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django/tests/many_to_one/tests.py
Allen Jonathan David 1058fc7023 Fixed #33191 -- Avoided clearing cached reference when saving child after parent.
Thanks Barry Johnson for the report.
2022-05-31 10:19:54 +02:00

877 lines
34 KiB
Python

import datetime
from copy import deepcopy
from django.core.exceptions import FieldError, MultipleObjectsReturned
from django.db import IntegrityError, models, transaction
from django.test import TestCase
from django.utils.translation import gettext_lazy
from .models import (
Article,
Category,
Child,
ChildNullableParent,
ChildStringPrimaryKeyParent,
City,
Country,
District,
First,
Parent,
ParentStringPrimaryKey,
Record,
Relation,
Reporter,
School,
Student,
Third,
ToFieldChild,
)
class ManyToOneTests(TestCase):
@classmethod
def setUpTestData(cls):
# Create a few Reporters.
cls.r = Reporter(first_name="John", last_name="Smith", email="john@example.com")
cls.r.save()
cls.r2 = Reporter(
first_name="Paul", last_name="Jones", email="paul@example.com"
)
cls.r2.save()
# Create an Article.
cls.a = Article(
headline="This is a test",
pub_date=datetime.date(2005, 7, 27),
reporter=cls.r,
)
cls.a.save()
def test_get(self):
# Article objects have access to their related Reporter objects.
r = self.a.reporter
self.assertEqual(r.id, self.r.id)
self.assertEqual((r.first_name, self.r.last_name), ("John", "Smith"))
def test_create(self):
# You can also instantiate an Article by passing the Reporter's ID
# instead of a Reporter object.
a3 = Article(
headline="Third article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=self.r.id,
)
a3.save()
self.assertEqual(a3.reporter.id, self.r.id)
# Similarly, the reporter ID can be a string.
a4 = Article(
headline="Fourth article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=str(self.r.id),
)
a4.save()
self.assertEqual(repr(a4.reporter), "<Reporter: John Smith>")
def test_add(self):
# Create an Article via the Reporter object.
new_article = self.r.article_set.create(
headline="John's second story", pub_date=datetime.date(2005, 7, 29)
)
self.assertEqual(repr(new_article), "<Article: John's second story>")
self.assertEqual(new_article.reporter.id, self.r.id)
# Create a new article, and add it to the article set.
new_article2 = Article(
headline="Paul's story", pub_date=datetime.date(2006, 1, 17)
)
msg = (
"<Article: Paul's story> instance isn't saved. Use bulk=False or save the "
"object first."
)
with self.assertRaisesMessage(ValueError, msg):
self.r.article_set.add(new_article2)
self.r.article_set.add(new_article2, bulk=False)
self.assertEqual(new_article2.reporter.id, self.r.id)
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, new_article2, self.a],
)
# Add the same article to a different article set - check that it moves.
self.r2.article_set.add(new_article2)
self.assertEqual(new_article2.reporter.id, self.r2.id)
self.assertSequenceEqual(self.r2.article_set.all(), [new_article2])
# Adding an object of the wrong type raises TypeError.
with transaction.atomic():
with self.assertRaisesMessage(
TypeError, "'Article' instance expected, got <Reporter:"
):
self.r.article_set.add(self.r2)
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, self.a],
)
def test_set(self):
new_article = self.r.article_set.create(
headline="John's second story", pub_date=datetime.date(2005, 7, 29)
)
new_article2 = self.r2.article_set.create(
headline="Paul's story", pub_date=datetime.date(2006, 1, 17)
)
# Assign the article to the reporter.
new_article2.reporter = self.r
new_article2.save()
self.assertEqual(repr(new_article2.reporter), "<Reporter: John Smith>")
self.assertEqual(new_article2.reporter.id, self.r.id)
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, new_article2, self.a],
)
self.assertSequenceEqual(self.r2.article_set.all(), [])
# Set the article back again.
self.r2.article_set.set([new_article, new_article2])
self.assertSequenceEqual(self.r.article_set.all(), [self.a])
self.assertSequenceEqual(
self.r2.article_set.all(),
[new_article, new_article2],
)
# Funny case - because the ForeignKey cannot be null,
# existing members of the set must remain.
self.r.article_set.set([new_article])
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, self.a],
)
self.assertSequenceEqual(self.r2.article_set.all(), [new_article2])
def test_reverse_assignment_deprecation(self):
msg = (
"Direct assignment to the reverse side of a related set is "
"prohibited. Use article_set.set() instead."
