import datetime
import re
import sys
from contextlib import contextmanager
from unittest import SkipTest, skipIf
from xml.dom.minidom import parseString

import pytz

try:
    import zoneinfo
except ImportError:
    try:
        from backports import zoneinfo
    except ImportError:
        zoneinfo = None

from django.contrib.auth.models import User
from django.core import serializers
from django.db import connection
from django.db.models import F, Max, Min
from django.http import HttpRequest
from django.template import (
    Context, RequestContext, Template, TemplateSyntaxError, context_processors,
)
from django.test import (
    SimpleTestCase, TestCase, TransactionTestCase, override_settings,
    skipIfDBFeature, skipUnlessDBFeature,
)
from django.test.utils import requires_tz_support
from django.urls import reverse
from django.utils import timezone
from django.utils.timezone import timedelta

from .forms import (
    EventForm, EventLocalizedForm, EventLocalizedModelForm, EventModelForm,
    EventSplitForm,
)
from .models import (
    AllDayEvent, Event, MaybeEvent, Session, SessionEvent, Timestamp,
)

try:
    import yaml
    HAS_YAML = True
except ImportError:
    HAS_YAML = False

# These tests use the EAT (Eastern Africa Time) and ICT (Indochina Time)
# who don't have Daylight Saving Time, so we can represent them easily
# with fixed offset timezones and use them directly as tzinfo in the
# constructors.

# settings.TIME_ZONE is forced to EAT. Most tests use a variant of
# datetime.datetime(2011, 9, 1, 13, 20, 30), which translates to
# 10:20:30 in UTC and 17:20:30 in ICT.

UTC = timezone.utc
EAT = timezone.get_fixed_timezone(180)      # Africa/Nairobi
ICT = timezone.get_fixed_timezone(420)      # Asia/Bangkok

ZONE_CONSTRUCTORS = (pytz.timezone,)
if zoneinfo is not None:
    ZONE_CONSTRUCTORS += (zoneinfo.ZoneInfo,)


def get_timezones(key):
    return [constructor(key) for constructor in ZONE_CONSTRUCTORS]


@contextmanager
def override_database_connection_timezone(timezone):
    try:
        orig_timezone = connection.settings_dict['TIME_ZONE']
        connection.settings_dict['TIME_ZONE'] = timezone
        # Clear cached properties, after first accessing them to ensure they exist.
        connection.timezone
        del connection.timezone
        connection.timezone_name
        del connection.timezone_name
        yield
    finally:
        connection.settings_dict['TIME_ZONE'] = orig_timezone
        # Clear cached properties, after first accessing them to ensure they exist.
        connection.timezone
        del connection.timezone
        connection.timezone_name
        del connection.timezone_name


@override_settings(TIME_ZONE='Africa/Nairobi', USE_TZ=False)
class LegacyDatabaseTests(TestCase):

    def test_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_naive_datetime_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, 405060)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_aware_datetime_in_local_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertIsNone(event.dt.tzinfo)
        # interpret the naive datetime in local time to get the correct value
        self.assertEqual(event.dt.replace(tzinfo=EAT), dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_aware_datetime_in_local_timezone_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, 405060, tzinfo=EAT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertIsNone(event.dt.tzinfo)
        # interpret the naive datetime in local time to get the correct value
        self.assertEqual(event.dt.replace(tzinfo=EAT), dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_aware_datetime_in_utc(self):
        dt = datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertIsNone(event.dt.tzinfo)
        # interpret the naive datetime in local time to get the correct value
        self.assertEqual(event.dt.replace(tzinfo=EAT), dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_aware_datetime_in_other_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=ICT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertIsNone(event.dt.tzinfo)
        # interpret the naive datetime in local time to get the correct value
        self.assertEqual(event.dt.replace(tzinfo=EAT), dt)

    @skipIfDBFeature('supports_timezones')
    def test_aware_datetime_unsupported(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        msg = 'backend does not support timezone-aware datetimes when USE_TZ is False.'
        with self.assertRaisesMessage(ValueError, msg):
            Event.objects.create(dt=dt)

    def test_auto_now_and_auto_now_add(self):
        now = datetime.datetime.now()
        past = now - datetime.timedelta(seconds=2)
        future = now + datetime.timedelta(seconds=2)
        Timestamp.objects.create()
        ts = Timestamp.objects.get()
        self.assertLess(past, ts.created)
        self.assertLess(past, ts.updated)
        self.assertGreater(future, ts.updated)
        self.assertGreater(future, ts.updated)

    def test_query_filter(self):
        dt1 = datetime.datetime(2011, 9, 1, 12, 20, 30)
        dt2 = datetime.datetime(2011, 9, 1, 14, 20, 30)
        Event.objects.create(dt=dt1)
        Event.objects.create(dt=dt2)
        self.assertEqual(Event.objects.filter(dt__gte=dt1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__gt=dt1).count(), 1)
        self.assertEqual(Event.objects.filter(dt__gte=dt2).count(), 1)
        self.assertEqual(Event.objects.filter(dt__gt=dt2).count(), 0)

    def test_query_datetime_lookups(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0))
        self.assertEqual(Event.objects.filter(dt__year=2011).count(), 2)
        self.assertEqual(Event.objects.filter(dt__month=1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__day=1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__week_day=7).count(), 2)
        self.assertEqual(Event.objects.filter(dt__iso_week_day=6).count(), 2)
        self.assertEqual(Event.objects.filter(dt__hour=1).count(), 1)
        self.assertEqual(Event.objects.filter(dt__minute=30).count(), 2)
        self.assertEqual(Event.objects.filter(dt__second=0).count(), 2)

