182 lines
7.3 KiB
Python
182 lines
7.3 KiB
Python
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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@classmethod
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def setUpTestData(cls):
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# Create a Reporter.
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cls.r = Reporter(name="John Smith")
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cls.r.save()
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# Create an Article.
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cls.a = Article(headline="First", reporter=cls.r)
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cls.a.save()
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# Create an Article via the Reporter object.
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cls.a2 = cls.r.article_set.create(headline="Second")
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# Create an Article with no Reporter by passing "reporter=None".
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cls.a3 = Article(headline="Third", reporter=None)
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cls.a3.save()
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# Create another article and reporter
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cls.r2 = Reporter(name="Paul Jones")
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cls.r2.save()
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cls.a4 = cls.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.assertSequenceEqual(self.r.article_set.all(), [self.a, self.a2])
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self.assertSequenceEqual(
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self.r.article_set.filter(headline__startswith="Fir"), [self.a]
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)
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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.assertIsNone(self.a3.reporter)
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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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with self.assertRaises(AttributeError):
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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.assertIsNone(a3.reporter)
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# To retrieve the articles with no reporters set, use "reporter__isnull=True".
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self.assertSequenceEqual(
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Article.objects.filter(reporter__isnull=True), [self.a3]
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)
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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.assertSequenceEqual(Article.objects.filter(reporter=None), [self.a3])
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# Set the reporter for the Third article
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self.assertSequenceEqual(self.r.article_set.all(), [self.a, self.a2])
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self.r.article_set.add(a3)
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self.assertSequenceEqual(
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self.r.article_set.all(),
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[self.a, self.a2, self.a3],
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)
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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.assertSequenceEqual(self.r.article_set.all(), [self.a, self.a2])
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self.assertSequenceEqual(
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Article.objects.filter(reporter__isnull=True), [self.a3]
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)
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def test_remove_from_wrong_set(self):
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self.assertSequenceEqual(self.r2.article_set.all(), [self.a4])
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# Try to remove a4 from a set it does not belong to
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with self.assertRaises(Reporter.DoesNotExist):
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self.r.article_set.remove(self.a4)
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self.assertSequenceEqual(self.r2.article_set.all(), [self.a4])
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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.assertSequenceEqual(self.r2.article_set.all(), [self.a2, self.a3])
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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.assertSequenceEqual(self.r2.article_set.all(), [self.a4, self.a3])
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# Clear the rest of the set
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self.r2.article_set.set([])
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self.assertSequenceEqual(self.r2.article_set.all(), [])
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self.assertSequenceEqual(
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Article.objects.filter(reporter__isnull=True),
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[self.a4, self.a2, self.a3],
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)
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def test_set_clear_non_bulk(self):
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# 2 queries for clear(), 1 for add(), and 1 to select objects.
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with self.assertNumQueries(4):
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self.r.article_set.set([self.a], bulk=False, clear=True)
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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.set([self.a2, self.a3])
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self.assertSequenceEqual(self.r2.article_set.all(), [self.a2, self.a3])
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# Clear the rest of the set
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self.r.article_set.clear()
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self.assertSequenceEqual(self.r.article_set.all(), [])
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self.assertSequenceEqual(
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Article.objects.filter(reporter__isnull=True),
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[self.a, self.a4],
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)
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def test_assign_with_queryset(self):
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# 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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# RelatedManager.set() (#19816).
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self.r2.article_set.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.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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def test_unsaved(self):
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msg = (
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"'Car' instance needs to have a primary key value before this relationship "
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"can be used."
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)
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with self.assertRaisesMessage(ValueError, msg):
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Car(make="Ford").drivers.all()
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def test_related_null_to_field_related_managers(self):
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car = Car.objects.create(make=None)
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driver = Driver.objects.create()
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msg = (
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f'"{car!r}" needs to have a value for field "make" before this '
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f"relationship can be used."
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)
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.add(driver)
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.create()
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.get_or_create()
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.update_or_create()
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.remove(driver)
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.clear()
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with self.assertRaisesMessage(ValueError, msg):
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car.drivers.set([driver])
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with self.assertNumQueries(0):
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self.assertEqual(car.drivers.count(), 0)
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