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django/tests/get_earliest_or_latest/tests.py
Nick Pope 847f46e9bf
Removed redundant QuerySet.all() calls in docs and tests.
Most QuerySet methods are mapped onto the Manager and, in general,
it isn't necessary to call .all() on the manager.
2022-02-22 10:29:38 +01:00

248 lines
9.0 KiB
Python

from datetime import datetime
from django.test import TestCase
from .models import Article, IndexErrorArticle, Person
class EarliestOrLatestTests(TestCase):
"""Tests for the earliest() and latest() objects methods"""
@classmethod
def setUpClass(cls):
super().setUpClass()
cls._article_get_latest_by = Article._meta.get_latest_by
def tearDown(self):
Article._meta.get_latest_by = self._article_get_latest_by
def test_earliest(self):
# Because no Articles exist yet, earliest() raises ArticleDoesNotExist.
with self.assertRaises(Article.DoesNotExist):
Article.objects.earliest()
a1 = Article.objects.create(
headline="Article 1",
pub_date=datetime(2005, 7, 26),
expire_date=datetime(2005, 9, 1),
)
a2 = Article.objects.create(
headline="Article 2",
pub_date=datetime(2005, 7, 27),
expire_date=datetime(2005, 7, 28),
)
a3 = Article.objects.create(
headline="Article 3",
pub_date=datetime(2005, 7, 28),
expire_date=datetime(2005, 8, 27),
)
a4 = Article.objects.create(
headline="Article 4",
pub_date=datetime(2005, 7, 28),
expire_date=datetime(2005, 7, 30),
)
# Get the earliest Article.
self.assertEqual(Article.objects.earliest(), a1)
# Get the earliest Article that matches certain filters.
self.assertEqual(
Article.objects.filter(pub_date__gt=datetime(2005, 7, 26)).earliest(), a2
)
# Pass a custom field name to earliest() to change the field that's used
# to determine the earliest object.
self.assertEqual(Article.objects.earliest("expire_date"), a2)
self.assertEqual(
Article.objects.filter(pub_date__gt=datetime(2005, 7, 26)).earliest(
"expire_date"
),
a2,
)
# earliest() overrides any other ordering specified on the query.
# Refs #11283.
self.assertEqual(Article.objects.order_by("id").earliest(), a1)
# Error is raised if the user forgot to add a get_latest_by
# in the Model.Meta
Article.objects.model._meta.get_latest_by = None
with self.assertRaisesMessage(
ValueError,
"earliest() and latest() require either fields as positional "
"arguments or 'get_latest_by' in the model's Meta.",
):
Article.objects.earliest()
# Earliest publication date, earliest expire date.
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest(
"pub_date", "expire_date"
),
a4,
)
# Earliest publication date, latest expire date.
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest(
"pub_date", "-expire_date"
),
a3,
)
# Meta.get_latest_by may be a tuple.
Article.objects.model._meta.get_latest_by = ("pub_date", "expire_date")
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 28)).earliest(), a4
)
def test_earliest_sliced_queryset(self):
msg = "Cannot change a query once a slice has been taken."
with self.assertRaisesMessage(TypeError, msg):
Article.objects.all()[0:5].earliest()
def test_latest(self):
# Because no Articles exist yet, latest() raises ArticleDoesNotExist.
with self.assertRaises(Article.DoesNotExist):
Article.objects.latest()
a1 = Article.objects.create(
headline="Article 1",
pub_date=datetime(2005, 7, 26),
expire_date=datetime(2005, 9, 1),
)
a2 = Article.objects.create(
headline="Article 2",
pub_date=datetime(2005, 7, 27),
expire_date=datetime(2005, 7, 28),
)
a3 = Article.objects.create(
headline="Article 3",
pub_date=datetime(2005, 7, 27),
expire_date=datetime(2005, 8, 27),
)
a4 = Article.objects.create(
headline="Article 4",
pub_date=datetime(2005, 7, 28),
expire_date=datetime(2005, 7, 30),
)
