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268 lines
11 KiB
Python
268 lines
11 KiB
Python
from __future__ import unicode_literals
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from django.db.models.query_utils import DeferredAttribute, InvalidQuery
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from django.test import TestCase
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from .models import (
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BigChild, Child, ChildProxy, Primary, RefreshPrimaryProxy, Secondary,
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)
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class AssertionMixin(object):
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def assert_delayed(self, obj, num):
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"""
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Instances with deferred fields look the same as normal instances when
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we examine attribute values. Therefore, this method returns the number
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of deferred fields on returned instances.
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"""
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count = 0
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for field in obj._meta.fields:
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if isinstance(obj.__class__.__dict__.get(field.attname), DeferredAttribute):
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count += 1
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self.assertEqual(count, num)
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class DeferTests(AssertionMixin, TestCase):
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@classmethod
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def setUpTestData(cls):
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cls.s1 = Secondary.objects.create(first="x1", second="y1")
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cls.p1 = Primary.objects.create(name="p1", value="xx", related=cls.s1)
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def test_defer(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.defer("name")[0], 1)
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self.assert_delayed(qs.defer("name").get(pk=self.p1.pk), 1)
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self.assert_delayed(qs.defer("related__first")[0], 0)
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self.assert_delayed(qs.defer("name").defer("value")[0], 2)
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def test_only(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.only("name")[0], 2)
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self.assert_delayed(qs.only("name").get(pk=self.p1.pk), 2)
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self.assert_delayed(qs.only("name").only("value")[0], 2)
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self.assert_delayed(qs.only("related__first")[0], 2)
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# Using 'pk' with only() should result in 3 deferred fields, namely all
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# of them except the model's primary key see #15494
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self.assert_delayed(qs.only("pk")[0], 3)
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# You can use 'pk' with reverse foreign key lookups.
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self.assert_delayed(self.s1.primary_set.all().only('pk')[0], 3)
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def test_defer_only_chaining(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.only("name", "value").defer("name")[0], 2)
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self.assert_delayed(qs.defer("name").only("value", "name")[0], 2)
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self.assert_delayed(qs.defer("name").only("value")[0], 2)
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self.assert_delayed(qs.only("name").defer("value")[0], 2)
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def test_defer_on_an_already_deferred_field(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.defer("name")[0], 1)
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self.assert_delayed(qs.defer("name").defer("name")[0], 1)
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def test_defer_none_to_clear_deferred_set(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.defer("name", "value")[0], 2)
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self.assert_delayed(qs.defer(None)[0], 0)
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self.assert_delayed(qs.only("name").defer(None)[0], 0)
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def test_only_none_raises_error(self):
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msg = 'Cannot pass None as an argument to only().'
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with self.assertRaisesMessage(TypeError, msg):
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Primary.objects.only(None)
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def test_defer_extra(self):
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qs = Primary.objects.all()
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self.assert_delayed(qs.defer("name").extra(select={"a": 1})[0], 1)
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self.assert_delayed(qs.extra(select={"a": 1}).defer("name")[0], 1)
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def test_defer_values_does_not_defer(self):
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# User values() won't defer anything (you get the full list of
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# dictionaries back), but it still works.
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self.assertEqual(Primary.objects.defer("name").values()[0], {
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"id": self.p1.id,
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"name": "p1",
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"value": "xx",
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"related_id": self.s1.id,
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})
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def test_only_values_does_not_defer(self):
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self.assertEqual(Primary.objects.only("name").values()[0], {
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"id": self.p1.id,
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"name": "p1",
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"value": "xx",
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"related_id": self.s1.id,
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})
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def test_get(self):
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# Using defer() and only() with get() is also valid.
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qs = Primary.objects.all()
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self.assert_delayed(qs.defer("name").get(pk=self.p1.pk), 1)
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self.assert_delayed(qs.only("name").get(pk=self.p1.pk), 2)
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def test_defer_with_select_related(self):
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obj = Primary.objects.select_related().defer("related__first", "related__second")[0]
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self.assert_delayed(obj.related, 2)
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self.assert_delayed(obj, 0)
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def test_only_with_select_related(self):
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obj = Primary.objects.select_related().only("related__first")[0]
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self.assert_delayed(obj, 2)
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self.assert_delayed(obj.related, 1)
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self.assertEqual(obj.related_id, self.s1.pk)
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self.assertEqual(obj.name, "p1")
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def test_defer_select_related_raises_invalid_query(self):
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# When we defer a field and also select_related it, the query is
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# invalid and raises an exception.
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with self.assertRaises(InvalidQuery):
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Primary.objects.defer("related").select_related("related")[0]
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def test_only_select_related_raises_invalid_query(self):
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with self.assertRaises(InvalidQuery):
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Primary.objects.only("name").select_related("related")[0]
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def test_defer_foreign_keys_are_deferred_and_not_traversed(self):
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# With a depth-based select_related, all deferred ForeignKeys are
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# deferred instead of traversed.
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with self.assertNumQueries(3):
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obj = Primary.objects.defer("related").select_related()[0]
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self.assert_delayed(obj, 1)
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self.assertEqual(obj.related.id, self.s1.pk)
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def test_saving_object_with_deferred_field(self):
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# Saving models with deferred fields is possible (but inefficient,
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# since every field has to be retrieved first).