)
with self.assertRaisesMessage(TypeError, msg):
self.r2.article_set = []
def test_assign(self):
new_article = self.r.article_set.create(
headline="John's second story", pub_date=datetime.date(2005, 7, 29)
)
new_article2 = self.r2.article_set.create(
headline="Paul's story", pub_date=datetime.date(2006, 1, 17)
)
# Assign the article to the reporter directly using the descriptor.
new_article2.reporter = self.r
new_article2.save()
self.assertEqual(repr(new_article2.reporter), "<Reporter: John Smith>")
self.assertEqual(new_article2.reporter.id, self.r.id)
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, new_article2, self.a],
)
self.assertSequenceEqual(self.r2.article_set.all(), [])
# Set the article back again using set() method.
self.r2.article_set.set([new_article, new_article2])
self.assertSequenceEqual(self.r.article_set.all(), [self.a])
self.assertSequenceEqual(
self.r2.article_set.all(),
[new_article, new_article2],
)
# Because the ForeignKey cannot be null, existing members of the set
# must remain.
self.r.article_set.set([new_article])
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article, self.a],
)
self.assertSequenceEqual(self.r2.article_set.all(), [new_article2])
# Reporter cannot be null - there should not be a clear or remove method
self.assertFalse(hasattr(self.r2.article_set, "remove"))
self.assertFalse(hasattr(self.r2.article_set, "clear"))
def test_assign_fk_id_value(self):
parent = Parent.objects.create(name="jeff")
child1 = Child.objects.create(name="frank", parent=parent)
child2 = Child.objects.create(name="randy", parent=parent)
parent.bestchild = child1
parent.save()
parent.bestchild_id = child2.pk
parent.save()
self.assertEqual(parent.bestchild_id, child2.pk)
self.assertFalse(Parent.bestchild.is_cached(parent))
self.assertEqual(parent.bestchild, child2)
self.assertTrue(Parent.bestchild.is_cached(parent))
# Reassigning the same value doesn't clear cached instance.
parent.bestchild_id = child2.pk
self.assertTrue(Parent.bestchild.is_cached(parent))
def test_assign_fk_id_none(self):
parent = Parent.objects.create(name="jeff")
child = Child.objects.create(name="frank", parent=parent)
parent.bestchild = child
parent.save()
parent.bestchild_id = None
parent.save()
self.assertIsNone(parent.bestchild_id)
self.assertFalse(Parent.bestchild.is_cached(parent))
self.assertIsNone(parent.bestchild)
self.assertTrue(Parent.bestchild.is_cached(parent))
def test_selects(self):
new_article1 = self.r.article_set.create(
headline="John's second story",
pub_date=datetime.date(2005, 7, 29),
)
new_article2 = self.r2.article_set.create(
headline="Paul's story",
pub_date=datetime.date(2006, 1, 17),
)
# Reporter objects have access to their related Article objects.
self.assertSequenceEqual(
self.r.article_set.all(),
[new_article1, self.a],
)
self.assertSequenceEqual(
self.r.article_set.filter(headline__startswith="This"), [self.a]
)
self.assertEqual(self.r.article_set.count(), 2)
self.assertEqual(self.r2.article_set.count(), 1)
# Get articles by id
self.assertSequenceEqual(Article.objects.filter(id__exact=self.a.id), [self.a])
self.assertSequenceEqual(Article.objects.filter(pk=self.a.id), [self.a])
# Query on an article property
self.assertSequenceEqual(
Article.objects.filter(headline__startswith="This"), [self.a]
)
