django/tests/basic/tests.py

737 lines
28 KiB
Python

from __future__ import absolute_import, unicode_literals
from datetime import datetime
import threading
from django.core.exceptions import ObjectDoesNotExist, MultipleObjectsReturned
from django.db import connections, DEFAULT_DB_ALIAS
from django.db.models.fields import Field, FieldDoesNotExist
from django.db.models.query import QuerySet, EmptyQuerySet, ValuesListQuerySet, MAX_GET_RESULTS
from django.test import TestCase, TransactionTestCase, skipIfDBFeature, skipUnlessDBFeature
from django.utils import six
from django.utils.translation import ugettext_lazy
from .models import Article, SelfRef
class ModelTest(TestCase):
def test_lookup(self):
# No articles are in the system yet.
self.assertQuerysetEqual(Article.objects.all(), [])
# Create an Article.
a = Article(
id=None,
headline='Area man programs in Python',
pub_date=datetime(2005, 7, 28),
)
# Save it into the database. You have to call save() explicitly.
a.save()
# Now it has an ID.
self.assertTrue(a.id != None)
# Models have a pk property that is an alias for the primary key
# attribute (by default, the 'id' attribute).
self.assertEqual(a.pk, a.id)
# Access database columns via Python attributes.
self.assertEqual(a.headline, 'Area man programs in Python')
self.assertEqual(a.pub_date, datetime(2005, 7, 28, 0, 0))
# Change values by changing the attributes, then calling save().
a.headline = 'Area woman programs in Python'
a.save()
# Article.objects.all() returns all the articles in the database.
self.assertQuerysetEqual(Article.objects.all(),
['<Article: Area woman programs in Python>'])
# Django provides a rich database lookup API.
self.assertEqual(Article.objects.get(id__exact=a.id), a)
self.assertEqual(Article.objects.get(headline__startswith='Area woman'), a)
self.assertEqual(Article.objects.get(pub_date__year=2005), a)
self.assertEqual(Article.objects.get(pub_date__year=2005, pub_date__month=7), a)
self.assertEqual(Article.objects.get(pub_date__year=2005, pub_date__month=7, pub_date__day=28), a)
self.assertEqual(Article.objects.get(pub_date__week_day=5), a)
# The "__exact" lookup type can be omitted, as a shortcut.
self.assertEqual(Article.objects.get(id=a.id), a)
self.assertEqual(Article.objects.get(headline='Area woman programs in Python'), a)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__year=2005),
['<Article: Area woman 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: Area woman programs in Python>'],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__week_day=5),
['<Article: Area woman programs in Python>'],
)
self.assertQuerysetEqual(
Article.objects.filter(pub_date__week_day=6),
[],
)
# Django raises an Article.DoesNotExist exception for get() if the
# parameters don't match any object.
six.assertRaisesRegex(self,
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.
self.assertRaises(
ObjectDoesNotExist,
Article.objects.get,
pub_date__year=2005,
pub_date__month=8,
)
six.assertRaisesRegex(self,
ObjectDoesNotExist,
"Article matching query does not exist.",
Article.objects.get,
pub_date__week_day=6,
)
# 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=a.id), a)
# pk can be used as a shortcut for the primary key name in any query.
self.assertQuerysetEqual(Article.objects.filter(pk__in=[a.id]),
["<Article: Area woman programs in Python>"])
# Model instances of the same type and same ID are considered equal.
a = Article.objects.get(pk=a.id)
b = Article.objects.get(pk=a.id)
self.assertEqual(a, b)
# Create a very similar object
a = Article(
id=None,
headline='Area man programs in 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
six.assertRaisesRegex(self,
MultipleObjectsReturned,
"get\(\) returned more than one Article -- it returned 2!",
Article.objects.get,
headline__startswith='Area',
)
six.assertRaisesRegex(self,
MultipleObjectsReturned,
"get\(\) returned more than one Article -- it returned 2!",
Article.objects.get,
pub_date__year=2005,
)
six.assertRaisesRegex(self,
MultipleObjectsReturned,
"get\(\) returned more than one Article -- it returned 2!",
Article.objects.get,
pub_date__year=2005,
pub_date__month=7,
)
def test_multiple_objects_max_num_fetched(self):
"""
#6785 - get() should fetch a limited number of results.
