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115 lines
5.1 KiB
Python
115 lines
5.1 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_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 set that are not in the assignment set are set 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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# ForeignRelatedObjectsDescriptor.__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_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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