTR_TARIFF, DOMAIN
 from homeassistant.const import CONF_NAME
 from homeassistant.core import ATTR_NOW, EVENT_TIME_CHANGED
 from homeassistant.setup import async_setup_component
+from homeassistant.util import dt as dt_util
 
 from .conftest import check_valid_state
 
@@ -32,7 +31,7 @@ async def test_sensor_availability(
     hass, caplog, legacy_patchable_time, pvpc_aioclient_mock: AiohttpClientMocker
 ):
     """Test sensor availability and handling of cloud access."""
-    hass.config.time_zone = timezone("Europe/Madrid")
+    hass.config.time_zone = dt_util.get_time_zone("Europe/Madrid")
     config = {DOMAIN: [{CONF_NAME: "test_dst", ATTR_TARIFF: "discrimination"}]}
     mock_data = {"return_time": datetime(2019, 10, 27, 20, 0, 0, tzinfo=date_util.UTC)}
 

tests/components/recorder/models_original.py

@@ -170,5 +170,5 @@ def _process_timestamp(ts):
     if ts is None:
         return None
     if ts.tzinfo is None:
-        return dt_util.UTC.localize(ts)
+        return ts.replace(tzinfo=dt_util.UTC)
     return dt_util.as_utc(ts)

tests/components/recorder/test_init.py

@@ -604,7 +604,7 @@ def test_auto_purge(hass_recorder):
     #
     # The clock is started at 4:15am then advanced forward below
     now = dt_util.utcnow()
-    test_time = tz.localize(datetime(now.year + 2, 1, 1, 4, 15, 0))
+    test_time = datetime(now.year + 2, 1, 1, 4, 15, 0, tzinfo=tz)
     run_tasks_at_time(hass, test_time)
 
     with patch(

tests/components/recorder/test_models.py

@@ -2,7 +2,6 @@
 from datetime import datetime
 
 import pytest
-import pytz
 from sqlalchemy import create_engine
 from sqlalchemy.orm import scoped_session, sessionmaker
 
@@ -144,11 +143,11 @@ async def test_process_timestamp():
     """Test processing time stamp to UTC."""
     datetime_with_tzinfo = datetime(2016, 7, 9, 11, 0, 0, tzinfo=dt.UTC)
     datetime_without_tzinfo = datetime(2016, 7, 9, 11, 0, 0)
-    est = pytz.timezone("US/Eastern")
+    est = dt_util.get_time_zone("US/Eastern")
     datetime_est_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=est)
-    nst = pytz.timezone("Canada/Newfoundland")
+    nst = dt_util.get_time_zone("Canada/Newfoundland")
     datetime_nst_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=nst)
-    hst = pytz.timezone("US/Hawaii")
+    hst = dt_util.get_time_zone("US/Hawaii")
     datetime_hst_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=hst)
 
     assert process_timestamp(datetime_with_tzinfo) == datetime(
@@ -158,13 +157,13 @@ async def test_process_timestamp():
         2016, 7, 9, 11, 0, 0, tzinfo=dt.UTC
     )
     assert process_timestamp(datetime_est_timezone) == datetime(
-        2016, 7, 9, 15, 56, tzinfo=dt.UTC
+        2016, 7, 9, 15, 0, tzinfo=dt.UTC
     )
     assert process_timestamp(datetime_nst_timezone) == datetime(
-        2016, 7, 9, 14, 31, tzinfo=dt.UTC
+        2016, 7, 9, 13, 30, tzinfo=dt.UTC
     )
     assert process_timestamp(datetime_hst_timezone) == datetime(
-        2016, 7, 9, 21, 31, tzinfo=dt.UTC
+        2016, 7, 9, 21, 0, tzinfo=dt.UTC
     )
     assert process_timestamp(None) is None
 
@@ -173,13 +172,13 @@ async def test_process_timestamp_to_utc_isoformat():
     """Test processing time stamp to UTC isoformat."""
     datetime_with_tzinfo = datetime(2016, 7, 9, 11, 0, 0, tzinfo=dt.UTC)
     datetime_without_tzinfo = datetime(2016, 7, 9, 11, 0, 0)
-    est = pytz.timezone("US/Eastern")
+    est = dt_util.get_time_zone("US/Eastern")
     datetime_est_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=est)
-    est = pytz.timezone("US/Eastern")
+    est = dt_util.get_time_zone("US/Eastern")
     datetime_est_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=est)
-    nst = pytz.timezone("Canada/Newfoundland")
+    nst = dt_util.get_time_zone("Canada/Newfoundland")
     datetime_nst_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=nst)
-    hst = pytz.timezone("US/Hawaii")
+    hst = dt_util.get_time_zone("US/Hawaii")
     datetime_hst_timezone = datetime(2016, 7, 9, 11, 0, 0, tzinfo=hst)
 
