django1/tests/model_fields/test_foreignkey.py

159 lines
5.6 KiB
Python

from decimal import Decimal
from django.apps import apps
from django.core import checks
from django.core.exceptions import FieldError
from django.db import models
from django.test import TestCase, skipIfDBFeature
from django.test.utils import isolate_apps
from .models import Bar, FkToChar, Foo, PrimaryKeyCharModel
class ForeignKeyTests(TestCase):
def test_callable_default(self):
"""A lazy callable may be used for ForeignKey.default."""
a = Foo.objects.create(id=1, a='abc', d=Decimal('12.34'))
b = Bar.objects.create(b='bcd')
self.assertEqual(b.a, a)
@skipIfDBFeature('interprets_empty_strings_as_nulls')
def test_empty_string_fk(self):
"""
Empty strings foreign key values don't get converted to None (#19299).
"""
char_model_empty = PrimaryKeyCharModel.objects.create(string='')
fk_model_empty = FkToChar.objects.create(out=char_model_empty)
fk_model_empty = FkToChar.objects.select_related('out').get(id=fk_model_empty.pk)
self.assertEqual(fk_model_empty.out, char_model_empty)
@isolate_apps('model_fields')
def test_warning_when_unique_true_on_fk(self):
class Foo(models.Model):
pass
class FKUniqueTrue(models.Model):
fk_field = models.ForeignKey(Foo, models.CASCADE, unique=True)
model = FKUniqueTrue()
expected_warnings = [
checks.Warning(
'Setting unique=True on a ForeignKey has the same effect as using a OneToOneField.',
hint='ForeignKey(unique=True) is usually better served by a OneToOneField.',
obj=FKUniqueTrue.fk_field.field,
id='fields.W342',
)
]
warnings = model.check()
self.assertEqual(warnings, expected_warnings)
def test_related_name_converted_to_text(self):
rel_name = Bar._meta.get_field('a').remote_field.related_name
self.assertIsInstance(rel_name, str)
def test_abstract_model_pending_operations(self):
"""
Foreign key fields declared on abstract models should not add lazy
relations to resolve relationship declared as string (#24215).
"""
pending_ops_before = list(apps._pending_operations.items())
class AbstractForeignKeyModel(models.Model):
fk = models.ForeignKey('missing.FK', models.CASCADE)
class Meta:
abstract = True
self.assertIs(AbstractForeignKeyModel._meta.apps, apps)
self.assertEqual(
pending_ops_before,
list(apps._pending_operations.items()),
'Pending lookup added for a foreign key on an abstract model'
)
@isolate_apps('model_fields', 'model_fields.tests')
def test_abstract_model_app_relative_foreign_key(self):
class AbstractReferent(models.Model):
reference = models.ForeignKey('Referred', on_delete=models.CASCADE)
class Meta:
app_label = 'model_fields'
abstract = True
def assert_app_model_resolved(label):
class Referred(models.Model):
class Meta:
app_label = label
class ConcreteReferent(AbstractReferent):
class Meta:
app_label = label
self.assertEqual(ConcreteReferent._meta.get_field('reference').related_model, Referred)
assert_app_model_resolved('model_fields')
assert_app_model_resolved('tests')
@isolate_apps('model_fields')
def test_to_python(self):
class Foo(models.Model):
pass
class Bar(models.Model):
fk = models.ForeignKey(Foo, models.CASCADE)
self.assertEqual(Bar._meta.get_field('fk').to_python('1'), 1)
@isolate_apps('model_fields')
def test_fk_to_fk_get_col_output_field(self):
class Foo(models.Model):
pass
class Bar(models.Model):
foo = models.ForeignKey(Foo, models.CASCADE, primary_key=True)
class Baz(models.Model):
bar = models.ForeignKey(Bar, models.CASCADE, primary_key=True)
col = Baz._meta.get_field('bar').get_col('alias')
self.assertIs(col.output_field, Foo._meta.pk)
@isolate_apps('model_fields')
def test_recursive_fks_get_col(self):
class Foo(models.Model):
bar = models.ForeignKey('Bar', models.CASCADE, primary_key=True)
class Bar(models.Model):
foo = models.ForeignKey(Foo, models.CASCADE, primary_key=True)
with self.assertRaisesMessage(ValueError, 'Cannot resolve output_field'):
Foo._meta.get_field('bar').get_col('alias')
@isolate_apps('model_fields')
def test_non_local_to_field(self):
class Parent(models.Model):
key = models.IntegerField(unique=True)
class Child(Parent):
pass
class Related(models.Model):
child = models.ForeignKey(Child, on_delete=models.CASCADE, to_field='key')
msg = (
"'model_fields.Related.child' refers to field 'key' which is not "
"local to model 'model_fields.Child'."
)
with self.assertRaisesMessage(FieldError, msg):
Related._meta.get_field('child').related_fields
def test_invalid_to_parameter(self):
msg = (
"ForeignKey(1) is invalid. First parameter to ForeignKey must be "
"either a model, a model name, or the string 'self'"
)
with self.assertRaisesMessage(TypeError, msg):
class MyModel(models.Model):
child = models.ForeignKey(1, models.CASCADE)