django/tests/basic/tests.py

738 lines
28 KiB
Python

import threading
from datetime import datetime, timedelta
from django.core.exceptions import MultipleObjectsReturned, ObjectDoesNotExist
from django.db import DEFAULT_DB_ALIAS, DatabaseError, connections
from django.db.models.manager import BaseManager
from django.db.models.query import EmptyQuerySet, QuerySet
from django.test import (
SimpleTestCase, TestCase, TransactionTestCase, skipUnlessDBFeature,
)
from django.utils.translation import gettext_lazy
from .models import Article, ArticleSelectOnSave, FeaturedArticle, SelfRef
class ModelInstanceCreationTests(TestCase):
def test_object_is_not_written_to_database_until_save_was_called(self):
a = Article(
id=None,
headline='Parrot programs in Python',
pub_date=datetime(2005, 7, 28),
)
self.assertIsNone(a.id)
self.assertEqual(Article.objects.all().count(), 0)
# Save it into the database. You have to call save() explicitly.
a.save()
self.assertIsNotNone(a.id)
self.assertEqual(Article.objects.all().count(), 1)
def test_can_initialize_model_instance_using_positional_arguments(self):
"""
You can initialize a model instance using positional arguments,
which should match the field order as defined in the model.
"""
a = Article(None, 'Second article', datetime(2005, 7, 29))
a.save()
self.assertEqual(a.headline, 'Second article')
self.assertEqual(a.pub_date, datetime(2005, 7, 29, 0, 0))
def test_can_create_instance_using_kwargs(self):
a = Article(
id=None,
headline='Third article',
pub_date=datetime(2005, 7, 30),
)
a.save()
self.assertEqual(a.headline, 'Third article')
self.assertEqual(a.pub_date, datetime(2005, 7, 30, 0, 0))
def test_autofields_generate_different_values_for_each_instance(self):
a1 = Article.objects.create(headline='First', pub_date=datetime(2005, 7, 30, 0, 0))
a2 = Article.objects.create(headline='First', pub_date=datetime(2005, 7, 30, 0, 0))
a3 = Article.objects.create(headline='First', pub_date=datetime(2005, 7, 30, 0, 0))
self.assertNotEqual(a3.id, a1.id)
self.assertNotEqual(a3.id, a2.id)
def test_can_mix_and_match_position_and_kwargs(self):
# You can also mix and match position and keyword arguments, but
# be sure not to duplicate field information.
a = Article(None, 'Fourth article', pub_date=datetime(2005, 7, 31))
a.save()
self.assertEqual(a.headline, 'Fourth article')
def test_cannot_create_instance_with_invalid_kwargs(self):
with self.assertRaisesMessage(TypeError, "'foo' is an invalid keyword argument for this function"):
Article(
id=None,
headline='Some headline',
pub_date=datetime(2005, 7, 31),
foo='bar',
)
def test_can_leave_off_value_for_autofield_and_it_gets_value_on_save(self):
"""
You can leave off the value for an AutoField when creating an
object, because it'll get filled in automatically when you save().
"""
a = Article(headline='Article 5', pub_date=datetime(2005, 7, 31))
a.save()
self.assertEqual(a.headline, 'Article 5')
self.assertIsNotNone(a.id)
def test_leaving_off_a_field_with_default_set_the_default_will_be_saved(self):
a = Article(pub_date=datetime(2005, 7, 31))
a.save()
self.assertEqual(a.headline, 'Default headline')
def test_for_datetimefields_saves_as_much_precision_as_was_given(self):
"""as much precision in *seconds*"""
a1 = Article(
headline='Article 7',
pub_date=datetime(2005, 7, 31, 12, 30),
)
a1.save()
self.assertEqual(Article.objects.get(id__exact=a1.id).pub_date, datetime(2005, 7, 31, 12, 30))
a2 = Article(
headline='Article 8',
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
a2.save()
self.assertEqual(Article.objects.get(id__exact=a2.id).pub_date, datetime(2005, 7, 31, 12, 30, 45))
def test_saving_an_object_again_does_not_create_a_new_object(self):
a = Article(headline='original', pub_date=datetime(2014, 5, 16))
a.save()
current_id = a.id
a.save()
self.assertEqual(a.id, current_id)
a.headline = 'Updated headline'
a.save()
self.assertEqual(a.id, current_id)
def test_querysets_checking_for_membership(self):
headlines = [
'Parrot programs in Python', 'Second article', 'Third article']
some_pub_date = datetime(2014, 5, 16, 12, 1)
for headline in headlines:
Article(headline=headline, pub_date=some_pub_date).save()
a = Article(headline='Some headline', pub_date=some_pub_date)
a.save()