     assert (
@@ -192,15 +191,15 @@ async def test_process_timestamp_to_utc_isoformat():
     )
     assert (
         process_timestamp_to_utc_isoformat(datetime_est_timezone)
-        == "2016-07-09T15:56:00+00:00"
+        == "2016-07-09T15:00:00+00:00"
     )
     assert (
         process_timestamp_to_utc_isoformat(datetime_nst_timezone)
-        == "2016-07-09T14:31:00+00:00"
+        == "2016-07-09T13:30:00+00:00"
     )
     assert (
         process_timestamp_to_utc_isoformat(datetime_hst_timezone)
-        == "2016-07-09T21:31:00+00:00"
+        == "2016-07-09T21:00:00+00:00"
     )
     assert process_timestamp_to_utc_isoformat(None) is None
 

tests/components/sun/test_trigger.py

@@ -33,7 +33,7 @@ def calls(hass):
 def setup_comp(hass):
     """Initialize components."""
     mock_component(hass, "group")
-    dt_util.set_default_time_zone(hass.config.time_zone)
+    hass.config.set_time_zone(hass.config.time_zone)
     hass.loop.run_until_complete(
         async_setup_component(hass, sun.DOMAIN, {sun.DOMAIN: {sun.CONF_ELEVATION: 0}})
     )

tests/components/tod/test_binary_sensor.py

@@ -3,7 +3,6 @@ from datetime import datetime, timedelta
 from unittest.mock import patch
 
 import pytest
-import pytz
 
 from homeassistant.const import STATE_OFF, STATE_ON
 import homeassistant.core as ha
@@ -61,7 +60,7 @@ async def test_setup_no_sensors(hass):
 
 async def test_in_period_on_start(hass):
     """Test simple setting."""
-    test_time = datetime(2019, 1, 10, 18, 43, 0, tzinfo=hass.config.time_zone)
+    test_time = datetime(2019, 1, 10, 18, 43, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
             {
@@ -85,7 +84,7 @@ async def test_in_period_on_start(hass):
 
 async def test_midnight_turnover_before_midnight_inside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = datetime(2019, 1, 10, 22, 30, 0, tzinfo=hass.config.time_zone)
+    test_time = datetime(2019, 1, 10, 22, 30, 0, tzinfo=dt_util.UTC)
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Night", "after": "22:00", "before": "5:00"}
@@ -104,9 +103,7 @@ async def test_midnight_turnover_before_midnight_inside_period(hass):
 
 async def test_midnight_turnover_after_midnight_inside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = hass.config.time_zone.localize(
+    test_time = datetime(2019, 1, 10, 21, 0, 0, tzinfo=dt_util.UTC)
-        datetime(2019, 1, 10, 21, 0, 0)
-    ).astimezone(pytz.UTC)
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Night", "after": "22:00", "before": "5:00"}
@@ -140,9 +137,7 @@ async def test_midnight_turnover_after_midnight_inside_period(hass):
 
 async def test_midnight_turnover_before_midnight_outside_period(hass):
     """Test midnight turnover setting before midnight outside period."""
-    test_time = hass.config.time_zone.localize(
+    test_time = datetime(2019, 1, 10, 20, 30, 0, tzinfo=dt_util.UTC)
-        datetime(2019, 1, 10, 20, 30, 0)
-    ).astimezone(pytz.UTC)
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Night", "after": "22:00", "before": "5:00"}
@@ -161,9 +156,7 @@ async def test_midnight_turnover_before_midnight_outside_period(hass):
 
 async def test_midnight_turnover_after_midnight_outside_period(hass):
     """Test midnight turnover setting before midnight inside period ."""
-    test_time = hass.config.time_zone.localize(
+    test_time = datetime(2019, 1, 10, 20, 0, 0, tzinfo=dt_util.UTC)
-        datetime(2019, 1, 10, 20, 0, 0)
-    ).astimezone(pytz.UTC)
 
     config = {
         "binary_sensor": [
@@ -180,9 +173,7 @@ async def test_midnight_turnover_after_midnight_outside_period(hass):
     state = hass.states.get("binary_sensor.night")
     assert state.state == STATE_OFF
 
