django/tests/modeltests/get_object_or_404/tests.py

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from __future__ import absolute_import
from django.http import Http404
from django.shortcuts import get_object_or_404, get_list_or_404
from django.test import TestCase
from .models import Author, Article
class GetObjectOr404Tests(TestCase):
def test_get_object_or_404(self):
a1 = Author.objects.create(name="Brave Sir Robin")
a2 = Author.objects.create(name="Patsy")
# No Articles yet, so we should get a Http404 error.
self.assertRaises(Http404, get_object_or_404, Article, title="Foo")
article = Article.objects.create(title="Run away!")
article.authors = [a1, a2]
# get_object_or_404 can be passed a Model to query.
self.assertEqual(
get_object_or_404(Article, title__contains="Run"),
article
)
# We can also use the Article manager through an Author object.
self.assertEqual(
get_object_or_404(a1.article_set, title__contains="Run"),
article
)
# No articles containing "Camelot". This should raise a Http404 error.
self.assertRaises(Http404,
get_object_or_404, a1.article_set, title__contains="Camelot"
)
# Custom managers can be used too.
self.assertEqual(
get_object_or_404(Article.by_a_sir, title="Run away!"),
article
)
# QuerySets can be used too.
self.assertEqual(
get_object_or_404(Article.objects.all(), title__contains="Run"),
article
)
# Just as when using a get() lookup, you will get an error if more than
# one object is returned.
self.assertRaises(Author.MultipleObjectsReturned,
get_object_or_404, Author.objects.all()
)
# Using an EmptyQuerySet raises a Http404 error.
self.assertRaises(Http404,
get_object_or_404, Article.objects.none(), title__contains="Run"
)
# get_list_or_404 can be used to get lists of objects
self.assertEqual(
get_list_or_404(a1.article_set, title__icontains="Run"),
[article]
)
# Http404 is returned if the list is empty.
self.assertRaises(Http404,
get_list_or_404, a1.article_set, title__icontains="Shrubbery"
)
# Custom managers can be used too.
self.assertEqual(
get_list_or_404(Article.by_a_sir, title__icontains="Run"),
[article]
)
# QuerySets can be used too.
self.assertEqual(
get_list_or_404(Article.objects.all(), title__icontains="Run"),
[article]
)
def test_bad_class(self):
# Given an argument klass that is not a Model, Manager, or Queryset
# raises a helpful ValueError message
self.assertRaisesMessage(ValueError,
"Object is of type 'str', but must be a Django Model, Manager, "
"or QuerySet",
get_object_or_404, "Article", title__icontains="Run"
)
class CustomClass(object):
pass
self.assertRaisesMessage(ValueError,
"Object is of type 'CustomClass', but must be a Django Model, "
"Manager, or QuerySet",
get_object_or_404, CustomClass, title__icontains="Run"
)
# Works for lists too
self.assertRaisesMessage(ValueError,
"Object is of type 'list', but must be a Django Model, Manager, "
"or QuerySet",
get_list_or_404, [Article], title__icontains="Run"
)