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]

        )