"""
Article.objects.bulk_create(
Article(headline='Area %s' % i, pub_date=datetime(2005, 7, 28))
for i in range(MAX_GET_RESULTS)
)
six.assertRaisesRegex(self,
MultipleObjectsReturned,
"get\(\) returned more than one Article -- it returned %d!" % MAX_GET_RESULTS,
Article.objects.get,
headline__startswith='Area',
)
Article.objects.create(headline='Area %s' % MAX_GET_RESULTS, pub_date=datetime(2005, 7, 28))
six.assertRaisesRegex(self,
MultipleObjectsReturned,
"get\(\) returned more than one Article -- it returned more than %d!" % MAX_GET_RESULTS,
Article.objects.get,
headline__startswith='Area',
)
def test_object_creation(self):
# Create an Article.
a = Article(
id=None,
headline='Area man programs in Python',
pub_date=datetime(2005, 7, 28),
)
# Save it into the database. You have to call save() explicitly.
a.save()
# You can initialize a model instance using positional arguments,
# which should match the field order as defined in the model.
a2 = Article(None, 'Second article', datetime(2005, 7, 29))
a2.save()
self.assertNotEqual(a2.id, a.id)
self.assertEqual(a2.headline, 'Second article')
self.assertEqual(a2.pub_date, datetime(2005, 7, 29, 0, 0))
# ...or, you can use keyword arguments.
a3 = Article(
id=None,
headline='Third article',
pub_date=datetime(2005, 7, 30),
)
a3.save()
self.assertNotEqual(a3.id, a.id)
self.assertNotEqual(a3.id, a2.id)
self.assertEqual(a3.headline, 'Third article')
self.assertEqual(a3.pub_date, datetime(2005, 7, 30, 0, 0))
# You can also mix and match position and keyword arguments, but
# be sure not to duplicate field information.
a4 = Article(None, 'Fourth article', pub_date=datetime(2005, 7, 31))
a4.save()
self.assertEqual(a4.headline, 'Fourth article')
# Don't use invalid keyword arguments.
six.assertRaisesRegex(self,
TypeError,
"'foo' is an invalid keyword argument for this function",
Article,
id=None,
headline='Invalid',
pub_date=datetime(2005, 7, 31),
foo='bar',
)
# You can leave off the value for an AutoField when creating an
# object, because it'll get filled in automatically when you save().
a5 = Article(headline='Article 6', pub_date=datetime(2005, 7, 31))
a5.save()
self.assertEqual(a5.headline, 'Article 6')
# If you leave off a field with "default" set, Django will use
# the default.
a6 = Article(pub_date=datetime(2005, 7, 31))
a6.save()
self.assertEqual(a6.headline, 'Default headline')
# For DateTimeFields, Django saves as much precision (in seconds)
# as you give it.
a7 = Article(
headline='Article 7',
pub_date=datetime(2005, 7, 31, 12, 30),
)
a7.save()
self.assertEqual(Article.objects.get(id__exact=a7.id).pub_date,
datetime(2005, 7, 31, 12, 30))
a8 = Article(
headline='Article 8',
pub_date=datetime(2005, 7, 31, 12, 30, 45),
)
a8.save()
self.assertEqual(Article.objects.get(id__exact=a8.id).pub_date,
datetime(2005, 7, 31, 12, 30, 45))
# Saving an object again doesn't create a new object -- it just saves
# the old one.
current_id = a8.id
a8.save()
self.assertEqual(a8.id, current_id)
a8.headline = 'Updated article 8'
a8.save()
self.assertEqual(a8.id, current_id)
# Check that != and == operators behave as expecte on instances
self.assertTrue(a7 != a8)
self.assertFalse(a7 == a8)
self.assertEqual(a8, Article.objects.get(id__exact=a8.id))
self.assertTrue(Article.objects.get(id__exact=a8.id) != Article.objects.get(id__exact=a7.id))
self.assertFalse(Article.objects.get(id__exact=a8.id) == Article.objects.get(id__exact=a7.id))
# You can use 'in' to test for membership...
self.assertTrue(a8 in Article.objects.all())
# ... but there will often be more efficient ways if that is all you need:
self.assertTrue(Article.objects.filter(id=a8.id).exists())