-    switchover_time = hass.config.time_zone.localize(
+    switchover_time = datetime(2019, 1, 11, 4, 59, 0, tzinfo=dt_util.UTC)
-        datetime(2019, 1, 11, 4, 59, 0)
-    ).astimezone(pytz.UTC)
     with patch(
         "homeassistant.components.tod.binary_sensor.dt_util.utcnow",
         return_value=switchover_time,
@@ -210,9 +201,7 @@ async def test_midnight_turnover_after_midnight_outside_period(hass):
 
 async def test_from_sunrise_to_sunset(hass):
     """Test period from sunrise to sunset."""
-    test_time = hass.config.time_zone.localize(datetime(2019, 1, 12)).astimezone(
+    test_time = datetime(2019, 1, 12, tzinfo=dt_util.UTC)
-        pytz.UTC
-    )
     sunrise = dt_util.as_local(
         get_astral_event_date(hass, "sunrise", dt_util.as_utc(test_time))
     )
@@ -311,9 +300,7 @@ async def test_from_sunrise_to_sunset(hass):
 
 async def test_from_sunset_to_sunrise(hass):
     """Test period from sunset to sunrise."""
-    test_time = hass.config.time_zone.localize(datetime(2019, 1, 12)).astimezone(
+    test_time = datetime(2019, 1, 12, tzinfo=dt_util.UTC)
-        pytz.UTC
-    )
     sunset = dt_util.as_local(get_astral_event_date(hass, "sunset", test_time))
     sunrise = dt_util.as_local(get_astral_event_next(hass, "sunrise", sunset))
     # assert sunset == sunrise
@@ -405,13 +392,13 @@ async def test_from_sunset_to_sunrise(hass):
 
 async def test_offset(hass):
     """Test offset."""
-    after = hass.config.time_zone.localize(datetime(2019, 1, 10, 18, 0, 0)).astimezone(
+    after = datetime(2019, 1, 10, 18, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        pytz.UTC
+        hours=1, minutes=34
-    ) + timedelta(hours=1, minutes=34)
+    )
 
-    before = hass.config.time_zone.localize(datetime(2019, 1, 10, 22, 0, 0)).astimezone(
+    before = datetime(2019, 1, 10, 22, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        pytz.UTC
+        hours=1, minutes=45
-    ) + timedelta(hours=1, minutes=45)
+    )
 
     entity_id = "binary_sensor.evening"
     config = {
@@ -484,9 +471,9 @@ async def test_offset(hass):
 
 async def test_offset_overnight(hass):
     """Test offset overnight."""
-    after = hass.config.time_zone.localize(datetime(2019, 1, 10, 18, 0, 0)).astimezone(
+    after = datetime(2019, 1, 10, 18, 0, 0, tzinfo=dt_util.UTC) + timedelta(
-        pytz.UTC
+        hours=1, minutes=34
-    ) + timedelta(hours=1, minutes=34)
+    )
     entity_id = "binary_sensor.evening"
     config = {
         "binary_sensor": [
@@ -528,9 +515,7 @@ async def test_norwegian_case_winter(hass):
     hass.config.latitude = 69.6
     hass.config.longitude = 18.8
 
-    test_time = hass.config.time_zone.localize(datetime(2010, 1, 1)).astimezone(
+    test_time = datetime(2010, 1, 1, tzinfo=dt_util.UTC)
-        pytz.UTC
-    )
     sunrise = dt_util.as_local(
         get_astral_event_next(hass, "sunrise", dt_util.as_utc(test_time))
     )
@@ -645,9 +630,7 @@ async def test_norwegian_case_summer(hass):
     hass.config.longitude = 18.8
     hass.config.elevation = 10.0
 
-    test_time = hass.config.time_zone.localize(datetime(2010, 6, 1)).astimezone(
+    test_time = datetime(2010, 6, 1, tzinfo=dt_util.UTC)
-        pytz.UTC
-    )
 
     sunrise = dt_util.as_local(
         get_astral_event_next(hass, "sunrise", dt_util.as_utc(test_time))
@@ -759,9 +742,7 @@ async def test_norwegian_case_summer(hass):
 
 async def test_sun_offset(hass):
     """Test sun event with offset."""
-    test_time = hass.config.time_zone.localize(datetime(2019, 1, 12)).astimezone(
+    test_time = datetime(2019, 1, 12, tzinfo=dt_util.UTC)
-        pytz.UTC
-    )
     sunrise = dt_util.as_local(
         get_astral_event_date(hass, "sunrise", dt_util.as_utc(test_time))
         + timedelta(hours=-1, minutes=-30)
@@ -881,30 +862,27 @@ async def test_sun_offset(hass):
 
 async def test_dst(hass):
     """Test sun event with offset."""
-    hass.config.time_zone = pytz.timezone("CET")
+    hass.config.time_zone = "CET"
-    test_time = hass.config.time_zone.localize(
+    test_time = datetime(2019, 3, 30, 3, 0, 0, tzinfo=dt_util.UTC)
-        datetime(2019, 3, 30, 3, 0, 0)
-    ).astimezone(pytz.UTC)
     config = {
         "binary_sensor": [
             {"platform": "tod", "name": "Day", "after": "2:30", "before": "2:40"}
         ]
     }
+    # Test DST:
     # after 2019-03-30 03:00 CET the next update should ge scheduled
     # at 3:30 not 2:30 local time
-    # Internally the
     entity_id = "binary_sensor.day"
-    testtime = test_time
     with patch(
         "homeassistant.components.tod.binary_sensor.dt_util.utcnow",
-        return_value=testtime,
+        return_value=test_time,
     ):
         await async_setup_component(hass, "binary_sensor", config)
         await hass.async_block_till_done()
 
