'Check that querysets will use the default database by default'

def test_db_selection(self):

    self.assertEqual(Book.objects.db, DEFAULT_DB_ALIAS)
    self.assertEqual(Book.objects.all().db, DEFAULT_DB_ALIAS)
    self.assertEqual(Book.objects.using('other').db, 'other')
    self.assertEqual(Book.objects.db_manager('other').db, 'other')
    self.assertEqual(Book.objects.db_manager('other').all().db, 'other')