    def test_query_aggregation(self):
        # Only min and max make sense for datetimes.
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 23, 20, 20))
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 13, 20, 30))
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 3, 20, 40))
        result = Event.objects.all().aggregate(Min('dt'), Max('dt'))
        self.assertEqual(result, {
            'dt__min': datetime.datetime(2011, 9, 1, 3, 20, 40),
            'dt__max': datetime.datetime(2011, 9, 1, 23, 20, 20),
        })

    def test_query_annotation(self):
        # Only min and max make sense for datetimes.
        morning = Session.objects.create(name='morning')
        afternoon = Session.objects.create(name='afternoon')
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 23, 20, 20), session=afternoon)
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 13, 20, 30), session=afternoon)
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 3, 20, 40), session=morning)
        morning_min_dt = datetime.datetime(2011, 9, 1, 3, 20, 40)
        afternoon_min_dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).order_by('dt'),
            [morning_min_dt, afternoon_min_dt],
            transform=lambda d: d.dt,
        )
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).filter(dt__lt=afternoon_min_dt),
            [morning_min_dt],
            transform=lambda d: d.dt,
        )
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).filter(dt__gte=afternoon_min_dt),
            [afternoon_min_dt],
            transform=lambda d: d.dt,
        )

    def test_query_datetimes(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0))
        self.assertSequenceEqual(Event.objects.datetimes('dt', 'year'), [datetime.datetime(2011, 1, 1, 0, 0, 0)])
        self.assertSequenceEqual(Event.objects.datetimes('dt', 'month'), [datetime.datetime(2011, 1, 1, 0, 0, 0)])
        self.assertSequenceEqual(Event.objects.datetimes('dt', 'day'), [datetime.datetime(2011, 1, 1, 0, 0, 0)])
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'hour'),
            [datetime.datetime(2011, 1, 1, 1, 0, 0),
             datetime.datetime(2011, 1, 1, 4, 0, 0)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'minute'),
            [datetime.datetime(2011, 1, 1, 1, 30, 0),
             datetime.datetime(2011, 1, 1, 4, 30, 0)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'second'),
            [datetime.datetime(2011, 1, 1, 1, 30, 0),
             datetime.datetime(2011, 1, 1, 4, 30, 0)]
        )

    def test_raw_sql(self):
        # Regression test for #17755
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        event = Event.objects.create(dt=dt)
        self.assertEqual(list(Event.objects.raw('SELECT * FROM timezones_event WHERE dt = %s', [dt])), [event])

    def test_cursor_execute_accepts_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        with connection.cursor() as cursor:
            cursor.execute('INSERT INTO timezones_event (dt) VALUES (%s)', [dt])
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_cursor_execute_returns_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        Event.objects.create(dt=dt)
        with connection.cursor() as cursor:
            cursor.execute('SELECT dt FROM timezones_event WHERE dt = %s', [dt])
            self.assertEqual(cursor.fetchall()[0][0], dt)

    def test_filter_date_field_with_aware_datetime(self):
        # Regression test for #17742
        day = datetime.date(2011, 9, 1)
        AllDayEvent.objects.create(day=day)
        # This is 2011-09-02T01:30:00+03:00 in EAT
        dt = datetime.datetime(2011, 9, 1, 22, 30, 0, tzinfo=UTC)
        self.assertTrue(AllDayEvent.objects.filter(day__gte=dt).exists())


@override_settings(TIME_ZONE='Africa/Nairobi', USE_TZ=True)
class NewDatabaseTests(TestCase):
    naive_warning = 'DateTimeField Event.dt received a naive datetime'

    @requires_tz_support
    def test_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            Event.objects.create(dt=dt)
        event = Event.objects.get()
        # naive datetimes are interpreted in local time
        self.assertEqual(event.dt, dt.replace(tzinfo=EAT))

    @requires_tz_support
    def test_datetime_from_date(self):
        dt = datetime.date(2011, 9, 1)
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, datetime.datetime(2011, 9, 1, tzinfo=EAT))

    @requires_tz_support
    def test_naive_datetime_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, 405060)
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            Event.objects.create(dt=dt)
        event = Event.objects.get()
        # naive datetimes are interpreted in local time
        self.assertEqual(event.dt, dt.replace(tzinfo=EAT))

    def test_aware_datetime_in_local_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_aware_datetime_in_local_timezone_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, 405060, tzinfo=EAT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_aware_datetime_in_utc(self):
        dt = datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_aware_datetime_in_other_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=ICT)
        Event.objects.create(dt=dt)
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    def test_auto_now_and_auto_now_add(self):
        now = timezone.now()
        past = now - datetime.timedelta(seconds=2)
        future = now + datetime.timedelta(seconds=2)
        Timestamp.objects.create()
        ts = Timestamp.objects.get()
        self.assertLess(past, ts.created)
        self.assertLess(past, ts.updated)
        self.assertGreater(future, ts.updated)
        self.assertGreater(future, ts.updated)

    def test_query_filter(self):
        dt1 = datetime.datetime(2011, 9, 1, 12, 20, 30, tzinfo=EAT)
        dt2 = datetime.datetime(2011, 9, 1, 14, 20, 30, tzinfo=EAT)
        Event.objects.create(dt=dt1)
        Event.objects.create(dt=dt2)
        self.assertEqual(Event.objects.filter(dt__gte=dt1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__gt=dt1).count(), 1)
        self.assertEqual(Event.objects.filter(dt__gte=dt2).count(), 1)
        self.assertEqual(Event.objects.filter(dt__gt=dt2).count(), 0)

