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e542e81b39
The old names were downright confusing. Some seemed to mean the opposite
of what the class actually did.
The new names follow a consistent nomenclature:
(Forward|Reverse)(ManyToOne|OneToOne|ManyToMany)Descriptor.
I mentioned combinations that do not exist in the docstring in order to
help people who would search for them in the code base.
141 lines
6.3 KiB
Python
141 lines
6.3 KiB
Python
from __future__ import unicode_literals
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from django.test import TestCase
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from .models import Article, Car, Driver, Reporter
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class ManyToOneNullTests(TestCase):
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def setUp(self):
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# Create a Reporter.
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self.r = Reporter(name='John Smith')
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self.r.save()
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# Create an Article.
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self.a = Article(headline="First", reporter=self.r)
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self.a.save()
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# Create an Article via the Reporter object.
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self.a2 = self.r.article_set.create(headline="Second")
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# Create an Article with no Reporter by passing "reporter=None".
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self.a3 = Article(headline="Third", reporter=None)
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self.a3.save()
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# Create another article and reporter
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self.r2 = Reporter(name='Paul Jones')
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self.r2.save()
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self.a4 = self.r2.article_set.create(headline='Fourth')
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def test_get_related(self):
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self.assertEqual(self.a.reporter.id, self.r.id)
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# Article objects have access to their related Reporter objects.
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r = self.a.reporter
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self.assertEqual(r.id, self.r.id)
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def test_created_via_related_set(self):
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self.assertEqual(self.a2.reporter.id, self.r.id)
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def test_related_set(self):
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# Reporter objects have access to their related Article objects.
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.assertQuerysetEqual(self.r.article_set.filter(headline__startswith='Fir'),
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['<Article: First>'])
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self.assertEqual(self.r.article_set.count(), 2)
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def test_created_without_related(self):
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self.assertEqual(self.a3.reporter, None)
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# Need to reget a3 to refresh the cache
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a3 = Article.objects.get(pk=self.a3.pk)
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self.assertRaises(AttributeError, getattr, a3.reporter, 'id')
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# Accessing an article's 'reporter' attribute returns None
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# if the reporter is set to None.
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self.assertEqual(a3.reporter, None)
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# To retrieve the articles with no reporters set, use "reporter__isnull=True".
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: Third>'])
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# We can achieve the same thing by filtering for the case where the
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# reporter is None.
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self.assertQuerysetEqual(Article.objects.filter(reporter=None),
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['<Article: Third>'])
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# Set the reporter for the Third article
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.r.article_set.add(a3)
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>', '<Article: Third>'])
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# Remove an article from the set, and check that it was removed.
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self.r.article_set.remove(a3)
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: Third>'])
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def test_remove_from_wrong_set(self):
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self.assertQuerysetEqual(self.r2.article_set.all(), ['<Article: Fourth>'])
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# Try to remove a4 from a set it does not belong to
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self.assertRaises(Reporter.DoesNotExist, self.r.article_set.remove, self.a4)
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self.assertQuerysetEqual(self.r2.article_set.all(), ['<Article: Fourth>'])
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def test_set(self):
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# Use manager.set() to allocate ForeignKey. Null is legal, so existing
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# members of the set that are not in the assignment set are set to null.
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self.r2.article_set.set([self.a2, self.a3])
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self.assertQuerysetEqual(self.r2.article_set.all(),
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['<Article: Second>', '<Article: Third>'])
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# Use manager.set(clear=True)
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self.r2.article_set.set([self.a3, self.a4], clear=True)
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self.assertQuerysetEqual(self.r2.article_set.all(),
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['<Article: Fourth>', '<Article: Third>'])
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# Clear the rest of the set
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self.r2.article_set.set([])
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self.assertQuerysetEqual(self.r2.article_set.all(), [])
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: Fourth>', '<Article: Second>', '<Article: Third>'])
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def test_assign_clear_related_set(self):
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# Use descriptor assignment to allocate ForeignKey. Null is legal, so
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# existing members of the set that are not in the assignment set are
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# set to null.
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self.r2.article_set = [self.a2, self.a3]
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self.assertQuerysetEqual(self.r2.article_set.all(),
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['<Article: Second>', '<Article: Third>'])
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# Clear the rest of the set
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self.r.article_set.clear()
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self.assertQuerysetEqual(self.r.article_set.all(), [])
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: First>', '<Article: Fourth>'])
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def test_assign_with_queryset(self):
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# Ensure that querysets used in reverse FK assignments are pre-evaluated
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# so their value isn't affected by the clearing operation in
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# ReverseManyToOneDescriptor.__set__. Refs #19816.
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self.r2.article_set = [self.a2, self.a3]
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qs = self.r2.article_set.filter(headline="Second")
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self.r2.article_set = qs
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self.assertEqual(1, self.r2.article_set.count())
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self.assertEqual(1, qs.count())
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def test_add_efficiency(self):
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r = Reporter.objects.create()
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articles = []
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for _ in range(3):
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articles.append(Article.objects.create())
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with self.assertNumQueries(1):
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r.article_set.add(*articles)
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self.assertEqual(r.article_set.count(), 3)
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def test_clear_efficiency(self):
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r = Reporter.objects.create()
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for _ in range(3):
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r.article_set.create()
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with self.assertNumQueries(1):
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r.article_set.clear()
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self.assertEqual(r.article_set.count(), 0)
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def test_related_null_to_field(self):
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c1 = Car.objects.create()
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d1 = Driver.objects.create()
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self.assertIs(d1.car, None)
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with self.assertNumQueries(0):
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self.assertEqual(list(c1.drivers.all()), [])
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