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5643a3b51b
This prevents silent data loss. Thanks Aymeric Augustin for the initial patch and Loic Bistuer for the review.
133 lines
5.5 KiB
Python
133 lines
5.5 KiB
Python
from __future__ import unicode_literals
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from django.db import models
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from django.test import TestCase
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from .models import (
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First, Third, Parent, Child, Category, Record, Relation, Car, Driver)
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class ManyToOneRegressionTests(TestCase):
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def test_object_creation(self):
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Third.objects.create(id='3', name='An example')
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parent = Parent(name='fred')
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parent.save()
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Child.objects.create(name='bam-bam', parent=parent)
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def test_fk_assignment_and_related_object_cache(self):
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# Tests of ForeignKey assignment and the related-object cache (see #6886).
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p = Parent.objects.create(name="Parent")
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c = Child.objects.create(name="Child", parent=p)
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# Look up the object again so that we get a "fresh" object.
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c = Child.objects.get(name="Child")
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p = c.parent
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# Accessing the related object again returns the exactly same object.
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self.assertTrue(c.parent is p)
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# But if we kill the cache, we get a new object.
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del c._parent_cache
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self.assertFalse(c.parent is p)
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# Assigning a new object results in that object getting cached immediately.
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p2 = Parent.objects.create(name="Parent 2")
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c.parent = p2
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self.assertTrue(c.parent is p2)
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# Assigning None succeeds if field is null=True.
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p.bestchild = None
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self.assertTrue(p.bestchild is None)
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# bestchild should still be None after saving.
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p.save()
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self.assertTrue(p.bestchild is None)
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# bestchild should still be None after fetching the object again.
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p = Parent.objects.get(name="Parent")
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self.assertTrue(p.bestchild is None)
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# Assigning None fails: Child.parent is null=False.
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self.assertRaises(ValueError, setattr, c, "parent", None)
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# You also can't assign an object of the wrong type here
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self.assertRaises(ValueError, setattr, c, "parent", First(id=1, second=1))
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# Nor can you explicitly assign None to Child.parent during object
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# creation (regression for #9649).
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self.assertRaises(ValueError, Child, name='xyzzy', parent=None)
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self.assertRaises(ValueError, Child.objects.create, name='xyzzy', parent=None)
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# Creation using keyword argument should cache the related object.
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p = Parent.objects.get(name="Parent")
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c = Child(parent=p)
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self.assertTrue(c.parent is p)
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# Creation using keyword argument and unsaved related instance (#8070).
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p = Parent()
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with self.assertRaisesMessage(ValueError,
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'Cannot assign "%r": "%s" instance isn\'t saved in the database.'
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% (p, Child.parent.field.rel.to._meta.object_name)):
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Child(parent=p)
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# Creation using attname keyword argument and an id will cause the
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# related object to be fetched.
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p = Parent.objects.get(name="Parent")
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c = Child(parent_id=p.id)
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self.assertFalse(c.parent is p)
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self.assertEqual(c.parent, p)
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def test_multiple_foreignkeys(self):
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# Test of multiple ForeignKeys to the same model (bug #7125).
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c1 = Category.objects.create(name='First')
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c2 = Category.objects.create(name='Second')
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c3 = Category.objects.create(name='Third')
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r1 = Record.objects.create(category=c1)
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r2 = Record.objects.create(category=c1)
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r3 = Record.objects.create(category=c2)
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r4 = Record.objects.create(category=c2)
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r5 = Record.objects.create(category=c3)
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Relation.objects.create(left=r1, right=r2)
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Relation.objects.create(left=r3, right=r4)
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Relation.objects.create(left=r1, right=r3)
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Relation.objects.create(left=r5, right=r2)
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Relation.objects.create(left=r3, right=r2)
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q1 = Relation.objects.filter(left__category__name__in=['First'], right__category__name__in=['Second'])
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self.assertQuerysetEqual(q1, ["<Relation: First - Second>"])
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q2 = Category.objects.filter(record__left_set__right__category__name='Second').order_by('name')
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self.assertQuerysetEqual(q2, ["<Category: First>", "<Category: Second>"])
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p = Parent.objects.create(name="Parent")
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c = Child.objects.create(name="Child", parent=p)
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self.assertRaises(ValueError, Child.objects.create, name="Grandchild", parent=c)
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def test_fk_instantiation_outside_model(self):
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# Regression for #12190 -- Should be able to instantiate a FK outside
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# of a model, and interrogate its related field.
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cat = models.ForeignKey(Category)
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self.assertEqual('id', cat.rel.get_related_field().name)
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def test_relation_unsaved(self):
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# Test that the <field>_set manager does not join on Null value fields (#17541)
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Third.objects.create(name='Third 1')
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Third.objects.create(name='Third 2')
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th = Third(name="testing")
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# The object isn't saved an thus the relation field is null - we won't even
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# execute a query in this case.
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with self.assertNumQueries(0):
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self.assertEqual(th.child_set.count(), 0)
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th.save()
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# Now the model is saved, so we will need to execute an query.
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with self.assertNumQueries(1):
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self.assertEqual(th.child_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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