    def test_query_filter_with_pytz_timezones(self):
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                dt = datetime.datetime(2011, 9, 1, 12, 20, 30, tzinfo=tz)
                Event.objects.create(dt=dt)
                next = dt + datetime.timedelta(seconds=3)
                prev = dt - datetime.timedelta(seconds=3)
                self.assertEqual(Event.objects.filter(dt__exact=dt).count(), 1)
                self.assertEqual(Event.objects.filter(dt__exact=next).count(), 0)
                self.assertEqual(Event.objects.filter(dt__in=(prev, next)).count(), 0)
                self.assertEqual(Event.objects.filter(dt__in=(prev, dt, next)).count(), 1)
                self.assertEqual(Event.objects.filter(dt__range=(prev, next)).count(), 1)

    def test_query_convert_timezones(self):
        # Connection timezone is equal to the current timezone, datetime
        # shouldn't be converted.
        with override_database_connection_timezone('Africa/Nairobi'):
            event_datetime = datetime.datetime(2016, 1, 2, 23, 10, 11, 123, tzinfo=EAT)
            event = Event.objects.create(dt=event_datetime)
            self.assertEqual(Event.objects.filter(dt__date=event_datetime.date()).first(), event)
        # Connection timezone is not equal to the current timezone, datetime
        # should be converted (-4h).
        with override_database_connection_timezone('Asia/Bangkok'):
            event_datetime = datetime.datetime(2016, 1, 2, 3, 10, 11, tzinfo=ICT)
            event = Event.objects.create(dt=event_datetime)
            self.assertEqual(Event.objects.filter(dt__date=datetime.date(2016, 1, 1)).first(), event)

    @requires_tz_support
    def test_query_filter_with_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 12, 20, 30, tzinfo=EAT)
        Event.objects.create(dt=dt)
        dt = dt.replace(tzinfo=None)
        # naive datetimes are interpreted in local time
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            self.assertEqual(Event.objects.filter(dt__exact=dt).count(), 1)
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            self.assertEqual(Event.objects.filter(dt__lte=dt).count(), 1)
        with self.assertWarnsMessage(RuntimeWarning, self.naive_warning):
            self.assertEqual(Event.objects.filter(dt__gt=dt).count(), 0)

    @skipUnlessDBFeature('has_zoneinfo_database')
    def test_query_datetime_lookups(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT))
        self.assertEqual(Event.objects.filter(dt__year=2011).count(), 2)
        self.assertEqual(Event.objects.filter(dt__month=1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__day=1).count(), 2)
        self.assertEqual(Event.objects.filter(dt__week_day=7).count(), 2)
        self.assertEqual(Event.objects.filter(dt__iso_week_day=6).count(), 2)
        self.assertEqual(Event.objects.filter(dt__hour=1).count(), 1)
        self.assertEqual(Event.objects.filter(dt__minute=30).count(), 2)
        self.assertEqual(Event.objects.filter(dt__second=0).count(), 2)

    @skipUnlessDBFeature('has_zoneinfo_database')
    def test_query_datetime_lookups_in_other_timezone(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT))
        with timezone.override(UTC):
            # These two dates fall in the same day in EAT, but in different days,
            # years and months in UTC.
            self.assertEqual(Event.objects.filter(dt__year=2011).count(), 1)
            self.assertEqual(Event.objects.filter(dt__month=1).count(), 1)
            self.assertEqual(Event.objects.filter(dt__day=1).count(), 1)
            self.assertEqual(Event.objects.filter(dt__week_day=7).count(), 1)
            self.assertEqual(Event.objects.filter(dt__iso_week_day=6).count(), 1)
            self.assertEqual(Event.objects.filter(dt__hour=22).count(), 1)
            self.assertEqual(Event.objects.filter(dt__minute=30).count(), 2)
            self.assertEqual(Event.objects.filter(dt__second=0).count(), 2)

    def test_query_aggregation(self):
        # Only min and max make sense for datetimes.
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 23, 20, 20, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 9, 1, 3, 20, 40, tzinfo=EAT))
        result = Event.objects.all().aggregate(Min('dt'), Max('dt'))
        self.assertEqual(result, {
            'dt__min': datetime.datetime(2011, 9, 1, 3, 20, 40, tzinfo=EAT),
            'dt__max': datetime.datetime(2011, 9, 1, 23, 20, 20, tzinfo=EAT),
        })

    def test_query_annotation(self):
        # Only min and max make sense for datetimes.
        morning = Session.objects.create(name='morning')
        afternoon = Session.objects.create(name='afternoon')
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 23, 20, 20, tzinfo=EAT), session=afternoon)
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT), session=afternoon)
        SessionEvent.objects.create(dt=datetime.datetime(2011, 9, 1, 3, 20, 40, tzinfo=EAT), session=morning)
        morning_min_dt = datetime.datetime(2011, 9, 1, 3, 20, 40, tzinfo=EAT)
        afternoon_min_dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).order_by('dt'),
            [morning_min_dt, afternoon_min_dt],
            transform=lambda d: d.dt,
        )
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).filter(dt__lt=afternoon_min_dt),
            [morning_min_dt],
            transform=lambda d: d.dt,
        )
        self.assertQuerysetEqual(
            Session.objects.annotate(dt=Min('events__dt')).filter(dt__gte=afternoon_min_dt),
            [afternoon_min_dt],
            transform=lambda d: d.dt,
        )

    @skipUnlessDBFeature('has_zoneinfo_database')
    def test_query_datetimes(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT))
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'year'),
            [datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=EAT)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'month'),
            [datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=EAT)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'day'),
            [datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=EAT)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'hour'),
            [datetime.datetime(2011, 1, 1, 1, 0, 0, tzinfo=EAT),
             datetime.datetime(2011, 1, 1, 4, 0, 0, tzinfo=EAT)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'minute'),
            [datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT),
             datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT)]
        )
        self.assertSequenceEqual(
            Event.objects.datetimes('dt', 'second'),
            [datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT),
             datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT)]
        )