# datetimes() returns a list of available dates of the given scope for
# the given field.
self.assertQuerysetEqual(
Article.objects.datetimes('pub_date', 'year'),
["datetime.datetime(2005, 1, 1, 0, 0)"])
self.assertQuerysetEqual(
Article.objects.datetimes('pub_date', 'month'),
["datetime.datetime(2005, 7, 1, 0, 0)"])
self.assertQuerysetEqual(
Article.objects.datetimes('pub_date', 'day'),
["datetime.datetime(2005, 7, 28, 0, 0)",
"datetime.datetime(2005, 7, 29, 0, 0)",
"datetime.datetime(2005, 7, 30, 0, 0)",
"datetime.datetime(2005, 7, 31, 0, 0)"])
self.assertQuerysetEqual(
Article.objects.datetimes('pub_date', 'day', order='ASC'),
["datetime.datetime(2005, 7, 28, 0, 0)",
"datetime.datetime(2005, 7, 29, 0, 0)",
"datetime.datetime(2005, 7, 30, 0, 0)",
"datetime.datetime(2005, 7, 31, 0, 0)"])
self.assertQuerysetEqual(
Article.objects.datetimes('pub_date', 'day', order='DESC'),
["datetime.datetime(2005, 7, 31, 0, 0)",
"datetime.datetime(2005, 7, 30, 0, 0)",
"datetime.datetime(2005, 7, 29, 0, 0)",
"datetime.datetime(2005, 7, 28, 0, 0)"])
# datetimes() requires valid arguments.
self.assertRaises(
TypeError,
Article.objects.dates,
)
six.assertRaisesRegex(self,
FieldDoesNotExist,
"Article has no field named 'invalid_field'",
Article.objects.dates,
"invalid_field",
"year",
)
six.assertRaisesRegex(self,
AssertionError,
"'kind' must be one of 'year', 'month' or 'day'.",
Article.objects.dates,
"pub_date",
"bad_kind",
)
six.assertRaisesRegex(self,
AssertionError,
"'order' must be either 'ASC' or 'DESC'.",
Article.objects.dates,
"pub_date",
"year",
order="bad order",
)
# Use iterator() with datetimes() to return a generator that lazily
# requests each result one at a time, to save memory.
dates = []
for article in Article.objects.datetimes('pub_date', 'day', order='DESC').iterator():
dates.append(article)
self.assertEqual(dates, [
datetime(2005, 7, 31, 0, 0),
datetime(2005, 7, 30, 0, 0),
datetime(2005, 7, 29, 0, 0),
datetime(2005, 7, 28, 0, 0)])
# You can combine queries with & and |.
s1 = Article.objects.filter(id__exact=a.id)
s2 = Article.objects.filter(id__exact=a2.id)
self.assertQuerysetEqual(s1 | s2,
["<Article: Area man programs in Python>",
"<Article: Second article>"])
self.assertQuerysetEqual(s1 & s2, [])
# You can get the number of objects like this:
self.assertEqual(len(Article.objects.filter(id__exact=a.id)), 1)
# You can get items using index and slice notation.
self.assertEqual(Article.objects.all()[0], a)
self.assertQuerysetEqual(Article.objects.all()[1:3],
["<Article: Second article>", "<Article: Third article>"])
s3 = Article.objects.filter(id__exact=a3.id)
self.assertQuerysetEqual((s1 | s2 | s3)[::2],
["<Article: Area man programs in Python>",
"<Article: Third article>"])
# Slicing works with longs (Python 2 only -- Python 3 doesn't have longs).
if not six.PY3:
self.assertEqual(Article.objects.all()[long(0)], a)
self.assertQuerysetEqual(Article.objects.all()[long(1):long(3)],
["<Article: Second article>", "<Article: Third article>"])
self.assertQuerysetEqual((s1 | s2 | s3)[::long(2)],
["<Article: Area man programs in Python>",
"<Article: Third article>"])
# And can be mixed with ints.
self.assertQuerysetEqual(Article.objects.all()[1:long(3)],
["<Article: Second article>", "<Article: Third article>"])
# Slices (without step) are lazy:
self.assertQuerysetEqual(Article.objects.all()[0:5].filter(),
["<Article: Area man programs in Python>",
"<Article: Second article>",
"<Article: Third article>",
"<Article: Article 6>",
"<Article: Default headline>"])
# Slicing again works:
self.assertQuerysetEqual(Article.objects.all()[0:5][0:2],
["<Article: Area man programs in Python>",
"<Article: Second article>"])
self.assertQuerysetEqual(Article.objects.all()[0:5][:2],
["<Article: Area man programs in Python>",
"<Article: Second article>"])
self.assertQuerysetEqual(Article.objects.all()[0:5][4:],
["<Article: Default headline>"])
self.assertQuerysetEqual(Article.objects.all()[0:5][5:], [])