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Primary.objects.create(name="p2", value="xy", related=self.s1)
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obj = Primary.objects.defer("value").get(name="p2")
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obj.name = "a new name"
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obj.save()
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self.assertQuerysetEqual(
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Primary.objects.all(), [
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"p1", "a new name",
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],
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lambda p: p.name,
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ordered=False,
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)
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def test_defer_baseclass_when_subclass_has_no_added_fields(self):
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# Regression for #10572 - A subclass with no extra fields can defer
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# fields from the base class
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Child.objects.create(name="c1", value="foo", related=self.s1)
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# You can defer a field on a baseclass when the subclass has no fields
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obj = Child.objects.defer("value").get(name="c1")
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self.assert_delayed(obj, 1)
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self.assertEqual(obj.name, "c1")
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self.assertEqual(obj.value, "foo")
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def test_only_baseclass_when_subclass_has_no_added_fields(self):
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# You can retrieve a single column on a base class with no fields
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Child.objects.create(name="c1", value="foo", related=self.s1)
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obj = Child.objects.only("name").get(name="c1")
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# on an inherited model, its PK is also fetched, hence '3' deferred fields.
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self.assert_delayed(obj, 3)
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self.assertEqual(obj.name, "c1")
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self.assertEqual(obj.value, "foo")
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class BigChildDeferTests(AssertionMixin, TestCase):
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@classmethod
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def setUpTestData(cls):
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cls.s1 = Secondary.objects.create(first="x1", second="y1")
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BigChild.objects.create(name="b1", value="foo", related=cls.s1, other="bar")
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def test_defer_baseclass_when_subclass_has_added_field(self):
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# You can defer a field on a baseclass
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obj = BigChild.objects.defer("value").get(name="b1")
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self.assert_delayed(obj, 1)
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self.assertEqual(obj.name, "b1")
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self.assertEqual(obj.value, "foo")
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self.assertEqual(obj.other, "bar")
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def test_defer_subclass(self):
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# You can defer a field on a subclass
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obj = BigChild.objects.defer("other").get(name="b1")
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self.assert_delayed(obj, 1)
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self.assertEqual(obj.name, "b1")
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self.assertEqual(obj.value, "foo")
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self.assertEqual(obj.other, "bar")
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def test_only_baseclass_when_subclass_has_added_field(self):
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# You can retrieve a single field on a baseclass
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obj = BigChild.objects.only("name").get(name="b1")
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# when inherited model, its PK is also fetched, hence '4' deferred fields.
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self.assert_delayed(obj, 4)
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self.assertEqual(obj.name, "b1")
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self.assertEqual(obj.value, "foo")
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self.assertEqual(obj.other, "bar")
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def test_only_sublcass(self):
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# You can retrieve a single field on a subclass
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obj = BigChild.objects.only("other").get(name="b1")
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self.assert_delayed(obj, 4)
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self.assertEqual(obj.name, "b1")
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self.assertEqual(obj.value, "foo")
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self.assertEqual(obj.other, "bar")
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class TestDefer2(AssertionMixin, TestCase):
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def test_defer_proxy(self):
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"""
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Ensure select_related together with only on a proxy model behaves
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as expected. See #17876.
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"""
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related = Secondary.objects.create(first='x1', second='x2')
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ChildProxy.objects.create(name='p1', value='xx', related=related)
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children = ChildProxy.objects.all().select_related().only('id', 'name')
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self.assertEqual(len(children), 1)
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child = children[0]
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self.assert_delayed(child, 2)
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self.assertEqual(child.name, 'p1')
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self.assertEqual(child.value, 'xx')
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def test_defer_inheritance_pk_chaining(self):
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"""
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When an inherited model is fetched from the DB, its PK is also fetched.
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When getting the PK of the parent model it is useful to use the already
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fetched parent model PK if it happens to be available. Tests that this
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is done.
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"""
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s1 = Secondary.objects.create(first="x1", second="y1")
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bc = BigChild.objects.create(name="b1", value="foo", related=s1,
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other="bar")
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bc_deferred = BigChild.objects.only('name').get(pk=bc.pk)
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with self.assertNumQueries(0):
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bc_deferred.id
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self.assertEqual(bc_deferred.pk, bc_deferred.id)
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def test_eq(self):
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s1 = Secondary.objects.create(first="x1", second="y1")
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s1_defer = Secondary.objects.only('pk').get(pk=s1.pk)
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self.assertEqual(s1, s1_defer)
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self.assertEqual(s1_defer, s1)
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def test_refresh_not_loading_deferred_fields(self):
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s = Secondary.objects.create()
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rf = Primary.objects.create(name='foo', value='bar', related=s)
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rf2 = Primary.objects.only('related', 'value').get()
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rf.name = 'new foo'
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rf.value = 'new bar'
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rf.save()
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with self.assertNumQueries(1):
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rf2.refresh_from_db()
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self.assertEqual(rf2.value, 'new bar')
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with self.assertNumQueries(1):
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self.assertEqual(rf2.name, 'new foo')
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def test_custom_refresh_on_deferred_loading(self):
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s = Secondary.objects.create()
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rf = RefreshPrimaryProxy.objects.create(name='foo', value='bar', related=s)
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rf2 = RefreshPrimaryProxy.objects.only('related').get()
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rf.name = 'new foo'
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rf.value = 'new bar'
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rf.save()
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with self.assertNumQueries(1):
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# Customized refresh_from_db() reloads all deferred fields on
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# access of any of them.
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self.assertEqual(rf2.name, 'new foo')
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self.assertEqual(rf2.value, 'new bar')
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