    @skipUnlessDBFeature('has_zoneinfo_database')
    def test_query_datetimes_in_other_timezone(self):
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=EAT))
        Event.objects.create(dt=datetime.datetime(2011, 1, 1, 4, 30, 0, tzinfo=EAT))
        with timezone.override(UTC):
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'year'),
                [datetime.datetime(2010, 1, 1, 0, 0, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=UTC)]
            )
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'month'),
                [datetime.datetime(2010, 12, 1, 0, 0, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=UTC)]
            )
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'day'),
                [datetime.datetime(2010, 12, 31, 0, 0, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 0, 0, 0, tzinfo=UTC)]
            )
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'hour'),
                [datetime.datetime(2010, 12, 31, 22, 0, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 1, 0, 0, tzinfo=UTC)]
            )
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'minute'),
                [datetime.datetime(2010, 12, 31, 22, 30, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=UTC)]
            )
            self.assertSequenceEqual(
                Event.objects.datetimes('dt', 'second'),
                [datetime.datetime(2010, 12, 31, 22, 30, 0, tzinfo=UTC),
                 datetime.datetime(2011, 1, 1, 1, 30, 0, tzinfo=UTC)]
            )

    def test_raw_sql(self):
        # Regression test for #17755
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        event = Event.objects.create(dt=dt)
        self.assertSequenceEqual(list(Event.objects.raw('SELECT * FROM timezones_event WHERE dt = %s', [dt])), [event])

    @skipUnlessDBFeature('supports_timezones')
    def test_cursor_execute_accepts_aware_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        with connection.cursor() as cursor:
            cursor.execute('INSERT INTO timezones_event (dt) VALUES (%s)', [dt])
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    @skipIfDBFeature('supports_timezones')
    def test_cursor_execute_accepts_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        utc_naive_dt = timezone.make_naive(dt, timezone.utc)
        with connection.cursor() as cursor:
            cursor.execute('INSERT INTO timezones_event (dt) VALUES (%s)', [utc_naive_dt])
        event = Event.objects.get()
        self.assertEqual(event.dt, dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_cursor_execute_returns_aware_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        Event.objects.create(dt=dt)
        with connection.cursor() as cursor:
            cursor.execute('SELECT dt FROM timezones_event WHERE dt = %s', [dt])
            self.assertEqual(cursor.fetchall()[0][0], dt)

    @skipIfDBFeature('supports_timezones')
    def test_cursor_execute_returns_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)
        utc_naive_dt = timezone.make_naive(dt, timezone.utc)
        Event.objects.create(dt=dt)
        with connection.cursor() as cursor:
            cursor.execute('SELECT dt FROM timezones_event WHERE dt = %s', [utc_naive_dt])
            self.assertEqual(cursor.fetchall()[0][0], utc_naive_dt)

    @skipUnlessDBFeature('supports_timezones')
    def test_cursor_explicit_time_zone(self):
        with override_database_connection_timezone('Europe/Paris'):
            with connection.cursor() as cursor:
                cursor.execute('SELECT CURRENT_TIMESTAMP')
                now = cursor.fetchone()[0]
                self.assertEqual(str(now.tzinfo), 'Europe/Paris')

    @requires_tz_support
    def test_filter_date_field_with_aware_datetime(self):
        # Regression test for #17742
        day = datetime.date(2011, 9, 1)
        AllDayEvent.objects.create(day=day)
        # This is 2011-09-02T01:30:00+03:00 in EAT
        dt = datetime.datetime(2011, 9, 1, 22, 30, 0, tzinfo=UTC)
        self.assertFalse(AllDayEvent.objects.filter(day__gte=dt).exists())

    def test_null_datetime(self):
        # Regression test for #17294
        e = MaybeEvent.objects.create()
        self.assertIsNone(e.dt)

    def test_update_with_timedelta(self):
        initial_dt = timezone.now().replace(microsecond=0)
        event = Event.objects.create(dt=initial_dt)
        Event.objects.update(dt=F('dt') + timedelta(hours=2))
        event.refresh_from_db()
        self.assertEqual(event.dt, initial_dt + timedelta(hours=2))


@override_settings(TIME_ZONE='Africa/Nairobi', USE_TZ=True)
class ForcedTimeZoneDatabaseTests(TransactionTestCase):
    """
    Test the TIME_ZONE database configuration parameter.

    Since this involves reading and writing to the same database through two
    connections, this is a TransactionTestCase.
    """

    available_apps = ['timezones']

    @classmethod
    def setUpClass(cls):
        # @skipIfDBFeature and @skipUnlessDBFeature cannot be chained. The
        # outermost takes precedence. Handle skipping manually instead.
        if connection.features.supports_timezones:
            raise SkipTest("Database has feature(s) supports_timezones")
        if not connection.features.test_db_allows_multiple_connections:
            raise SkipTest("Database doesn't support feature(s): test_db_allows_multiple_connections")

        super().setUpClass()

    def test_read_datetime(self):
        fake_dt = datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=UTC)
        Event.objects.create(dt=fake_dt)

        with override_database_connection_timezone('Asia/Bangkok'):
            event = Event.objects.get()
            dt = datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC)
        self.assertEqual(event.dt, dt)

    def test_write_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC)
        with override_database_connection_timezone('Asia/Bangkok'):
            Event.objects.create(dt=dt)

        event = Event.objects.get()
        fake_dt = datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=UTC)
        self.assertEqual(event.dt, fake_dt)