# Some more tests!
self.assertQuerysetEqual(Article.objects.all()[2:][0:2],
["<Article: Third article>", "<Article: Article 6>"])
self.assertQuerysetEqual(Article.objects.all()[2:][:2],
["<Article: Third article>", "<Article: Article 6>"])
self.assertQuerysetEqual(Article.objects.all()[2:][2:3],
["<Article: Default headline>"])
# Using an offset without a limit is also possible.
self.assertQuerysetEqual(Article.objects.all()[5:],
["<Article: Fourth article>",
"<Article: Article 7>",
"<Article: Updated article 8>"])
# Also, once you have sliced you can't filter, re-order or combine
six.assertRaisesRegex(self,
AssertionError,
"Cannot filter a query once a slice has been taken.",
Article.objects.all()[0:5].filter,
id=a.id,
)
six.assertRaisesRegex(self,
AssertionError,
"Cannot reorder a query once a slice has been taken.",
Article.objects.all()[0:5].order_by,
'id',
)
try:
Article.objects.all()[0:1] & Article.objects.all()[4:5]
self.fail('Should raise an AssertionError')
except AssertionError as e:
self.assertEqual(str(e), "Cannot combine queries once a slice has been taken.")
except Exception as e:
self.fail('Should raise an AssertionError, not %s' % e)
# Negative slices are not supported, due to database constraints.
# (hint: inverting your ordering might do what you need).
try:
Article.objects.all()[-1]
self.fail('Should raise an AssertionError')
except AssertionError as e:
self.assertEqual(str(e), "Negative indexing is not supported.")
except Exception as e:
self.fail('Should raise an AssertionError, not %s' % e)
error = None
try:
Article.objects.all()[0:-5]
except Exception as e:
error = e
self.assertIsInstance(error, AssertionError)
self.assertEqual(str(error), "Negative indexing is not supported.")
# An Article instance doesn't have access to the "objects" attribute.
# That's only available on the class.
six.assertRaisesRegex(self,
AttributeError,
"Manager isn't accessible via Article instances",
getattr,
a7,
"objects",
)
# Bulk delete test: How many objects before and after the delete?
self.assertQuerysetEqual(Article.objects.all(),
["<Article: Area man programs in Python>",
"<Article: Second article>",
"<Article: Third article>",
"<Article: Article 6>",
"<Article: Default headline>",
"<Article: Fourth article>",
"<Article: Article 7>",
"<Article: Updated article 8>"])
Article.objects.filter(id__lte=a4.id).delete()
self.assertQuerysetEqual(Article.objects.all(),
["<Article: Article 6>",
"<Article: Default headline>",
"<Article: Article 7>",
"<Article: Updated article 8>"])
@skipUnlessDBFeature('supports_microsecond_precision')
def test_microsecond_precision(self):
# In PostgreSQL, microsecond-level precision is available.
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))
@skipIfDBFeature('supports_microsecond_precision')
def test_microsecond_precision_not_supported(self):
# In MySQL, microsecond-level precision isn't available. You'll lose
# microsecond-level precision once the data is saved.
a9 = Article(
headline='Article 9',
pub_date=datetime(2005, 7, 31, 12, 30, 45, 180),
)
a9.save()
self.assertEqual(Article.objects.get(id__exact=a9.id).pub_date,
datetime(2005, 7, 31, 12, 30, 45))
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.
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),
)
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 = set([a10, a11, a12])
self.assertTrue(Article.objects.get(headline='Article 11') in s)
def test_field_ordering(self):
"""
Field instances have a `__lt__` comparison function to define an
ordering based on their creation. Prior to #17851 this ordering
comparison relied on the now unsupported `__cmp__` and was assuming
compared objects were both Field instances raising `AttributeError`
when it should have returned `NotImplemented`.
"""
f1 = Field()
f2 = Field(auto_created=True)
f3 = Field()
self.assertTrue(f2 < f1)
self.assertTrue(f3 > f1)
self.assertFalse(f1 == None)
self.assertFalse(f2 in (None, 1, ''))
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().
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),
)
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.
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),
)
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_ugettext_lazy(self):
"""
Test that ugettext_lazy objects work when saving model instances
through various methods. Refs #10498.
"""
notlazy = 'test'
lazy = ugettext_lazy(notlazy)
reporter = 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 objecs
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):
# Can't be instantiated
with self.assertRaises(TypeError):
EmptyQuerySet()
self.assertIsInstance(Article.objects.none(), 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.assertIsInstance(qs, ValuesListQuerySet)
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)
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()
connections[DEFAULT_DB_ALIAS].commit_unless_managed()
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')