# The API automatically follows relationships as far as you need.
# Use double underscores to separate relationships.
# This works as many levels deep as you want. There's no limit.
# Find all Articles for any Reporter whose first name is "John".
self.assertSequenceEqual(
Article.objects.filter(reporter__first_name__exact="John"),
[new_article1, self.a],
)
# Implied __exact also works
self.assertSequenceEqual(
Article.objects.filter(reporter__first_name="John"),
[new_article1, self.a],
)
# Query twice over the related field.
self.assertSequenceEqual(
Article.objects.filter(
reporter__first_name__exact="John", reporter__last_name__exact="Smith"
),
[new_article1, self.a],
)
# The underlying query only makes one join when a related table is
# referenced twice.
queryset = Article.objects.filter(
reporter__first_name__exact="John", reporter__last_name__exact="Smith"
)
self.assertNumQueries(1, list, queryset)
self.assertEqual(
queryset.query.get_compiler(queryset.db).as_sql()[0].count("INNER JOIN"), 1
)
# The automatically joined table has a predictable name.
self.assertSequenceEqual(
Article.objects.filter(reporter__first_name__exact="John").extra(
where=["many_to_one_reporter.last_name='Smith'"]
),
[new_article1, self.a],
)
# ... and should work fine with the string that comes out of
# forms.Form.cleaned_data.
self.assertQuerysetEqual(
(
Article.objects.filter(reporter__first_name__exact="John").extra(
where=["many_to_one_reporter.last_name='%s'" % "Smith"]
)
),
[new_article1, self.a],
)
# Find all Articles for a Reporter.
# Use direct ID check, pk check, and object comparison
self.assertSequenceEqual(
Article.objects.filter(reporter__id__exact=self.r.id),
[new_article1, self.a],
)
self.assertSequenceEqual(
Article.objects.filter(reporter__pk=self.r.id),
[new_article1, self.a],
)
self.assertSequenceEqual(
Article.objects.filter(reporter=self.r.id),
[new_article1, self.a],
)
self.assertSequenceEqual(
Article.objects.filter(reporter=self.r),
[new_article1, self.a],
)
self.assertSequenceEqual(
Article.objects.filter(reporter__in=[self.r.id, self.r2.id]).distinct(),
[new_article1, new_article2, self.a],
)
self.assertSequenceEqual(
Article.objects.filter(reporter__in=[self.r, self.r2]).distinct(),
[new_article1, new_article2, self.a],
)
# You can also use a queryset instead of a literal list of instances.
# The queryset must be reduced to a list of values using values(),
# then converted into a query
self.assertSequenceEqual(
Article.objects.filter(
reporter__in=Reporter.objects.filter(first_name="John")
.values("pk")
.query
).distinct(),
[new_article1, self.a],
)
def test_reverse_selects(self):
a3 = Article.objects.create(
headline="Third article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=self.r.id,
)
Article.objects.create(
headline="Fourth article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=self.r.id,
)
john_smith = [self.r]
# Reporters can be queried
self.assertSequenceEqual(
Reporter.objects.filter(id__exact=self.r.id), john_smith
)
self.assertSequenceEqual(Reporter.objects.filter(pk=self.r.id), john_smith)
self.assertSequenceEqual(
Reporter.objects.filter(first_name__startswith="John"), john_smith
)
# Reporters can query in opposite direction of ForeignKey definition
self.assertSequenceEqual(
Reporter.objects.filter(article__id__exact=self.a.id), john_smith
)
self.assertSequenceEqual(
Reporter.objects.filter(article__pk=self.a.id), john_smith
)
self.assertSequenceEqual(Reporter.objects.filter(article=self.a.id), john_smith)
self.assertSequenceEqual(Reporter.objects.filter(article=self.a), john_smith)
self.assertSequenceEqual(
Reporter.objects.filter(article__in=[self.a.id, a3.id]).distinct(),
john_smith,
)
self.assertSequenceEqual(
Reporter.objects.filter(article__in=[self.a.id, a3]).distinct(), john_smith
)
self.assertSequenceEqual(
Reporter.objects.filter(article__in=[self.a, a3]).distinct(), john_smith
)
self.assertCountEqual(
Reporter.objects.filter(article__headline__startswith="T"),
[self.r, self.r],
)
self.assertSequenceEqual(
Reporter.objects.filter(article__headline__startswith="T").distinct(),
john_smith,
)
# Counting in the opposite direction works in conjunction with distinct()
self.assertEqual(
Reporter.objects.filter(article__headline__startswith="T").count(), 2
)
self.assertEqual(
Reporter.objects.filter(article__headline__startswith="T")
.distinct()
.count(),
1,
)
# Queries can go round in circles.
self.assertCountEqual(
Reporter.objects.filter(article__reporter__first_name__startswith="John"),
[self.r, self.r, self.r],
)
self.assertSequenceEqual(
Reporter.objects.filter(
article__reporter__first_name__startswith="John"
).distinct(),
john_smith,
)
self.assertSequenceEqual(
Reporter.objects.filter(article__reporter__exact=self.r).distinct(),
john_smith,
)
# Implied __exact also works.
self.assertSequenceEqual(
Reporter.objects.filter(article__reporter=self.r).distinct(), john_smith
)
