django/tests/get_earliest_or_latest/tests.py

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from __future__ import absolute_import
from datetime import datetime
from django.test import TestCase
from .models import Article, Person
class EarliestOrLatestTests(TestCase):
"""Tests for the earliest() and latest() objects methods"""
def tearDown(self):
"""Makes sure Article has a get_latest_by"""
if not Article._meta.get_latest_by:
Article._meta.get_latest_by = 'pub_date'
def test_earliest(self):
# Because no Articles exist yet, earliest() raises ArticleDoesNotExist.
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)
# Ensure that earliest() overrides any other ordering specified on the
# query. Refs #11283.
self.assertEqual(Article.objects.order_by('id').earliest(), a1)
# Ensure that 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
self.assertRaisesMessage(
AssertionError,
"earliest() and latest() require either a field_name parameter or "
"'get_latest_by' in the model",
lambda: Article.objects.earliest(),
)
def test_latest(self):
# Because no Articles exist yet, latest() raises ArticleDoesNotExist.
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,
)
# Ensure that latest() overrides any other ordering specified on the query. Refs #11283.
self.assertEqual(Article.objects.order_by('id').latest(), a4)
# Ensure that 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
self.assertRaisesMessage(
AssertionError,
"earliest() and latest() require either a field_name parameter or "
"'get_latest_by' in the model",
lambda: Article.objects.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.
p1 = Person.objects.create(name="Ralph", birthday=datetime(1950, 1, 1))
p2 = Person.objects.create(name="Stephanie", birthday=datetime(1960, 2, 3))
self.assertRaises(AssertionError, Person.objects.latest)
self.assertEqual(Person.objects.latest("birthday"), p2)
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.assertIs(
Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).first(),
None)
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.assertIs(
Person.objects.filter(birthday__lte=datetime(1940, 1, 1)).last(),
None)