         await hass.async_block_till_done()
         state = hass.states.get(entity_id)
-        assert state.attributes["after"] == "2019-03-31T03:30:00+02:00"
+        assert state.attributes["after"] == "2019-03-30T03:30:00+01:00"
-        assert state.attributes["before"] == "2019-03-31T03:40:00+02:00"
+        assert state.attributes["before"] == "2019-03-30T03:40:00+01:00"
-        assert state.attributes["next_update"] == "2019-03-31T03:30:00+02:00"
+        assert state.attributes["next_update"] == "2019-03-30T03:30:00+01:00"
         assert state.state == STATE_OFF

tests/components/withings/common.py

@@ -7,7 +7,6 @@ from urllib.parse import urlparse
 
 from aiohttp.test_utils import TestClient
 import arrow
-import pytz
 from withings_api.common import (
     MeasureGetMeasResponse,
     NotifyAppli,
@@ -40,6 +39,7 @@ from homeassistant.core import HomeAssistant
 from homeassistant.helpers import config_entry_oauth2_flow
 from homeassistant.helpers.config_entry_oauth2_flow import AUTH_CALLBACK_PATH
 from homeassistant.setup import async_setup_component
+from homeassistant.util import dt as dt_util
 
 from tests.test_util.aiohttp import AiohttpClientMocker
 
@@ -77,7 +77,7 @@ def new_profile_config(
             measuregrps=[],
             more=False,
             offset=0,
-            timezone=pytz.UTC,
+            timezone=dt_util.UTC,
             updatetime=arrow.get(12345),
         ),
         api_response_sleep_get_summary=api_response_sleep_get_summary

tests/components/withings/test_sensor.py

@@ -3,7 +3,6 @@ from typing import Any
 from unittest.mock import patch
 
 import arrow
-import pytz
 from withings_api.common import (
     GetSleepSummaryData,
     GetSleepSummarySerie,
@@ -29,6 +28,7 @@ from homeassistant.components.withings.const import Measurement
 from homeassistant.core import HomeAssistant, State
 from homeassistant.helpers import entity_registry as er
 from homeassistant.helpers.entity_registry import EntityRegistry
+from homeassistant.util import dt as dt_util
 
 from .common import ComponentFactory, new_profile_config
 
@@ -189,7 +189,7 @@ PERSON0 = new_profile_config(
             ),
         ),
         more=False,
-        timezone=pytz.UTC,
+        timezone=dt_util.UTC,
         updatetime=arrow.get("2019-08-01"),
         offset=0,
     ),
@@ -198,7 +198,7 @@ PERSON0 = new_profile_config(
         offset=0,
         series=(
             GetSleepSummarySerie(
-                timezone=pytz.UTC,
+                timezone=dt_util.UTC,
                 model=SleepModel.SLEEP_MONITOR,
                 startdate=arrow.get("2019-02-01"),
                 enddate=arrow.get("2019-02-01"),
@@ -225,7 +225,7 @@ PERSON0 = new_profile_config(
                 ),
             ),
             GetSleepSummarySerie(
-                timezone=pytz.UTC,
+                timezone=dt_util.UTC,
                 model=SleepModel.SLEEP_MONITOR,
                 startdate=arrow.get("2019-02-01"),
                 enddate=arrow.get("2019-02-01"),

tests/components/xiaomi_miio/test_vacuum.py

@@ -5,7 +5,6 @@ from unittest.mock import MagicMock, patch
 
 from miio import DeviceException
 import pytest
-from pytz import utc
 
 from homeassistant.components.vacuum import (
     ATTR_BATTERY_ICON,
@@ -55,6 +54,7 @@ from homeassistant.const import (
     STATE_ON,
     STATE_UNAVAILABLE,
 )
+from homeassistant.util import dt as dt_util
 
 from .test_config_flow import TEST_MAC
 
@@ -106,12 +106,12 @@ def mirobo_is_got_error_fixture():
     mock_timer_1 = MagicMock()
     mock_timer_1.enabled = True
     mock_timer_1.cron = "5 5 1 8 1"
-    mock_timer_1.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc)
+    mock_timer_1.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC)
 
     mock_timer_2 = MagicMock()
     mock_timer_2.enabled = False
     mock_timer_2.cron = "5 5 1 8 2"
-    mock_timer_2.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc)
+    mock_timer_2.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC)
 
     mock_vacuum.timer.return_value = [mock_timer_1, mock_timer_2]
 