# It's possible to use values() calls across many-to-one relations.
# (Note, too, that we clear the ordering here so as not to drag the
# 'headline' field into the columns being used to determine uniqueness)
d = {"reporter__first_name": "John", "reporter__last_name": "Smith"}
qs = (
Article.objects.filter(
reporter=self.r,
)
.distinct()
.order_by()
.values("reporter__first_name", "reporter__last_name")
)
self.assertEqual([d], list(qs))
def test_select_related(self):
# Article.objects.select_related().dates() works properly when there
# are multiple Articles with the same date but different foreign-key
# objects (Reporters).
r1 = Reporter.objects.create(
first_name="Mike", last_name="Royko", email="royko@suntimes.com"
)
r2 = Reporter.objects.create(
first_name="John", last_name="Kass", email="jkass@tribune.com"
)
Article.objects.create(
headline="First", pub_date=datetime.date(1980, 4, 23), reporter=r1
)
Article.objects.create(
headline="Second", pub_date=datetime.date(1980, 4, 23), reporter=r2
)
self.assertEqual(
list(Article.objects.select_related().dates("pub_date", "day")),
[datetime.date(1980, 4, 23), datetime.date(2005, 7, 27)],
)
self.assertEqual(
list(Article.objects.select_related().dates("pub_date", "month")),
[datetime.date(1980, 4, 1), datetime.date(2005, 7, 1)],
)
self.assertEqual(
list(Article.objects.select_related().dates("pub_date", "year")),
[datetime.date(1980, 1, 1), datetime.date(2005, 1, 1)],
)
def test_delete(self):
new_article1 = self.r.article_set.create(
headline="John's second story",
pub_date=datetime.date(2005, 7, 29),
)
new_article2 = self.r2.article_set.create(
headline="Paul's story",
pub_date=datetime.date(2006, 1, 17),
)
new_article3 = Article.objects.create(
headline="Third article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=self.r.id,
)
new_article4 = Article.objects.create(
headline="Fourth article",
pub_date=datetime.date(2005, 7, 27),
reporter_id=str(self.r.id),
)
# If you delete a reporter, their articles will be deleted.
self.assertSequenceEqual(
Article.objects.all(),
[new_article4, new_article1, new_article2, new_article3, self.a],
)
self.assertSequenceEqual(
Reporter.objects.order_by("first_name"),
[self.r, self.r2],
)
self.r2.delete()
self.assertSequenceEqual(
Article.objects.all(),
[new_article4, new_article1, new_article3, self.a],
)
self.assertSequenceEqual(Reporter.objects.order_by("first_name"), [self.r])
# You can delete using a JOIN in the query.
Reporter.objects.filter(article__headline__startswith="This").delete()
self.assertSequenceEqual(Reporter.objects.all(), [])
self.assertSequenceEqual(Article.objects.all(), [])
def test_explicit_fk(self):
# Create a new Article with get_or_create using an explicit value
# for a ForeignKey.
a2, created = Article.objects.get_or_create(
headline="John's second test",
pub_date=datetime.date(2011, 5, 7),
reporter_id=self.r.id,
)
self.assertTrue(created)
self.assertEqual(a2.reporter.id, self.r.id)
# You can specify filters containing the explicit FK value.
self.assertSequenceEqual(
Article.objects.filter(reporter_id__exact=self.r.id),
[a2, self.a],
)
# Create an Article by Paul for the same date.
a3 = Article.objects.create(
headline="Paul's commentary",
pub_date=datetime.date(2011, 5, 7),
reporter_id=self.r2.id,
)
self.assertEqual(a3.reporter.id, self.r2.id)
# Get should respect explicit foreign keys as well.
msg = "get() returned more than one Article -- it returned 2!"