# You can use 'in' to test for membership...
self.assertIn(a, Article.objects.all())
# ... but there will often be more efficient ways if that is all you need:
self.assertTrue(Article.objects.filter(id=a.id).exists())
class ModelTest(TestCase):
def test_objects_attribute_is_only_available_on_the_class_itself(self):
with self.assertRaisesMessage(AttributeError, "Manager isn't accessible via Article instances"):
getattr(Article(), "objects",)
self.assertFalse(hasattr(Article(), 'objects'))
self.assertTrue(hasattr(Article, 'objects'))
def test_queryset_delete_removes_all_items_in_that_queryset(self):
headlines = [
'An article', 'Article One', 'Amazing article', 'Boring article']
some_pub_date = datetime(2014, 5, 16, 12, 1)
for headline in headlines:
Article(headline=headline, pub_date=some_pub_date).save()
self.assertQuerysetEqual(
Article.objects.all().order_by('headline'),
["<Article: Amazing article>",
"<Article: An article>",
"<Article: Article One>",
"<Article: Boring article>"]
)
Article.objects.filter(headline__startswith='A').delete()
self.assertQuerysetEqual(Article.objects.all().order_by('headline'), ["<Article: Boring article>"])
def test_not_equal_and_equal_operators_behave_as_expected_on_instances(self):
some_pub_date = datetime(2014, 5, 16, 12, 1)
a1 = Article.objects.create(headline='First', pub_date=some_pub_date)
a2 = Article.objects.create(headline='Second', pub_date=some_pub_date)
self.assertNotEqual(a1, a2)
self.assertEqual(a1, Article.objects.get(id__exact=a1.id))
self.assertNotEqual(Article.objects.get(id__exact=a1.id), Article.objects.get(id__exact=a2.id))
def test_microsecond_precision(self):
a9 = Article(
headline='Article 9',
pub_date=datetime(2005, 7, 31, 12, 30, 45, 180),
)
a9.save()
self.assertEqual(Article.objects.get(pk=a9.pk).pub_date, datetime(2005, 7, 31, 12, 30, 45, 180))
def test_manually_specify_primary_key(self):
# You can manually specify the primary key when creating a new object.
a101 = Article(
id=101,
headline='Article 101',
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
a101.save()
a101 = Article.objects.get(pk=101)
self.assertEqual(a101.headline, 'Article 101')
def test_create_method(self):
# You can create saved objects in a single step
a10 = Article.objects.create(
headline="Article 10",
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
self.assertEqual(Article.objects.get(headline="Article 10"), a10)
def test_year_lookup_edge_case(self):
# Edge-case test: A year lookup should retrieve all objects in
# the given year, including Jan. 1 and Dec. 31.
Article.objects.create(
headline='Article 11',
pub_date=datetime(2008, 1, 1),
)
Article.objects.create(
headline='Article 12',
pub_date=datetime(2008, 12, 31, 23, 59, 59, 999999),
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__year=2008),
["<Article: Article 11>", "<Article: Article 12>"]
)
def test_unicode_data(self):
# Unicode data works, too.
a = Article(
headline='\u6797\u539f \u3081\u3050\u307f',
pub_date=datetime(2005, 7, 28),
)
a.save()
self.assertEqual(Article.objects.get(pk=a.id).headline, '\u6797\u539f \u3081\u3050\u307f')
def test_hash_function(self):
# Model instances have a hash function, so they can be used in sets
# or as dictionary keys. Two models compare as equal if their primary
# keys are equal.
a10 = Article.objects.create(
headline="Article 10",
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
a11 = Article.objects.create(
headline='Article 11',
pub_date=datetime(2008, 1, 1),
)
a12 = Article.objects.create(
headline='Article 12',
pub_date=datetime(2008, 12, 31, 23, 59, 59, 999999),
)
s = {a10, a11, a12}
self.assertIn(Article.objects.get(headline='Article 11'), s)
def test_extra_method_select_argument_with_dashes_and_values(self):