@override_settings(TIME_ZONE='Africa/Nairobi')
class SerializationTests(SimpleTestCase):

    # Backend-specific notes:
    # - JSON supports only milliseconds, microseconds will be truncated.
    # - PyYAML dumps the UTC offset correctly for timezone-aware datetimes.
    #   When PyYAML < 5.3 loads this representation, it subtracts the offset
    #   and returns a naive datetime object in UTC. PyYAML 5.3+ loads timezones
    #   correctly.
    # Tests are adapted to take these quirks into account.

    def assert_python_contains_datetime(self, objects, dt):
        self.assertEqual(objects[0]['fields']['dt'], dt)

    def assert_json_contains_datetime(self, json, dt):
        self.assertIn('"fields": {"dt": "%s"}' % dt, json)

    def assert_xml_contains_datetime(self, xml, dt):
        field = parseString(xml).getElementsByTagName('field')[0]
        self.assertXMLEqual(field.childNodes[0].wholeText, dt)

    def assert_yaml_contains_datetime(self, yaml, dt):
        # Depending on the yaml dumper, '!timestamp' might be absent
        self.assertRegex(yaml, r"\n  fields: {dt: !(!timestamp)? '%s'}" % re.escape(dt))

    def test_naive_datetime(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T13:20:30")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T13:20:30")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 13:20:30")
            obj = next(serializers.deserialize('yaml', data)).object
            self.assertEqual(obj.dt, dt)

    def test_naive_datetime_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, 405060)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T13:20:30.405")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt.replace(microsecond=405000))

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T13:20:30.405060")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 13:20:30.405060")
            obj = next(serializers.deserialize('yaml', data)).object
            self.assertEqual(obj.dt, dt)

    def test_aware_datetime_with_microsecond(self):
        dt = datetime.datetime(2011, 9, 1, 17, 20, 30, 405060, tzinfo=ICT)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T17:20:30.405+07:00")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt.replace(microsecond=405000))

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T17:20:30.405060+07:00")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 17:20:30.405060+07:00")
            obj = next(serializers.deserialize('yaml', data)).object
            if HAS_YAML and yaml.__version__ < '5.3':
                self.assertEqual(obj.dt.replace(tzinfo=UTC), dt)
            else:
                self.assertEqual(obj.dt, dt)

    def test_aware_datetime_in_utc(self):
        dt = datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T10:20:30Z")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T10:20:30+00:00")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 10:20:30+00:00")
            obj = next(serializers.deserialize('yaml', data)).object
            self.assertEqual(obj.dt.replace(tzinfo=UTC), dt)

    def test_aware_datetime_in_local_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T13:20:30+03:00")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T13:20:30+03:00")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 13:20:30+03:00")
            obj = next(serializers.deserialize('yaml', data)).object
            if HAS_YAML and yaml.__version__ < '5.3':
                self.assertEqual(obj.dt.replace(tzinfo=UTC), dt)
            else:
                self.assertEqual(obj.dt, dt)

    def test_aware_datetime_in_other_timezone(self):
        dt = datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=ICT)

        data = serializers.serialize('python', [Event(dt=dt)])
        self.assert_python_contains_datetime(data, dt)
        obj = next(serializers.deserialize('python', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('json', [Event(dt=dt)])
        self.assert_json_contains_datetime(data, "2011-09-01T17:20:30+07:00")
        obj = next(serializers.deserialize('json', data)).object
        self.assertEqual(obj.dt, dt)

        data = serializers.serialize('xml', [Event(dt=dt)])
        self.assert_xml_contains_datetime(data, "2011-09-01T17:20:30+07:00")
        obj = next(serializers.deserialize('xml', data)).object
        self.assertEqual(obj.dt, dt)

        if not isinstance(serializers.get_serializer('yaml'), serializers.BadSerializer):
            data = serializers.serialize('yaml', [Event(dt=dt)], default_flow_style=None)
            self.assert_yaml_contains_datetime(data, "2011-09-01 17:20:30+07:00")
            obj = next(serializers.deserialize('yaml', data)).object
            if HAS_YAML and yaml.__version__ < '5.3':
                self.assertEqual(obj.dt.replace(tzinfo=UTC), dt)
            else:
                self.assertEqual(obj.dt, dt)


@override_settings(DATETIME_FORMAT='c', TIME_ZONE='Africa/Nairobi', USE_L10N=False, USE_TZ=True)
class TemplateTests(SimpleTestCase):

    @requires_tz_support
    def test_localtime_templatetag_and_filters(self):
        """
        Test the {% localtime %} templatetag and related filters.
        """
        datetimes = {
            'utc': datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC),
            'eat': datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT),
            'ict': datetime.datetime(2011, 9, 1, 17, 20, 30, tzinfo=ICT),
            'naive': datetime.datetime(2011, 9, 1, 13, 20, 30),
        }
        templates = {
            'notag': Template("{% load tz %}{{ dt }}|{{ dt|localtime }}|{{ dt|utc }}|{{ dt|timezone:ICT }}"),
            'noarg': Template(
                "{% load tz %}{% localtime %}{{ dt }}|{{ dt|localtime }}|"
                "{{ dt|utc }}|{{ dt|timezone:ICT }}{% endlocaltime %}"
            ),
            'on': Template(
                "{% load tz %}{% localtime on %}{{ dt }}|{{ dt|localtime }}|"
                "{{ dt|utc }}|{{ dt|timezone:ICT }}{% endlocaltime %}"
            ),
            'off': Template(
                "{% load tz %}{% localtime off %}{{ dt }}|{{ dt|localtime }}|"
                "{{ dt|utc }}|{{ dt|timezone:ICT }}{% endlocaltime %}"
            ),
        }