@@ -180,12 +180,12 @@ def mirobo_is_on_fixture():
     mock_timer_1 = MagicMock()
     mock_timer_1.enabled = True
     mock_timer_1.cron = "5 5 1 8 1"
-    mock_timer_1.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc)
+    mock_timer_1.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC)
 
     mock_timer_2 = MagicMock()
     mock_timer_2.enabled = False
     mock_timer_2.cron = "5 5 1 8 2"
-    mock_timer_2.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc)
+    mock_timer_2.next_schedule = datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC)
 
     mock_vacuum.timer.return_value = [mock_timer_1, mock_timer_2]
 
@@ -255,12 +255,12 @@ async def test_xiaomi_vacuum_services(hass, caplog, mock_mirobo_is_got_error):
         {
             "enabled": True,
             "cron": "5 5 1 8 1",
-            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc),
+            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC),
         },
         {
             "enabled": False,
             "cron": "5 5 1 8 2",
-            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc),
+            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC),
         },
     ]
 
@@ -353,12 +353,12 @@ async def test_xiaomi_specific_services(hass, caplog, mock_mirobo_is_on):
         {
             "enabled": True,
             "cron": "5 5 1 8 1",
-            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc),
+            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC),
         },
         {
             "enabled": False,
             "cron": "5 5 1 8 2",
-            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=utc),
+            "next_schedule": datetime(2020, 5, 23, 13, 21, 10, tzinfo=dt_util.UTC),
         },
     ]
 

tests/components/zwave/test_init.py

@@ -5,7 +5,6 @@ from datetime import datetime
 from unittest.mock import MagicMock, patch
 
 import pytest
-from pytz import utc
 import voluptuous as vol
 
 from homeassistant.bootstrap import async_setup_component
@@ -19,6 +18,7 @@ from homeassistant.components.zwave import (
 from homeassistant.components.zwave.binary_sensor import get_device
 from homeassistant.const import ATTR_ENTITY_ID, ATTR_NAME
 from homeassistant.helpers import device_registry as dr, entity_registry as er
+from homeassistant.util import dt as dt_util
 
 from tests.common import async_fire_time_changed, mock_registry
 from tests.mock.zwave import MockEntityValues, MockNetwork, MockNode, MockValue
@@ -140,7 +140,7 @@ async def test_auto_heal_midnight(hass, mock_openzwave, legacy_patchable_time):
     network = hass.data[zwave.DATA_NETWORK]
     assert not network.heal.called
 
-    time = utc.localize(datetime(2017, 5, 6, 0, 0, 0))
+    time = datetime(2017, 5, 6, 0, 0, 0, tzinfo=dt_util.UTC)
     async_fire_time_changed(hass, time)
     await hass.async_block_till_done()
     await hass.async_block_till_done()
@@ -156,7 +156,7 @@ async def test_auto_heal_disabled(hass, mock_openzwave):
     network = hass.data[zwave.DATA_NETWORK]
     assert not network.heal.called
 
-    time = utc.localize(datetime(2017, 5, 6, 0, 0, 0))
+    time = datetime(2017, 5, 6, 0, 0, 0, tzinfo=dt_util.UTC)
     async_fire_time_changed(hass, time)
     await hass.async_block_till_done()
     assert not network.heal.called

tests/helpers/test_condition.py

@@ -27,7 +27,7 @@ def calls(hass):
 @pytest.fixture(autouse=True)
 def setup_comp(hass):
     """Initialize components."""
-    dt_util.set_default_time_zone(hass.config.time_zone)
+    hass.config.set_time_zone(hass.config.time_zone)
     hass.loop.run_until_complete(
         async_setup_component(hass, sun.DOMAIN, {sun.DOMAIN: {sun.CONF_ELEVATION: 0}})
     )

tests/helpers/test_event.py

@@ -2908,8 +2908,8 @@ async def test_periodic_task_entering_dst(hass):
     specific_runs = []
 
     now = dt_util.utcnow()
-    time_that_will_not_match_right_away = timezone.localize(
+    time_that_will_not_match_right_away = datetime(
-        datetime(now.year + 1, 3, 25, 2, 31, 0)
+        now.year + 1, 3, 25, 2, 31, 0, tzinfo=timezone
     )
 
     with patch(
@@ -2924,25 +2924,25 @@ async def test_periodic_task_entering_dst(hass):
         )
 
     async_fire_time_changed(
-        hass, timezone.localize(datetime(now.year + 1, 3, 25, 1, 50, 0, 999999))
+        hass, datetime(now.year + 1, 3, 25, 1, 50, 0, 999999, tzinfo=timezone)
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 0
 
     async_fire_time_changed(
-        hass, timezone.localize(datetime(now.year + 1, 3, 25, 3, 50, 0, 999999))
+        hass, datetime(now.year + 1, 3, 25, 3, 50, 0, 999999, tzinfo=timezone)
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 0
 