with self.assertRaisesMessage(MultipleObjectsReturned, msg):
Article.objects.get(reporter_id=self.r.id)
self.assertEqual(
repr(a3),
repr(
Article.objects.get(
reporter_id=self.r2.id, pub_date=datetime.date(2011, 5, 7)
)
),
)
def test_deepcopy_and_circular_references(self):
# Regression for #12876 -- Model methods that include queries that
# recursive don't cause recursion depth problems under deepcopy.
self.r.cached_query = Article.objects.filter(reporter=self.r)
self.assertEqual(repr(deepcopy(self.r)), "<Reporter: John Smith>")
def test_manager_class_caching(self):
r1 = Reporter.objects.create(first_name="Mike")
r2 = Reporter.objects.create(first_name="John")
# Same twice
self.assertIs(r1.article_set.__class__, r1.article_set.__class__)
# Same as each other
self.assertIs(r1.article_set.__class__, r2.article_set.__class__)
def test_create_relation_with_gettext_lazy(self):
reporter = Reporter.objects.create(
first_name="John", last_name="Smith", email="john.smith@example.com"
)
lazy = gettext_lazy("test")
reporter.article_set.create(headline=lazy, pub_date=datetime.date(2011, 6, 10))
notlazy = str(lazy)
article = reporter.article_set.get()
self.assertEqual(article.headline, notlazy)
def test_values_list_exception(self):
expected_message = (
"Cannot resolve keyword 'notafield' into field. Choices are: %s"
)
reporter_fields = ", ".join(sorted(f.name for f in Reporter._meta.get_fields()))
with self.assertRaisesMessage(FieldError, expected_message % reporter_fields):
Article.objects.values_list("reporter__notafield")
article_fields = ", ".join(
["EXTRA"] + sorted(f.name for f in Article._meta.get_fields())
)
with self.assertRaisesMessage(FieldError, expected_message % article_fields):
Article.objects.extra(select={"EXTRA": "EXTRA_SELECT"}).values_list(
"notafield"
)
def test_fk_assignment_and_related_object_cache(self):
# Tests of ForeignKey assignment and the related-object cache (see #6886).
p = Parent.objects.create(name="Parent")
c = Child.objects.create(name="Child", parent=p)
# Look up the object again so that we get a "fresh" object.
c = Child.objects.get(name="Child")
p = c.parent
# Accessing the related object again returns the exactly same object.
self.assertIs(c.parent, p)
# But if we kill the cache, we get a new object.
del c._state.fields_cache["parent"]
self.assertIsNot(c.parent, p)
# Assigning a new object results in that object getting cached immediately.
p2 = Parent.objects.create(name="Parent 2")
c.parent = p2
self.assertIs(c.parent, p2)
# Assigning None succeeds if field is null=True.
p.bestchild = None
self.assertIsNone(p.bestchild)
# bestchild should still be None after saving.
p.save()
self.assertIsNone(p.bestchild)
# bestchild should still be None after fetching the object again.
p = Parent.objects.get(name="Parent")
self.assertIsNone(p.bestchild)
# Assigning None will not fail: Child.parent is null=False.
setattr(c, "parent", None)
# You also can't assign an object of the wrong type here
msg = (
'Cannot assign "<First: First object (1)>": "Child.parent" must '
'be a "Parent" instance.'
)
with self.assertRaisesMessage(ValueError, msg):
setattr(c, "parent", First(id=1, second=1))
# You can assign None to Child.parent during object creation.
Child(name="xyzzy", parent=None)
# But when trying to save a Child with parent=None, the database will
# raise IntegrityError.
with self.assertRaises(IntegrityError), transaction.atomic():
Child.objects.create(name="xyzzy", parent=None)
# Creation using keyword argument should cache the related object.
p = Parent.objects.get(name="Parent")
c = Child(parent=p)
self.assertIs(c.parent, p)
# Creation using keyword argument and unsaved related instance (#8070).
p = Parent()
msg = (
"save() prohibited to prevent data loss due to unsaved related object "
"'parent'."