        # Transform a list of keys in 'datetimes' to the expected template
        # output. This makes the definition of 'results' more readable.
        def t(*result):
            return '|'.join(datetimes[key].isoformat() for key in result)

        # Results for USE_TZ = True

        results = {
            'utc': {
                'notag': t('eat', 'eat', 'utc', 'ict'),
                'noarg': t('eat', 'eat', 'utc', 'ict'),
                'on': t('eat', 'eat', 'utc', 'ict'),
                'off': t('utc', 'eat', 'utc', 'ict'),
            },
            'eat': {
                'notag': t('eat', 'eat', 'utc', 'ict'),
                'noarg': t('eat', 'eat', 'utc', 'ict'),
                'on': t('eat', 'eat', 'utc', 'ict'),
                'off': t('eat', 'eat', 'utc', 'ict'),
            },
            'ict': {
                'notag': t('eat', 'eat', 'utc', 'ict'),
                'noarg': t('eat', 'eat', 'utc', 'ict'),
                'on': t('eat', 'eat', 'utc', 'ict'),
                'off': t('ict', 'eat', 'utc', 'ict'),
            },
            'naive': {
                'notag': t('naive', 'eat', 'utc', 'ict'),
                'noarg': t('naive', 'eat', 'utc', 'ict'),
                'on': t('naive', 'eat', 'utc', 'ict'),
                'off': t('naive', 'eat', 'utc', 'ict'),
            }
        }

        for k1, dt in datetimes.items():
            for k2, tpl in templates.items():
                ctx = Context({'dt': dt, 'ICT': ICT})
                actual = tpl.render(ctx)
                expected = results[k1][k2]
                self.assertEqual(actual, expected, '%s / %s: %r != %r' % (k1, k2, actual, expected))

        # Changes for USE_TZ = False

        results['utc']['notag'] = t('utc', 'eat', 'utc', 'ict')
        results['ict']['notag'] = t('ict', 'eat', 'utc', 'ict')

        with self.settings(USE_TZ=False):
            for k1, dt in datetimes.items():
                for k2, tpl in templates.items():
                    ctx = Context({'dt': dt, 'ICT': ICT})
                    actual = tpl.render(ctx)
                    expected = results[k1][k2]
                    self.assertEqual(actual, expected, '%s / %s: %r != %r' % (k1, k2, actual, expected))

    def test_localtime_filters_with_iana(self):
        """
        Test the |localtime, |utc, and |timezone filters with iana zones.
        """
        # Use an IANA timezone as local time
        tpl = Template("{% load tz %}{{ dt|localtime }}|{{ dt|utc }}")
        ctx = Context({'dt': datetime.datetime(2011, 9, 1, 12, 20, 30)})

        with self.settings(TIME_ZONE='Europe/Paris'):
            self.assertEqual(tpl.render(ctx), "2011-09-01T12:20:30+02:00|2011-09-01T10:20:30+00:00")

        # Use an IANA timezone as argument
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                tpl = Template("{% load tz %}{{ dt|timezone:tz }}")
                ctx = Context({
                    'dt': datetime.datetime(2011, 9, 1, 13, 20, 30),
                    'tz': pytz.timezone('Europe/Paris'),
                })
                self.assertEqual(tpl.render(ctx), "2011-09-01T12:20:30+02:00")

    def test_localtime_templatetag_invalid_argument(self):
        with self.assertRaises(TemplateSyntaxError):
            Template("{% load tz %}{% localtime foo %}{% endlocaltime %}").render()

    def test_localtime_filters_do_not_raise_exceptions(self):
        """
        Test the |localtime, |utc, and |timezone filters on bad inputs.
        """
        tpl = Template("{% load tz %}{{ dt }}|{{ dt|localtime }}|{{ dt|utc }}|{{ dt|timezone:tz }}")
        with self.settings(USE_TZ=True):
            # bad datetime value
            ctx = Context({'dt': None, 'tz': ICT})
            self.assertEqual(tpl.render(ctx), "None|||")
            ctx = Context({'dt': 'not a date', 'tz': ICT})
            self.assertEqual(tpl.render(ctx), "not a date|||")
            # bad timezone value
            tpl = Template("{% load tz %}{{ dt|timezone:tz }}")
            ctx = Context({'dt': datetime.datetime(2011, 9, 1, 13, 20, 30), 'tz': None})
            self.assertEqual(tpl.render(ctx), "")
            ctx = Context({'dt': datetime.datetime(2011, 9, 1, 13, 20, 30), 'tz': 'not a tz'})
            self.assertEqual(tpl.render(ctx), "")

    @requires_tz_support
    def test_timezone_templatetag(self):
        """
        Test the {% timezone %} templatetag.
        """
        tpl = Template(
            "{% load tz %}"
            "{{ dt }}|"
            "{% timezone tz1 %}"
            "{{ dt }}|"
            "{% timezone tz2 %}"
            "{{ dt }}"
            "{% endtimezone %}"
            "{% endtimezone %}"
        )
        ctx = Context({
            'dt': datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC),
            'tz1': ICT,
            'tz2': None,
        })
        self.assertEqual(
            tpl.render(ctx),
            "2011-09-01T13:20:30+03:00|2011-09-01T17:20:30+07:00|2011-09-01T13:20:30+03:00"
        )

    def test_timezone_templatetag_with_iana(self):
        """
        Test the {% timezone %} templatetag with IANA time zone providers.
        """
        tpl = Template("{% load tz %}{% timezone tz %}{{ dt }}{% endtimezone %}")

