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django/tests/field_defaults/tests.py
Ian Foote 7414704e88 Fixed #470 -- Added support for database defaults on fields.
Special thanks to Hannes Ljungberg for finding multiple implementation
gaps.

Thanks also to Simon Charette, Adam Johnson, and Mariusz Felisiak for
reviews.
2023-05-12 19:11:40 +02:00

205 lines
7.4 KiB
Python

from datetime import datetime
from math import pi
from django.db import connection
from django.db.models import Case, F, FloatField, Value, When
from django.db.models.expressions import (
Expression,
ExpressionList,
ExpressionWrapper,
Func,
OrderByList,
RawSQL,
)
from django.db.models.functions import Collate
from django.db.models.lookups import GreaterThan
from django.test import SimpleTestCase, TestCase, skipIfDBFeature, skipUnlessDBFeature
from .models import (
Article,
DBArticle,
DBDefaults,
DBDefaultsFK,
DBDefaultsFunction,
DBDefaultsPK,
)
class DefaultTests(TestCase):
def test_field_defaults(self):
a = Article()
now = datetime.now()
a.save()
self.assertIsInstance(a.id, int)
self.assertEqual(a.headline, "Default headline")
self.assertLess((now - a.pub_date).seconds, 5)
@skipUnlessDBFeature(
"can_return_columns_from_insert", "supports_expression_defaults"
)
def test_field_db_defaults_returning(self):
a = DBArticle()
a.save()
self.assertIsInstance(a.id, int)
self.assertEqual(a.headline, "Default headline")
self.assertIsInstance(a.pub_date, datetime)
@skipIfDBFeature("can_return_columns_from_insert")
@skipUnlessDBFeature("supports_expression_defaults")
def test_field_db_defaults_refresh(self):
a = DBArticle()
a.save()
a.refresh_from_db()
self.assertIsInstance(a.id, int)
self.assertEqual(a.headline, "Default headline")
self.assertIsInstance(a.pub_date, datetime)
def test_null_db_default(self):
obj1 = DBDefaults.objects.create()
if not connection.features.can_return_columns_from_insert:
obj1.refresh_from_db()
self.assertEqual(obj1.null, 1.1)
obj2 = DBDefaults.objects.create(null=None)
self.assertIsNone(obj2.null)
@skipUnlessDBFeature("supports_expression_defaults")
def test_db_default_function(self):
m = DBDefaultsFunction.objects.create()
if not connection.features.can_return_columns_from_insert:
m.refresh_from_db()
self.assertAlmostEqual(m.number, pi)
self.assertEqual(m.year, datetime.now().year)
self.assertAlmostEqual(m.added, pi + 4.5)
self.assertEqual(m.multiple_subfunctions, 4.5)
@skipUnlessDBFeature("insert_test_table_with_defaults")
def test_both_default(self):
create_sql = connection.features.insert_test_table_with_defaults
with connection.cursor() as cursor:
cursor.execute(create_sql.format(DBDefaults._meta.db_table))
obj1 = DBDefaults.objects.get()
self.assertEqual(obj1.both, 2)
obj2 = DBDefaults.objects.create()
self.assertEqual(obj2.both, 1)
def test_pk_db_default(self):
obj1 = DBDefaultsPK.objects.create()
if not connection.features.can_return_columns_from_insert:
# refresh_from_db() cannot be used because that needs the pk to
# already be known to Django.
obj1 = DBDefaultsPK.objects.get(pk="en")
self.assertEqual(obj1.pk, "en")
self.assertEqual(obj1.language_code, "en")
obj2 = DBDefaultsPK.objects.create(language_code="de")
self.assertEqual(obj2.pk, "de")
self.assertEqual(obj2.language_code, "de")
def test_foreign_key_db_default(self):
parent1 = DBDefaultsPK.objects.create(language_code="fr")
child1 = DBDefaultsFK.objects.create()
if not connection.features.can_return_columns_from_insert:
child1.refresh_from_db()
self.assertEqual(child1.language_code, parent1)
parent2 = DBDefaultsPK.objects.create()
if not connection.features.can_return_columns_from_insert:
# refresh_from_db() cannot be used because that needs the pk to
# already be known to Django.
parent2 = DBDefaultsPK.objects.get(pk="en")
child2 = DBDefaultsFK.objects.create(language_code=parent2)
self.assertEqual(child2.language_code, parent2)
@skipUnlessDBFeature(
"can_return_columns_from_insert", "supports_expression_defaults"
)
def test_case_when_db_default_returning(self):
m = DBDefaultsFunction.objects.create()
self.assertEqual(m.case_when, 3)
@skipIfDBFeature("can_return_columns_from_insert")
@skipUnlessDBFeature("supports_expression_defaults")
def test_case_when_db_default_no_returning(self):
m = DBDefaultsFunction.objects.create()
m.refresh_from_db()
self.assertEqual(m.case_when, 3)
@skipUnlessDBFeature("supports_expression_defaults")
def test_bulk_create_all_db_defaults(self):
articles = [DBArticle(), DBArticle()]
DBArticle.objects.bulk_create(articles)
headlines = DBArticle.objects.values_list("headline", flat=True)
self.assertSequenceEqual(headlines, ["Default headline", "Default headline"])
@skipUnlessDBFeature("supports_expression_defaults")
def test_bulk_create_all_db_defaults_one_field(self):
pub_date = datetime.now()
articles = [DBArticle(pub_date=pub_date), DBArticle(pub_date=pub_date)]
DBArticle.objects.bulk_create(articles)
headlines = DBArticle.objects.values_list("headline", "pub_date")
self.assertSequenceEqual(
headlines,
[
("Default headline", pub_date),
("Default headline", pub_date),
],
)
@skipUnlessDBFeature("supports_expression_defaults")
def test_bulk_create_mixed_db_defaults(self):
articles = [DBArticle(), DBArticle(headline="Something else")]
DBArticle.objects.bulk_create(articles)
headlines = DBArticle.objects.values_list("headline", flat=True)
self.assertCountEqual(headlines, ["Default headline", "Something else"])
@skipUnlessDBFeature("supports_expression_defaults")
def test_bulk_create_mixed_db_defaults_function(self):
instances = [DBDefaultsFunction(), DBDefaultsFunction(year=2000)]
DBDefaultsFunction.objects.bulk_create(instances)
years = DBDefaultsFunction.objects.values_list("year", flat=True)
self.assertCountEqual(years, [2000, datetime.now().year])
class AllowedDefaultTests(SimpleTestCase):
def test_allowed(self):
class Max(Func):
function = "MAX"
tests = [
Value(10),
Max(1, 2),
RawSQL("Now()", ()),
Value(10) + Value(7), # Combined expression.
ExpressionList(Value(1), Value(2)),
ExpressionWrapper(Value(1), output_field=FloatField()),
Case(When(GreaterThan(2, 1), then=3), default=4),
]
for expression in tests:
with self.subTest(expression=expression):
self.assertIs(expression.allowed_default, True)
def test_disallowed(self):
class Max(Func):
function = "MAX"
tests = [
Expression(),
F("field"),
Max(F("count"), 1),
Value(10) + F("count"), # Combined expression.
ExpressionList(F("count"), Value(2)),
ExpressionWrapper(F("count"), output_field=FloatField()),
Collate(Value("John"), "nocase"),
OrderByList("field"),
]
for expression in tests:
with self.subTest(expression=expression):
self.assertIs(expression.allowed_default, False)