     async_fire_time_changed(
-        hass, timezone.localize(datetime(now.year + 1, 3, 26, 1, 50, 0, 999999))
+        hass, datetime(now.year + 1, 3, 26, 1, 50, 0, 999999, tzinfo=timezone)
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 0
 
     async_fire_time_changed(
-        hass, timezone.localize(datetime(now.year + 1, 3, 26, 2, 50, 0, 999999))
+        hass, datetime(now.year + 1, 3, 26, 2, 50, 0, 999999, tzinfo=timezone)
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 1
@@ -2958,8 +2958,8 @@ async def test_periodic_task_leaving_dst(hass):
 
     now = dt_util.utcnow()
 
-    time_that_will_not_match_right_away = timezone.localize(
+    time_that_will_not_match_right_away = datetime(
-        datetime(now.year + 1, 10, 28, 2, 28, 0), is_dst=True
+        now.year + 1, 10, 28, 2, 28, 0, tzinfo=timezone, fold=1
     )
 
     with patch(
@@ -2974,46 +2974,33 @@ async def test_periodic_task_leaving_dst(hass):
         )
 
     async_fire_time_changed(
-        hass,
+        hass, datetime(now.year + 1, 10, 28, 2, 5, 0, 999999, tzinfo=timezone, fold=0)
-        timezone.localize(
-            datetime(now.year + 1, 10, 28, 2, 5, 0, 999999), is_dst=False
-        ),
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 0
 
     async_fire_time_changed(
-        hass,
+        hass, datetime(now.year + 1, 10, 28, 2, 55, 0, 999999, tzinfo=timezone, fold=0)
-        timezone.localize(
-            datetime(now.year + 1, 10, 28, 2, 55, 0, 999999), is_dst=False
-        ),
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 1
 
     async_fire_time_changed(
         hass,
-        timezone.localize(
+        datetime(now.year + 2, 10, 28, 2, 45, 0, 999999, tzinfo=timezone, fold=1),
-            datetime(now.year + 2, 10, 28, 2, 45, 0, 999999), is_dst=True
-        ),
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 2
 
     async_fire_time_changed(
         hass,
-        timezone.localize(
+        datetime(now.year + 2, 10, 28, 2, 55, 0, 999999, tzinfo=timezone, fold=1),
-            datetime(now.year + 2, 10, 28, 2, 55, 0, 999999), is_dst=True
-        ),
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 2
 
     async_fire_time_changed(
-        hass,
+        hass, datetime(now.year + 2, 10, 28, 2, 55, 0, 999999, tzinfo=timezone, fold=1)
-        timezone.localize(
-            datetime(now.year + 2, 10, 28, 2, 55, 0, 999999), is_dst=True
-        ),
     )
     await hass.async_block_till_done()
     assert len(specific_runs) == 2
@@ -3224,7 +3211,7 @@ async def test_async_track_point_in_time_cancel(hass):
     await asyncio.sleep(0.2)
 
     assert len(times) == 1
-    assert times[0].tzinfo.zone == "US/Hawaii"
+    assert "US/Hawaii" in str(times[0].tzinfo)
 
 
 async def test_async_track_entity_registry_updated_event(hass):

tests/helpers/test_template.py

@@ -5,7 +5,6 @@ import random
 from unittest.mock import patch
 
 import pytest
-import pytz
 import voluptuous as vol
 
 from homeassistant.components import group
@@ -763,7 +762,7 @@ def test_render_with_possible_json_value_non_string_value(hass):
         hass,
     )
     value = datetime(2019, 1, 18, 12, 13, 14)
-    expected = str(pytz.utc.localize(value))
+    expected = str(value.replace(tzinfo=dt_util.UTC))
     assert tpl.async_render_with_possible_json_value(value) == expected
 
 