        # Use a IANA timezone as argument
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                ctx = Context({
                    'dt': datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT),
                    'tz': tz,
                })
                self.assertEqual(tpl.render(ctx), "2011-09-01T12:20:30+02:00")

        # Use a IANA timezone name as argument
        ctx = Context({
            'dt': datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT),
            'tz': 'Europe/Paris',
        })
        self.assertEqual(tpl.render(ctx), "2011-09-01T12:20:30+02:00")

    def test_timezone_templatetag_invalid_argument(self):
        with self.assertRaises(TemplateSyntaxError):
            Template("{% load tz %}{% timezone %}{% endtimezone %}").render()
        with self.assertRaises(pytz.UnknownTimeZoneError):
            Template("{% load tz %}{% timezone tz %}{% endtimezone %}").render(Context({'tz': 'foobar'}))

    @skipIf(sys.platform == 'win32', "Windows uses non-standard time zone names")
    def test_get_current_timezone_templatetag(self):
        """
        Test the {% get_current_timezone %} templatetag.
        """
        tpl = Template("{% load tz %}{% get_current_timezone as time_zone %}{{ time_zone }}")

        self.assertEqual(tpl.render(Context()), "Africa/Nairobi")
        with timezone.override(UTC):
            self.assertEqual(tpl.render(Context()), "UTC")

        tpl = Template(
            "{% load tz %}{% timezone tz %}{% get_current_timezone as time_zone %}"
            "{% endtimezone %}{{ time_zone }}"
        )

        self.assertEqual(tpl.render(Context({'tz': ICT})), "+0700")
        with timezone.override(UTC):
            self.assertEqual(tpl.render(Context({'tz': ICT})), "+0700")

    def test_get_current_timezone_templatetag_with_iana(self):
        """
        Test the {% get_current_timezone %} templatetag with pytz.
        """
        tpl = Template("{% load tz %}{% get_current_timezone as time_zone %}{{ time_zone }}")
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                with timezone.override(tz):
                    self.assertEqual(tpl.render(Context()), "Europe/Paris")

        tpl = Template(
            "{% load tz %}{% timezone 'Europe/Paris' %}"
            "{% get_current_timezone as time_zone %}{% endtimezone %}"
            "{{ time_zone }}"
        )
        self.assertEqual(tpl.render(Context()), "Europe/Paris")

    def test_get_current_timezone_templatetag_invalid_argument(self):
        msg = "'get_current_timezone' requires 'as variable' (got ['get_current_timezone'])"
        with self.assertRaisesMessage(TemplateSyntaxError, msg):
            Template("{% load tz %}{% get_current_timezone %}").render()

    @skipIf(sys.platform == 'win32', "Windows uses non-standard time zone names")
    def test_tz_template_context_processor(self):
        """
        Test the django.template.context_processors.tz template context processor.
        """
        tpl = Template("{{ TIME_ZONE }}")
        context = Context()
        self.assertEqual(tpl.render(context), "")
        request_context = RequestContext(HttpRequest(), processors=[context_processors.tz])
        self.assertEqual(tpl.render(request_context), "Africa/Nairobi")

    @requires_tz_support
    def test_date_and_time_template_filters(self):
        tpl = Template("{{ dt|date:'Y-m-d' }} at {{ dt|time:'H:i:s' }}")
        ctx = Context({'dt': datetime.datetime(2011, 9, 1, 20, 20, 20, tzinfo=UTC)})
        self.assertEqual(tpl.render(ctx), "2011-09-01 at 23:20:20")
        with timezone.override(ICT):
            self.assertEqual(tpl.render(ctx), "2011-09-02 at 03:20:20")

    def test_date_and_time_template_filters_honor_localtime(self):
        tpl = Template(
            "{% load tz %}{% localtime off %}{{ dt|date:'Y-m-d' }} at "
            "{{ dt|time:'H:i:s' }}{% endlocaltime %}"
        )
        ctx = Context({'dt': datetime.datetime(2011, 9, 1, 20, 20, 20, tzinfo=UTC)})
        self.assertEqual(tpl.render(ctx), "2011-09-01 at 20:20:20")
        with timezone.override(ICT):
            self.assertEqual(tpl.render(ctx), "2011-09-01 at 20:20:20")

    @requires_tz_support
    def test_now_template_tag_uses_current_time_zone(self):
        # Regression for #17343
        tpl = Template("{% now \"O\" %}")
        self.assertEqual(tpl.render(Context({})), "+0300")
        with timezone.override(ICT):
            self.assertEqual(tpl.render(Context({})), "+0700")


@override_settings(DATETIME_FORMAT='c', TIME_ZONE='Africa/Nairobi', USE_L10N=False, USE_TZ=False)
class LegacyFormsTests(TestCase):

    def test_form(self):
        form = EventForm({'dt': '2011-09-01 13:20:30'})
        self.assertTrue(form.is_valid())
        self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 9, 1, 13, 20, 30))

    def test_form_with_non_existent_time(self):
        form = EventForm({'dt': '2011-03-27 02:30:00'})
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                with timezone.override(tz):
                    # This is a bug.
                    self.assertTrue(form.is_valid())
                    self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 3, 27, 2, 30, 0))

    def test_form_with_ambiguous_time(self):
        form = EventForm({'dt': '2011-10-30 02:30:00'})
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                with timezone.override(tz):
                    # This is a bug.
                    self.assertTrue(form.is_valid())
                    self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 10, 30, 2, 30, 0))

    def test_split_form(self):
        form = EventSplitForm({'dt_0': '2011-09-01', 'dt_1': '13:20:30'})
        self.assertTrue(form.is_valid())
        self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 9, 1, 13, 20, 30))

    def test_model_form(self):
        EventModelForm({'dt': '2011-09-01 13:20:30'}).save()
        e = Event.objects.get()
        self.assertEqual(e.dt, datetime.datetime(2011, 9, 1, 13, 20, 30))