# The 'select' argument to extra() supports names with dashes in
# them, as long as you use values().
Article.objects.create(
headline="Article 10",
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
Article.objects.create(
headline='Article 11',
pub_date=datetime(2008, 1, 1),
)
Article.objects.create(
headline='Article 12',
pub_date=datetime(2008, 12, 31, 23, 59, 59, 999999),
)
dicts = Article.objects.filter(
pub_date__year=2008).extra(
select={'dashed-value': '1'}).values('headline', 'dashed-value')
self.assertEqual(
[sorted(d.items()) for d in dicts],
[[('dashed-value', 1), ('headline', 'Article 11')], [('dashed-value', 1), ('headline', 'Article 12')]]
)
def test_extra_method_select_argument_with_dashes(self):
# If you use 'select' with extra() and names containing dashes on a
# query that's *not* a values() query, those extra 'select' values
# will silently be ignored.
Article.objects.create(
headline="Article 10",
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
Article.objects.create(
headline='Article 11',
pub_date=datetime(2008, 1, 1),
)
Article.objects.create(
headline='Article 12',
pub_date=datetime(2008, 12, 31, 23, 59, 59, 999999),
)
articles = Article.objects.filter(
pub_date__year=2008).extra(select={'dashed-value': '1', 'undashedvalue': '2'})
self.assertEqual(articles[0].undashedvalue, 2)
def test_create_relation_with_gettext_lazy(self):
"""
gettext_lazy objects work when saving model instances
through various methods. Refs #10498.
"""
notlazy = 'test'
lazy = gettext_lazy(notlazy)
Article.objects.create(headline=lazy, pub_date=datetime.now())
article = Article.objects.get()
self.assertEqual(article.headline, notlazy)
# test that assign + save works with Promise objects
article.headline = lazy
article.save()
self.assertEqual(article.headline, notlazy)
# test .update()
Article.objects.update(headline=lazy)
article = Article.objects.get()
self.assertEqual(article.headline, notlazy)
# still test bulk_create()
Article.objects.all().delete()
Article.objects.bulk_create([Article(headline=lazy, pub_date=datetime.now())])
article = Article.objects.get()
self.assertEqual(article.headline, notlazy)
def test_emptyqs(self):
msg = "EmptyQuerySet can't be instantiated"
with self.assertRaisesMessage(TypeError, msg):
EmptyQuerySet()
self.assertIsInstance(Article.objects.none(), EmptyQuerySet)
self.assertNotIsInstance('', EmptyQuerySet)
def test_emptyqs_values(self):
# test for #15959
Article.objects.create(headline='foo', pub_date=datetime.now())
with self.assertNumQueries(0):
qs = Article.objects.none().values_list('pk')
self.assertIsInstance(qs, EmptyQuerySet)
self.assertEqual(len(qs), 0)
def test_emptyqs_customqs(self):
# A hacky test for custom QuerySet subclass - refs #17271
Article.objects.create(headline='foo', pub_date=datetime.now())
class CustomQuerySet(QuerySet):
def do_something(self):
return 'did something'
qs = Article.objects.all()
qs.__class__ = CustomQuerySet
qs = qs.none()
with self.assertNumQueries(0):
self.assertEqual(len(qs), 0)
self.assertIsInstance(qs, EmptyQuerySet)
self.assertEqual(qs.do_something(), 'did something')
def test_emptyqs_values_order(self):
# Tests for ticket #17712
Article.objects.create(headline='foo', pub_date=datetime.now())
with self.assertNumQueries(0):
self.assertEqual(len(Article.objects.none().values_list('id').order_by('id')), 0)
with self.assertNumQueries(0):
self.assertEqual(len(Article.objects.none().filter(
id__in=Article.objects.values_list('id', flat=True))), 0)
@skipUnlessDBFeature('can_distinct_on_fields')
def test_emptyqs_distinct(self):
# Tests for #19426
Article.objects.create(headline='foo', pub_date=datetime.now())
with self.assertNumQueries(0):
self.assertEqual(len(Article.objects.none().distinct('headline', 'pub_date')), 0)
def test_ticket_20278(self):
sr = SelfRef.objects.create()
with self.assertRaises(ObjectDoesNotExist):
SelfRef.objects.get(selfref=sr)
def test_eq(self):
self.assertEqual(Article(id=1), Article(id=1))
self.assertNotEqual(Article(id=1), object())
self.assertNotEqual(object(), Article(id=1))
a = Article()
self.assertEqual(a, a)
self.assertNotEqual(Article(), a)
def test_hash(self):
# Value based on PK
self.assertEqual(hash(Article(id=1)), hash(1))
msg = 'Model instances without primary key value are unhashable'
with self.assertRaisesMessage(TypeError, msg):
# No PK value -> unhashable (because save() would then change
# hash)
hash(Article())
def test_delete_and_access_field(self):