)
with self.assertRaisesMessage(ValueError, msg):
Child.objects.create(parent=p)
with self.assertRaisesMessage(ValueError, msg):
ToFieldChild.objects.create(parent=p)
# Creation using attname keyword argument and an id will cause the
# related object to be fetched.
p = Parent.objects.get(name="Parent")
c = Child(parent_id=p.id)
self.assertIsNot(c.parent, p)
self.assertEqual(c.parent, p)
def test_save_parent_after_assign(self):
category = Category(name="cats")
record = Record(category=category)
category.save()
record.save()
category.name = "dogs"
with self.assertNumQueries(0):
self.assertEqual(category.id, record.category_id)
self.assertEqual(category.name, record.category.name)
def test_save_nullable_fk_after_parent(self):
parent = Parent()
child = ChildNullableParent(parent=parent)
parent.save()
child.save()
child.refresh_from_db()
self.assertEqual(child.parent, parent)
def test_save_nullable_fk_after_parent_with_to_field(self):
parent = Parent(name="jeff")
child = ToFieldChild(parent=parent)
parent.save()
child.save()
child.refresh_from_db()
self.assertEqual(child.parent, parent)
self.assertEqual(child.parent_id, parent.name)
def test_save_fk_after_parent_with_non_numeric_pk_set_on_child(self):
parent = ParentStringPrimaryKey()
child = ChildStringPrimaryKeyParent(parent=parent)
child.parent.name = "jeff"
parent.save()
child.save()
child.refresh_from_db()
self.assertEqual(child.parent, parent)
self.assertEqual(child.parent_id, parent.name)
def test_fk_to_bigautofield(self):
ch = City.objects.create(name="Chicago")
District.objects.create(city=ch, name="Far South")
District.objects.create(city=ch, name="North")
ny = City.objects.create(name="New York", id=2**33)
District.objects.create(city=ny, name="Brooklyn")
District.objects.create(city=ny, name="Manhattan")
def test_fk_to_smallautofield(self):
us = Country.objects.create(name="United States")
City.objects.create(country=us, name="Chicago")
City.objects.create(country=us, name="New York")
uk = Country.objects.create(name="United Kingdom", id=2**11)
City.objects.create(country=uk, name="London")
City.objects.create(country=uk, name="Edinburgh")
def test_multiple_foreignkeys(self):
# Test of multiple ForeignKeys to the same model (bug #7125).
c1 = Category.objects.create(name="First")
c2 = Category.objects.create(name="Second")
c3 = Category.objects.create(name="Third")
r1 = Record.objects.create(category=c1)
r2 = Record.objects.create(category=c1)
r3 = Record.objects.create(category=c2)
r4 = Record.objects.create(category=c2)
r5 = Record.objects.create(category=c3)
Relation.objects.create(left=r1, right=r2)
Relation.objects.create(left=r3, right=r4)
rel = Relation.objects.create(left=r1, right=r3)
Relation.objects.create(left=r5, right=r2)
Relation.objects.create(left=r3, right=r2)
q1 = Relation.objects.filter(
left__category__name__in=["First"], right__category__name__in=["Second"]
)
self.assertSequenceEqual(q1, [rel])
q2 = Category.objects.filter(
record__left_set__right__category__name="Second"
).order_by("name")
self.assertSequenceEqual(q2, [c1, c2])
p = Parent.objects.create(name="Parent")
c = Child.objects.create(name="Child", parent=p)
msg = 'Cannot assign "%r": "Child.parent" must be a "Parent" instance.' % c
with self.assertRaisesMessage(ValueError, msg):
Child.objects.create(name="Grandchild", parent=c)
def test_fk_instantiation_outside_model(self):
# Regression for #12190 -- Should be able to instantiate a FK outside
# of a model, and interrogate its related field.
cat = models.ForeignKey(Category, models.CASCADE)
self.assertEqual("id", cat.remote_field.get_related_field().name)
def test_relation_unsaved(self):
Third.objects.create(name="Third 1")
Third.objects.create(name="Third 2")
th = Third(name="testing")
# The object isn't saved and the relation cannot be used.
msg = (
"'Third' instance needs to have a primary key value before this "
"relationship can be used."