tests/test_config.py

@@ -374,7 +374,7 @@ async def test_loading_configuration_from_storage(hass, hass_storage):
     assert hass.config.elevation == 10
     assert hass.config.location_name == "Home"
     assert hass.config.units.name == CONF_UNIT_SYSTEM_METRIC
-    assert hass.config.time_zone.zone == "Europe/Copenhagen"
+    assert hass.config.time_zone == "Europe/Copenhagen"
     assert hass.config.external_url == "https://www.example.com"
     assert hass.config.internal_url == "http://example.local"
     assert len(hass.config.allowlist_external_dirs) == 3
@@ -405,7 +405,7 @@ async def test_loading_configuration_from_storage_with_yaml_only(hass, hass_stor
     assert hass.config.elevation == 10
     assert hass.config.location_name == "Home"
     assert hass.config.units.name == CONF_UNIT_SYSTEM_METRIC
-    assert hass.config.time_zone.zone == "Europe/Copenhagen"
+    assert hass.config.time_zone == "Europe/Copenhagen"
     assert len(hass.config.allowlist_external_dirs) == 3
     assert "/etc" in hass.config.allowlist_external_dirs
     assert hass.config.media_dirs == {"mymedia": "/usr"}
@@ -463,7 +463,7 @@ async def test_override_stored_configuration(hass, hass_storage):
     assert hass.config.elevation == 10
     assert hass.config.location_name == "Home"
     assert hass.config.units.name == CONF_UNIT_SYSTEM_METRIC
-    assert hass.config.time_zone.zone == "Europe/Copenhagen"
+    assert hass.config.time_zone == "Europe/Copenhagen"
     assert len(hass.config.allowlist_external_dirs) == 3
     assert "/etc" in hass.config.allowlist_external_dirs
     assert hass.config.config_source == config_util.SOURCE_YAML
@@ -493,7 +493,7 @@ async def test_loading_configuration(hass):
     assert hass.config.elevation == 25
     assert hass.config.location_name == "Huis"
     assert hass.config.units.name == CONF_UNIT_SYSTEM_IMPERIAL
-    assert hass.config.time_zone.zone == "America/New_York"
+    assert hass.config.time_zone == "America/New_York"
     assert hass.config.external_url == "https://www.example.com"
     assert hass.config.internal_url == "http://example.local"
     assert len(hass.config.allowlist_external_dirs) == 3
@@ -525,7 +525,7 @@ async def test_loading_configuration_temperature_unit(hass):
     assert hass.config.elevation == 25
     assert hass.config.location_name == "Huis"
     assert hass.config.units.name == CONF_UNIT_SYSTEM_METRIC
-    assert hass.config.time_zone.zone == "America/New_York"
+    assert hass.config.time_zone == "America/New_York"
     assert hass.config.external_url == "https://www.example.com"
     assert hass.config.internal_url == "http://example.local"
     assert hass.config.config_source == config_util.SOURCE_YAML

tests/test_core.py

@@ -9,7 +9,6 @@ from tempfile import TemporaryDirectory
 from unittest.mock import MagicMock, Mock, PropertyMock, patch
 
 import pytest
-import pytz
 import voluptuous as vol
 
 from homeassistant.const import (
@@ -44,7 +43,7 @@ from homeassistant.util.unit_system import METRIC_SYSTEM
 
 from tests.common import async_capture_events, async_mock_service
 
-PST = pytz.timezone("America/Los_Angeles")
+PST = dt_util.get_time_zone("America/Los_Angeles")
 
 
 def test_split_entity_id():
@@ -877,7 +876,7 @@ def test_config_defaults():
     assert config.longitude == 0
     assert config.elevation == 0
     assert config.location_name == "Home"
-    assert config.time_zone == dt_util.UTC
+    assert config.time_zone == "UTC"
     assert config.internal_url is None
     assert config.external_url is None
     assert config.config_source == "default"

tests/util/test_dt.py

@@ -16,17 +16,12 @@ def teardown():
 
 def test_get_time_zone_retrieves_valid_time_zone():
     """Test getting a time zone."""
-    time_zone = dt_util.get_time_zone(TEST_TIME_ZONE)
+    assert dt_util.get_time_zone(TEST_TIME_ZONE) is not None
-
-    assert time_zone is not None
-    assert time_zone.zone == TEST_TIME_ZONE
 
 
 def test_get_time_zone_returns_none_for_garbage_time_zone():
     """Test getting a non existing time zone."""
-    time_zone = dt_util.get_time_zone("Non existing time zone")
+    assert dt_util.get_time_zone("Non existing time zone") is None
-
-    assert time_zone is None
 
 
 def test_set_default_time_zone():
@@ -35,8 +30,7 @@ def test_set_default_time_zone():
 
     dt_util.set_default_time_zone(time_zone)
 
-    # We cannot compare the timezones directly because of DST
+    assert dt_util.now().tzinfo is time_zone
-    assert time_zone.zone == dt_util.now().tzinfo.zone
 
 
 def test_utcnow():
@@ -239,35 +233,111 @@ def test_find_next_time_expression_time_dst():
         return dt_util.find_next_time_expression_time(dt, seconds, minutes, hours)
 