# Accessing a field after it's deleted from a model reloads its value.
pub_date = datetime.now()
article = Article.objects.create(headline='foo', pub_date=pub_date)
new_pub_date = article.pub_date + timedelta(days=10)
article.headline = 'bar'
article.pub_date = new_pub_date
del article.headline
with self.assertNumQueries(1):
self.assertEqual(article.headline, 'foo')
# Fields that weren't deleted aren't reloaded.
self.assertEqual(article.pub_date, new_pub_date)
class ModelLookupTest(TestCase):
def setUp(self):
# Create an Article.
self.a = Article(
id=None,
headline='Swallow programs in Python',
pub_date=datetime(2005, 7, 28),
)
# Save it into the database. You have to call save() explicitly.
self.a.save()
def test_all_lookup(self):
# Change values by changing the attributes, then calling save().
self.a.headline = 'Parrot programs in Python'
self.a.save()
# Article.objects.all() returns all the articles in the database.
self.assertQuerysetEqual(Article.objects.all(), ['<Article: Parrot programs in Python>'])
def test_rich_lookup(self):
# Django provides a rich database lookup API.
self.assertEqual(Article.objects.get(id__exact=self.a.id), self.a)
self.assertEqual(Article.objects.get(headline__startswith='Swallow'), self.a)
self.assertEqual(Article.objects.get(pub_date__year=2005), self.a)
self.assertEqual(Article.objects.get(pub_date__year=2005, pub_date__month=7), self.a)
self.assertEqual(Article.objects.get(pub_date__year=2005, pub_date__month=7, pub_date__day=28), self.a)
self.assertEqual(Article.objects.get(pub_date__week_day=5), self.a)
def test_equal_lookup(self):
# The "__exact" lookup type can be omitted, as a shortcut.
self.assertEqual(Article.objects.get(id=self.a.id), self.a)
self.assertEqual(Article.objects.get(headline='Swallow programs in Python'), self.a)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__year=2005),
['<Article: Swallow programs in Python>'],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__year=2004),
[],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__year=2005, pub_date__month=7),
['<Article: Swallow programs in Python>'],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__week_day=5),
['<Article: Swallow programs in Python>'],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__week_day=6),
[],
)
def test_does_not_exist(self):
# Django raises an Article.DoesNotExist exception for get() if the
# parameters don't match any object.
with self.assertRaisesMessage(ObjectDoesNotExist, "Article matching query does not exist."):
Article.objects.get(id__exact=2000,)
# To avoid dict-ordering related errors check only one lookup
# in single assert.
with self.assertRaises(ObjectDoesNotExist):
Article.objects.get(pub_date__year=2005, pub_date__month=8)
with self.assertRaisesMessage(ObjectDoesNotExist, "Article matching query does not exist."):
Article.objects.get(pub_date__week_day=6,)
def test_lookup_by_primary_key(self):
# Lookup by a primary key is the most common case, so Django
# provides a shortcut for primary-key exact lookups.
# The following is identical to articles.get(id=a.id).
self.assertEqual(Article.objects.get(pk=self.a.id), self.a)
# pk can be used as a shortcut for the primary key name in any query.
self.assertQuerysetEqual(Article.objects.filter(pk__in=[self.a.id]), ["<Article: Swallow programs in Python>"])
# Model instances of the same type and same ID are considered equal.
a = Article.objects.get(pk=self.a.id)
b = Article.objects.get(pk=self.a.id)
self.assertEqual(a, b)
def test_too_many(self):
# Create a very similar object
a = Article(
id=None,
headline='Swallow bites Python',
pub_date=datetime(2005, 7, 28),
)
a.save()
self.assertEqual(Article.objects.count(), 2)
# Django raises an Article.MultipleObjectsReturned exception if the
# lookup matches more than one object
msg = "get() returned more than one Article -- it returned 2!"