@override_settings(DATETIME_FORMAT='c', TIME_ZONE='Africa/Nairobi', USE_L10N=False, USE_TZ=True)
class NewFormsTests(TestCase):

    @requires_tz_support
    def test_form(self):
        form = EventForm({'dt': '2011-09-01 13:20:30'})
        self.assertTrue(form.is_valid())
        self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))

    def test_form_with_other_timezone(self):
        form = EventForm({'dt': '2011-09-01 17:20:30'})
        with timezone.override(ICT):
            self.assertTrue(form.is_valid())
            self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))

    def test_form_with_non_existent_time(self):
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                with timezone.override(tz):
                    form = EventForm({'dt': '2011-03-27 02:30:00'})
                    self.assertFalse(form.is_valid())
                    self.assertEqual(
                        form.errors['dt'], [
                            '2011-03-27 02:30:00 couldn’t be interpreted in time zone '
                            'Europe/Paris; it may be ambiguous or it may not exist.'
                        ]
                    )

    def test_form_with_ambiguous_time(self):
        for tz in get_timezones('Europe/Paris'):
            with self.subTest(repr(tz)):
                with timezone.override(tz):
                    form = EventForm({'dt': '2011-10-30 02:30:00'})
                    self.assertFalse(form.is_valid())
                    self.assertEqual(
                        form.errors['dt'], [
                            '2011-10-30 02:30:00 couldn’t be interpreted in time zone '
                            'Europe/Paris; it may be ambiguous or it may not exist.'
                        ]
                    )

    @requires_tz_support
    def test_split_form(self):
        form = EventSplitForm({'dt_0': '2011-09-01', 'dt_1': '13:20:30'})
        self.assertTrue(form.is_valid())
        self.assertEqual(form.cleaned_data['dt'], datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))

    @requires_tz_support
    def test_localized_form(self):
        form = EventLocalizedForm(initial={'dt': datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)})
        with timezone.override(ICT):
            self.assertIn("2011-09-01 17:20:30", str(form))

    @requires_tz_support
    def test_model_form(self):
        EventModelForm({'dt': '2011-09-01 13:20:30'}).save()
        e = Event.objects.get()
        self.assertEqual(e.dt, datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))

    @requires_tz_support
    def test_localized_model_form(self):
        form = EventLocalizedModelForm(instance=Event(dt=datetime.datetime(2011, 9, 1, 13, 20, 30, tzinfo=EAT)))
        with timezone.override(ICT):
            self.assertIn("2011-09-01 17:20:30", str(form))


@override_settings(
    DATETIME_FORMAT='c',
    TIME_ZONE='Africa/Nairobi',
    USE_L10N=False,
    USE_TZ=True,
    ROOT_URLCONF='timezones.urls',
)
class AdminTests(TestCase):

    @classmethod
    def setUpTestData(cls):
        cls.u1 = User.objects.create_user(
            password='secret',
            last_login=datetime.datetime(2007, 5, 30, 13, 20, 10, tzinfo=UTC),
            is_superuser=True, username='super', first_name='Super', last_name='User',
            email='super@example.com', is_staff=True, is_active=True,
            date_joined=datetime.datetime(2007, 5, 30, 13, 20, 10, tzinfo=UTC),
        )

    def setUp(self):
        self.client.force_login(self.u1)

    @requires_tz_support
    def test_changelist(self):
        e = Event.objects.create(dt=datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))
        response = self.client.get(reverse('admin_tz:timezones_event_changelist'))
        self.assertContains(response, e.dt.astimezone(EAT).isoformat())

    def test_changelist_in_other_timezone(self):
        e = Event.objects.create(dt=datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))
        with timezone.override(ICT):
            response = self.client.get(reverse('admin_tz:timezones_event_changelist'))
        self.assertContains(response, e.dt.astimezone(ICT).isoformat())

    @requires_tz_support
    def test_change_editable(self):
        e = Event.objects.create(dt=datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))
        response = self.client.get(reverse('admin_tz:timezones_event_change', args=(e.pk,)))
        self.assertContains(response, e.dt.astimezone(EAT).date().isoformat())
        self.assertContains(response, e.dt.astimezone(EAT).time().isoformat())

    def test_change_editable_in_other_timezone(self):
        e = Event.objects.create(dt=datetime.datetime(2011, 9, 1, 10, 20, 30, tzinfo=UTC))
        with timezone.override(ICT):
            response = self.client.get(reverse('admin_tz:timezones_event_change', args=(e.pk,)))
        self.assertContains(response, e.dt.astimezone(ICT).date().isoformat())
        self.assertContains(response, e.dt.astimezone(ICT).time().isoformat())

    @requires_tz_support
    def test_change_readonly(self):
        Timestamp.objects.create()
        # re-fetch the object for backends that lose microseconds (MySQL)
        t = Timestamp.objects.get()
        response = self.client.get(reverse('admin_tz:timezones_timestamp_change', args=(t.pk,)))
        self.assertContains(response, t.created.astimezone(EAT).isoformat())

    def test_change_readonly_in_other_timezone(self):
        Timestamp.objects.create()
        # re-fetch the object for backends that lose microseconds (MySQL)
        t = Timestamp.objects.get()
        with timezone.override(ICT):
            response = self.client.get(reverse('admin_tz:timezones_timestamp_change', args=(t.pk,)))
        self.assertContains(response, t.created.astimezone(ICT).isoformat())