     # Entering DST, clocks are rolled forward
-    assert tz.localize(datetime(2018, 3, 26, 2, 30, 0)) == find(
+    assert datetime(2018, 3, 26, 2, 30, 0, tzinfo=tz) == find(
-        tz.localize(datetime(2018, 3, 25, 1, 50, 0)), 2, 30, 0
+        datetime(2018, 3, 25, 1, 50, 0, tzinfo=tz), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 3, 26, 2, 30, 0)) == find(
+    assert datetime(2018, 3, 26, 2, 30, 0, tzinfo=tz) == find(
-        tz.localize(datetime(2018, 3, 25, 3, 50, 0)), 2, 30, 0
+        datetime(2018, 3, 25, 3, 50, 0, tzinfo=tz), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 3, 26, 2, 30, 0)) == find(
+    assert datetime(2018, 3, 26, 2, 30, 0, tzinfo=tz) == find(
-        tz.localize(datetime(2018, 3, 26, 1, 50, 0)), 2, 30, 0
+        datetime(2018, 3, 26, 1, 50, 0, tzinfo=tz), 2, 30, 0
     )
 
     # Leaving DST, clocks are rolled back
-    assert tz.localize(datetime(2018, 10, 28, 2, 30, 0), is_dst=False) == find(
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=0) == find(
-        tz.localize(datetime(2018, 10, 28, 2, 5, 0), is_dst=False), 2, 30, 0
+        datetime(2018, 10, 28, 2, 5, 0, tzinfo=tz, fold=0), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 10, 28, 2, 30, 0), is_dst=False) == find(
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=0) == find(
-        tz.localize(datetime(2018, 10, 28, 2, 55, 0), is_dst=True), 2, 30, 0
+        datetime(2018, 10, 28, 2, 5, 0, tzinfo=tz), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 10, 28, 4, 30, 0), is_dst=False) == find(
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=1) == find(
-        tz.localize(datetime(2018, 10, 28, 2, 55, 0), is_dst=True), 4, 30, 0
+        datetime(2018, 10, 28, 2, 55, 0, tzinfo=tz), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 10, 28, 2, 30, 0), is_dst=True) == find(
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=1) == find(
-        tz.localize(datetime(2018, 10, 28, 2, 5, 0), is_dst=True), 2, 30, 0
+        datetime(2018, 10, 28, 2, 55, 0, tzinfo=tz, fold=0), 2, 30, 0
     )
 
-    assert tz.localize(datetime(2018, 10, 29, 2, 30, 0)) == find(
+    assert datetime(2018, 10, 28, 4, 30, 0, tzinfo=tz, fold=0) == find(
-        tz.localize(datetime(2018, 10, 28, 2, 55, 0), is_dst=False), 2, 30, 0
+        datetime(2018, 10, 28, 2, 55, 0, tzinfo=tz, fold=1), 4, 30, 0
+    )
+
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2018, 10, 28, 2, 5, 0, tzinfo=tz, fold=1), 2, 30, 0
+    )
+
+    assert datetime(2018, 10, 28, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2018, 10, 28, 2, 55, 0, tzinfo=tz, fold=0), 2, 30, 0
+    )
+
+
+def test_find_next_time_expression_time_dst_chicago():
+    """Test daylight saving time for find_next_time_expression_time."""
+    tz = dt_util.get_time_zone("America/Chicago")
+    dt_util.set_default_time_zone(tz)
+
+    def find(dt, hour, minute, second):
+        """Call test_find_next_time_expression_time."""
+        seconds = dt_util.parse_time_expression(second, 0, 59)
+        minutes = dt_util.parse_time_expression(minute, 0, 59)
+        hours = dt_util.parse_time_expression(hour, 0, 23)
+
+        return dt_util.find_next_time_expression_time(dt, seconds, minutes, hours)
+
+    # Entering DST, clocks are rolled forward
+    assert datetime(2021, 3, 15, 2, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 3, 14, 1, 50, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 3, 15, 2, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 3, 14, 3, 50, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 3, 15, 2, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 3, 14, 1, 50, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 3, 14, 3, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 3, 14, 1, 50, 0, tzinfo=tz), 3, 30, 0
+    )
+
+    # Leaving DST, clocks are rolled back
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=0) == find(
+        datetime(2021, 11, 7, 2, 5, 0, tzinfo=tz, fold=0), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 11, 7, 2, 5, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=0) == find(
+        datetime(2021, 11, 7, 2, 5, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2021, 11, 7, 2, 10, 0, tzinfo=tz), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=0), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 8, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2021, 11, 7, 2, 55, 0, tzinfo=tz, fold=0), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 4, 30, 0, tzinfo=tz, fold=0) == find(
+        datetime(2021, 11, 7, 2, 55, 0, tzinfo=tz, fold=1), 4, 30, 0
+    )
+
+    assert datetime(2021, 11, 7, 2, 30, 0, tzinfo=tz, fold=1) == find(
+        datetime(2021, 11, 7, 2, 5, 0, tzinfo=tz, fold=1), 2, 30, 0
+    )
+
+    assert datetime(2021, 11, 8, 2, 30, 0, tzinfo=tz) == find(
+        datetime(2021, 11, 7, 2, 55, 0, tzinfo=tz, fold=0), 2, 30, 0
     )