with self.assertRaisesMessage(MultipleObjectsReturned, msg):
Article.objects.get(headline__startswith='Swallow',)
with self.assertRaisesMessage(MultipleObjectsReturned, msg):
Article.objects.get(pub_date__year=2005,)
with self.assertRaisesMessage(MultipleObjectsReturned, msg):
Article.objects.get(pub_date__year=2005, pub_date__month=7)
class ConcurrentSaveTests(TransactionTestCase):
available_apps = ['basic']
@skipUnlessDBFeature('test_db_allows_multiple_connections')
def test_concurrent_delete_with_save(self):
"""
Test fetching, deleting and finally saving an object - we should get
an insert in this case.
"""
a = Article.objects.create(headline='foo', pub_date=datetime.now())
exceptions = []
def deleter():
try:
# Do not delete a directly - doing so alters its state.
Article.objects.filter(pk=a.pk).delete()
except Exception as e:
exceptions.append(e)
finally:
connections[DEFAULT_DB_ALIAS].close()
self.assertEqual(len(exceptions), 0)
t = threading.Thread(target=deleter)
t.start()
t.join()
a.save()
self.assertEqual(Article.objects.get(pk=a.pk).headline, 'foo')
class ManagerTest(SimpleTestCase):
QUERYSET_PROXY_METHODS = [
'none',
'count',
'dates',
'datetimes',
'distinct',
'extra',
'get',
'get_or_create',
'update_or_create',
'create',
'bulk_create',
'filter',
'aggregate',
'annotate',
'complex_filter',
'exclude',
'in_bulk',
'iterator',
'earliest',
'latest',
'first',
'last',
'order_by',
'select_for_update',
'select_related',
'prefetch_related',
'values',
'values_list',
'update',
'reverse',
'defer',
'only',
'using',
'exists',
'explain',
'_insert',
'_update',
'raw',
'union',
'intersection',
'difference',
]
def test_manager_methods(self):
"""
This test ensures that the correct set of methods from `QuerySet`
are copied onto `Manager`.
It's particularly useful to prevent accidentally leaking new methods
into `Manager`. New `QuerySet` methods that should also be copied onto
`Manager` will need to be added to `ManagerTest.QUERYSET_PROXY_METHODS`.
"""
self.assertEqual(
sorted(BaseManager._get_queryset_methods(QuerySet)),
sorted(self.QUERYSET_PROXY_METHODS),
)
class SelectOnSaveTests(TestCase):
def test_select_on_save(self):
a1 = Article.objects.create(pub_date=datetime.now())
with self.assertNumQueries(1):
a1.save()
asos = ArticleSelectOnSave.objects.create(pub_date=datetime.now())
with self.assertNumQueries(2):
asos.save()
with self.assertNumQueries(1):
asos.save(force_update=True)
Article.objects.all().delete()
with self.assertRaisesMessage(DatabaseError, 'Forced update did not affect any rows.'):
with self.assertNumQueries(1):
asos.save(force_update=True)
def test_select_on_save_lying_update(self):
"""
select_on_save works correctly if the database doesn't return correct
information about matched rows from UPDATE.
"""
# Change the manager to not return "row matched" for update().
# We are going to change the Article's _base_manager class
# dynamically. This is a bit of a hack, but it seems hard to
# test this properly otherwise. Article's manager, because
# proxy models use their parent model's _base_manager.
orig_class = Article._base_manager._queryset_class
class FakeQuerySet(QuerySet):
# Make sure the _update method below is in fact called.
called = False
def _update(self, *args, **kwargs):
FakeQuerySet.called = True
super()._update(*args, **kwargs)
return 0
try:
Article._base_manager._queryset_class = FakeQuerySet
asos = ArticleSelectOnSave.objects.create(pub_date=datetime.now())
with self.assertNumQueries(3):
asos.save()
self.assertTrue(FakeQuerySet.called)
# This is not wanted behavior, but this is how Django has always
# behaved for databases that do not return correct information
# about matched rows for UPDATE.
with self.assertRaisesMessage(DatabaseError, 'Forced update did not affect any rows.'):
asos.save(force_update=True)
msg = (
"An error occurred in the current transaction. You can't "
"execute queries until the end of the 'atomic' block."