# Get the latest Article.
self.assertEqual(Article.objects.latest(), a4)
# Get the latest Article that matches certain filters.
self.assertEqual(
Article.objects.filter(pub_date__lt=datetime(2005, 7, 27)).latest(), a1
)
# Pass a custom field name to latest() to change the field that's used
# to determine the latest object.
self.assertEqual(Article.objects.latest("expire_date"), a1)
self.assertEqual(
Article.objects.filter(pub_date__gt=datetime(2005, 7, 26)).latest(
"expire_date"
),
a3,
)
# latest() overrides any other ordering specified on the query (#11283).
self.assertEqual(Article.objects.order_by("id").latest(), a4)
# Error is raised if get_latest_by isn't in Model.Meta.
Article.objects.model._meta.get_latest_by = None
with self.assertRaisesMessage(
ValueError,
"earliest() and latest() require either fields as positional "
"arguments or 'get_latest_by' in the model's Meta.",
):
Article.objects.latest()
# Latest publication date, latest expire date.
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest(
"pub_date", "expire_date"
),
a3,
)
# Latest publication date, earliest expire date.
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest(
"pub_date", "-expire_date"
),
a2,
)
# Meta.get_latest_by may be a tuple.
Article.objects.model._meta.get_latest_by = ("pub_date", "expire_date")
self.assertEqual(
Article.objects.filter(pub_date=datetime(2005, 7, 27)).latest(), a3
)
def test_latest_sliced_queryset(self):
msg = "Cannot change a query once a slice has been taken."
with self.assertRaisesMessage(TypeError, msg):
Article.objects.all()[0:5].latest()
def test_latest_manual(self):
# You can still use latest() with a model that doesn't have
# "get_latest_by" set -- just pass in the field name manually.
Person.objects.create(name="Ralph", birthday=datetime(1950, 1, 1))
p2 = Person.objects.create(name="Stephanie", birthday=datetime(1960, 2, 3))
msg = (
"earliest() and latest() require either fields as positional arguments "
"or 'get_latest_by' in the model's Meta."
)
with self.assertRaisesMessage(ValueError, msg):
Person.objects.latest()
self.assertEqual(Person.objects.latest("birthday"), p2)
class TestFirstLast(TestCase):
def test_first(self):
p1 = Person.objects.create(name="Bob", birthday=datetime(1950, 1, 1))
p2 = Person.objects.create(name="Alice", birthday=datetime(1961, 2, 3))
self.assertEqual(Person.objects.first(), p1)
self.assertEqual(Person.objects.order_by("name").first(), p2)
self.assertEqual(
Person.objects.filter(birthday__lte=datetime(1955, 1, 1)).first(), p1
)
self.assertIsNone(
Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).first()
)
def test_last(self):
p1 = Person.objects.create(name="Alice", birthday=datetime(1950, 1, 1))
p2 = Person.objects.create(name="Bob", birthday=datetime(1960, 2, 3))
# Note: by default PK ordering.
self.assertEqual(Person.objects.last(), p2)
self.assertEqual(Person.objects.order_by("-name").last(), p1)
self.assertEqual(
Person.objects.filter(birthday__lte=datetime(1955, 1, 1)).last(), p1
)
self.assertIsNone(
Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).last()
)
def test_index_error_not_suppressed(self):
"""
#23555 -- Unexpected IndexError exceptions in QuerySet iteration
shouldn't be suppressed.
"""
def check():
# We know that we've broken the __iter__ method, so the queryset
# should always raise an exception.
with self.assertRaises(IndexError):
IndexErrorArticle.objects.all()[:10:2]
with self.assertRaises(IndexError):
IndexErrorArticle.objects.first()
with self.assertRaises(IndexError):
IndexErrorArticle.objects.last()
check()
# And it does not matter if there are any records in the DB.
IndexErrorArticle.objects.create(
headline="Article 1",
pub_date=datetime(2005, 7, 26),
expire_date=datetime(2005, 9, 1),
)
check()