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from __future__ import unicode_literals
from django.test import TestCase
from .models import Author, Publisher
class GetOrCreateTests(TestCase):
def test_related(self):
p = Publisher.objects.create(name="Acme Publishing")
# Create a book through the publisher.
book, created = p.books.get_or_create(name="The Book of Ed & Fred")
self.assertTrue(created)
# The publisher should have one book.
self.assertEqual(p.books.count(), 1)
# Try get_or_create again, this time nothing should be created.
book, created = p.books.get_or_create(name="The Book of Ed & Fred")
self.assertFalse(created)
# And the publisher should still have one book.
self.assertEqual(p.books.count(), 1)
# Add an author to the book.
ed, created = book.authors.get_or_create(name="Ed")
self.assertTrue(created)
# The book should have one author.
self.assertEqual(book.authors.count(), 1)
# Try get_or_create again, this time nothing should be created.
ed, created = book.authors.get_or_create(name="Ed")
self.assertFalse(created)
# And the book should still have one author.
self.assertEqual(book.authors.count(), 1)
# Add a second author to the book.
fred, created = book.authors.get_or_create(name="Fred")
self.assertTrue(created)
# The book should have two authors now.
self.assertEqual(book.authors.count(), 2)
# Create an Author not tied to any books.
Author.objects.create(name="Ted")
# There should be three Authors in total. The book object should have two.
self.assertEqual(Author.objects.count(), 3)
self.assertEqual(book.authors.count(), 2)
# Try creating a book through an author.
_, created = ed.books.get_or_create(name="Ed's Recipes", publisher=p)
self.assertTrue(created)
# Now Ed has two Books, Fred just one.
self.assertEqual(ed.books.count(), 2)
self.assertEqual(fred.books.count(), 1)
# Use the publisher's primary key value instead of a model instance.
_, created = ed.books.get_or_create(name='The Great Book of Ed', publisher_id=p.id)
self.assertTrue(created)
# Try get_or_create again, this time nothing should be created.
_, created = ed.books.get_or_create(name='The Great Book of Ed', publisher_id=p.id)
self.assertFalse(created)
# The publisher should have three books.
self.assertEqual(p.books.count(), 3)
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