)
with self.assertRaisesMessage(DatabaseError, msg):
asos.save(update_fields=['pub_date'])
finally:
Article._base_manager._queryset_class = orig_class
class ModelRefreshTests(TestCase):
def test_refresh(self):
a = Article.objects.create(pub_date=datetime.now())
Article.objects.create(pub_date=datetime.now())
Article.objects.filter(pk=a.pk).update(headline='new headline')
with self.assertNumQueries(1):
a.refresh_from_db()
self.assertEqual(a.headline, 'new headline')
orig_pub_date = a.pub_date
new_pub_date = a.pub_date + timedelta(10)
Article.objects.update(headline='new headline 2', pub_date=new_pub_date)
with self.assertNumQueries(1):
a.refresh_from_db(fields=['headline'])
self.assertEqual(a.headline, 'new headline 2')
self.assertEqual(a.pub_date, orig_pub_date)
with self.assertNumQueries(1):
a.refresh_from_db()
self.assertEqual(a.pub_date, new_pub_date)
def test_unknown_kwarg(self):
s = SelfRef.objects.create()
msg = "refresh_from_db() got an unexpected keyword argument 'unknown_kwarg'"
with self.assertRaisesMessage(TypeError, msg):
s.refresh_from_db(unknown_kwarg=10)
def test_refresh_fk(self):
s1 = SelfRef.objects.create()
s2 = SelfRef.objects.create()
s3 = SelfRef.objects.create(selfref=s1)
s3_copy = SelfRef.objects.get(pk=s3.pk)
s3_copy.selfref.touched = True
s3.selfref = s2
s3.save()
with self.assertNumQueries(1):
s3_copy.refresh_from_db()
with self.assertNumQueries(1):
# The old related instance was thrown away (the selfref_id has
# changed). It needs to be reloaded on access, so one query
# executed.
self.assertFalse(hasattr(s3_copy.selfref, 'touched'))
self.assertEqual(s3_copy.selfref, s2)
def test_refresh_null_fk(self):
s1 = SelfRef.objects.create()
s2 = SelfRef.objects.create(selfref=s1)
s2.selfref = None
s2.refresh_from_db()
self.assertEqual(s2.selfref, s1)
def test_refresh_unsaved(self):
pub_date = datetime.now()
a = Article.objects.create(pub_date=pub_date)
a2 = Article(id=a.pk)
with self.assertNumQueries(1):
a2.refresh_from_db()
self.assertEqual(a2.pub_date, pub_date)
self.assertEqual(a2._state.db, "default")
def test_refresh_fk_on_delete_set_null(self):
a = Article.objects.create(
headline='Parrot programs in Python',
pub_date=datetime(2005, 7, 28),
)
s1 = SelfRef.objects.create(article=a)
a.delete()
s1.refresh_from_db()
self.assertIsNone(s1.article_id)
self.assertIsNone(s1.article)
def test_refresh_no_fields(self):
a = Article.objects.create(pub_date=datetime.now())
with self.assertNumQueries(0):
a.refresh_from_db(fields=[])
def test_refresh_clears_reverse_related(self):
"""refresh_from_db() clear cached reverse relations."""
article = Article.objects.create(
headline='Parrot programs in Python',
pub_date=datetime(2005, 7, 28),
)
self.assertFalse(hasattr(article, 'featured'))
FeaturedArticle.objects.create(article_id=article.pk)
article.refresh_from_db()
self.assertTrue(hasattr(article, 'featured'))
def test_refresh_clears_one_to_one_field(self):
article = Article.objects.create(
headline='Parrot programs in Python',
pub_date=datetime(2005, 7, 28),
)
featured = FeaturedArticle.objects.create(article_id=article.pk)
self.assertEqual(featured.article.headline, 'Parrot programs in Python')
article.headline = 'Parrot programs in Python 2.0'
article.save()
featured.refresh_from_db()
self.assertEqual(featured.article.headline, 'Parrot programs in Python 2.0')