)
with self.assertRaisesMessage(ValueError, msg):
th.child_set.count()
th.save()
# Now the model is saved, so we will need to execute a query.
with self.assertNumQueries(1):
self.assertEqual(th.child_set.count(), 0)
def test_related_object(self):
public_school = School.objects.create(is_public=True)
public_student = Student.objects.create(school=public_school)
private_school = School.objects.create(is_public=False)
private_student = Student.objects.create(school=private_school)
# Only one school is available via all() due to the custom default manager.
self.assertSequenceEqual(School.objects.all(), [public_school])
self.assertEqual(public_student.school, public_school)
# Make sure the base manager is used so that a student can still access
# its related school even if the default manager doesn't normally
# allow it.
self.assertEqual(private_student.school, private_school)
School._meta.base_manager_name = "objects"
School._meta._expire_cache()
try:
private_student = Student.objects.get(pk=private_student.pk)
with self.assertRaises(School.DoesNotExist):
private_student.school
finally:
School._meta.base_manager_name = None
School._meta._expire_cache()
def test_hasattr_related_object(self):
# The exception raised on attribute access when a related object
# doesn't exist should be an instance of a subclass of `AttributeError`
# refs #21563
self.assertFalse(hasattr(Article(), "reporter"))
def test_clear_after_prefetch(self):
c = City.objects.create(name="Musical City")
d = District.objects.create(name="Ladida", city=c)
city = City.objects.prefetch_related("districts").get(id=c.id)
self.assertSequenceEqual(city.districts.all(), [d])
city.districts.clear()
self.assertSequenceEqual(city.districts.all(), [])
def test_remove_after_prefetch(self):
c = City.objects.create(name="Musical City")
d = District.objects.create(name="Ladida", city=c)
city = City.objects.prefetch_related("districts").get(id=c.id)
self.assertSequenceEqual(city.districts.all(), [d])
city.districts.remove(d)
self.assertSequenceEqual(city.districts.all(), [])
def test_add_after_prefetch(self):
c = City.objects.create(name="Musical City")
District.objects.create(name="Ladida", city=c)
d2 = District.objects.create(name="Ladidu")
city = City.objects.prefetch_related("districts").get(id=c.id)
self.assertEqual(city.districts.count(), 1)
city.districts.add(d2)
self.assertEqual(city.districts.count(), 2)
def test_set_after_prefetch(self):
c = City.objects.create(name="Musical City")
District.objects.create(name="Ladida", city=c)
d2 = District.objects.create(name="Ladidu")
city = City.objects.prefetch_related("districts").get(id=c.id)
self.assertEqual(city.districts.count(), 1)
city.districts.set([d2])
self.assertSequenceEqual(city.districts.all(), [d2])
def test_add_then_remove_after_prefetch(self):
c = City.objects.create(name="Musical City")
District.objects.create(name="Ladida", city=c)
d2 = District.objects.create(name="Ladidu")
city = City.objects.prefetch_related("districts").get(id=c.id)
self.assertEqual(city.districts.count(), 1)
city.districts.add(d2)
self.assertEqual(city.districts.count(), 2)
city.districts.remove(d2)
self.assertEqual(city.districts.count(), 1)
def test_cached_relation_invalidated_on_save(self):
"""
Model.save() invalidates stale ForeignKey relations after a primary key
assignment.
"""
self.assertEqual(self.a.reporter, self.r) # caches a.reporter
self.a.reporter_id = self.r2.pk
self.a.save()
self.assertEqual(self.a.reporter, self.r2)
def test_cached_foreign_key_with_to_field_not_cleared_by_save(self):
parent = Parent.objects.create(name="a")
child = ToFieldChild.objects.create(parent=parent)
with self.assertNumQueries(0):
self.assertIs(child.parent, parent)
def test_reverse_foreign_key_instance_to_field_caching(self):
parent = Parent.objects.create(name="a")
ToFieldChild.objects.create(parent=parent)
child = parent.to_field_children.get()
with self.assertNumQueries(0):
self.assertIs(child.parent, parent)
def test_add_remove_set_by_pk_raises(self):
usa = Country.objects.create(name="United States")
chicago = City.objects.create(name="Chicago")
msg = "'City' instance expected, got %s" % chicago.pk
with self.assertRaisesMessage(TypeError, msg):
usa.cities.add(chicago.pk)
with self.assertRaisesMessage(TypeError, msg):
usa.cities.remove(chicago.pk)
with self.assertRaisesMessage(TypeError, msg):
usa.cities.set([chicago.pk])