TransactionManagementError：当试图测试

Question

我有一个model和manager为

class PlaylistManager(models.Manager): 
    def add_playlist(self, name): 
     playlist = self.model(name) 
     playlist.save() 
     return playlist 

class Playlist(models.Model): 
    name = models.CharField(max_length=30) 
    date_created = models.DateTimeField(auto_now_add=True) 
    date_modified = models.DateTimeField(auto_now=True) 
    deleted = models.BooleanField(default=False) 
    objects = PlaylistManager() # is a customer manager 

    class Meta: 
     db_table = 'playlists' 

然后我写了test，使这个代码是不是事务管理下确保这个工程

from django.test import TestCase 
from models import Playlist 

""" 
The idea is that each call to create playlist will make a new playlist 

""" 

PLAYLIST = 'playlist' 
class PlaylistTest(TestCase): 
    def insert_playlist(playlist=PLAYLIST): 
     Playlist.objects.add_playlist(playlist) 

    def test_add_one_video_to_playlist(self): 
     self.insert_playlist() 
     self.assertEqual(Playlist.objects.count(), 0, msg='playlist count is not 1, it is ' + str(Playlist.objects.count())) 

当我从命令行运行此测试我看到以下错误

$ python manage.py test playlists --settings=myApp.settings.dev 
Creating test database for alias 'default'... 
EE 
====================================================================== 
ERROR: test_add_one_video_to_playlist (myApp.apps.playlists.tests.PlaylistTest) 
---------------------------------------------------------------------- 
Traceback (most recent call last): 
    File "/Users/me/code/p/myApp/myApp/apps/playlists/tests.py", line 15, in test_add_one_video_to_playlist 
    self.insert_playlist() 
    File "/Users/me/code/p/myApp/myApp/apps/playlists/tests.py", line 12, in insert_playlist 
    Playlist.objects.add_playlist(playlist) 
    File "/Users/me/code/p/myApp/myApp/apps/playlists/models.py", line 8, in add_playlist 
    playlist.save() 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/base.py", line 463, in save 
    self.save_base(using=using, force_insert=force_insert, force_update=force_update) 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/base.py", line 524, in save_base 
    manager.using(using).filter(pk=pk_val).exists())): 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/query.py", line 621, in filter 
    return self._filter_or_exclude(False, *args, **kwargs) 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/query.py", line 639, in _filter_or_exclude 
    clone.query.add_q(Q(*args, **kwargs)) 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1250, in add_q 
    can_reuse=used_aliases, force_having=force_having) 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/models/sql/query.py", line 1099, in add_filter 
    value = value() 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/test/testcases.py", line 512, in __call__ 
    result.addError(self, sys.exc_info()) 
AttributeError: 'NoneType' object has no attribute 'addError' 

====================================================================== 
ERROR: test_add_one_video_to_playlist (myApp.apps.playlists.tests.PlaylistTest) 
---------------------------------------------------------------------- 
Traceback (most recent call last): 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/test/testcases.py", line 508, in __call__ 
    self._post_teardown() 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/test/testcases.py", line 522, in _post_teardown 
    self._fixture_teardown() 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/test/testcases.py", line 847, in _fixture_teardown 
    transaction.leave_transaction_management(using=db) 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/transaction.py", line 52, in leave_transaction_management 
    connection.leave_transaction_management() 
    File "/Users/me/code/p/virtualenv/myApp/lib/python2.7/site-packages/django/db/backends/__init__.py", line 115, in leave_transaction_management 
    raise TransactionManagementError("This code isn't under transaction " 
TransactionManagementError: This code isn't under transaction management 

---------------------------------------------------------------------- 
Ran 1 test in 0.102s 

FAILED (errors=2) 
Destroying test database for alias 'default'... 

我不知道这里发生了什么事。我所知道的，我有一个Transaction Management Middleware为

MIDDLEWARE_CLASSES = (
    'django.middleware.common.CommonMiddleware', 
    'django.contrib.sessions.middleware.SessionMiddleware', 
    'django.middleware.csrf.CsrfViewMiddleware', 
    'django.contrib.auth.middleware.AuthenticationMiddleware', 
    'django.contrib.messages.middleware.MessageMiddleware', 
    # -- db transaction management -- # 
    'django.middleware.cache.UpdateCacheMiddleware', 
    'django.contrib.sessions.middleware.SessionMiddleware', 
    'django.middleware.common.CommonMiddleware', 
    'django.middleware.transaction.TransactionMiddleware', 
    'django.middleware.cache.FetchFromCacheMiddleware', 
    # Uncomment the next line for simple clickjacking protection: 
    # 'django.middleware.clickjacking.XFrameOptionsMiddleware', 
) 

我计划我views.py功能使用，因为

@transaction.commit_on_success 
def addPlaylist(name): 
    """ 
    adds playlist 
    """ 
    pass 

，但目前没有任何的意见，函数调用

请帮助我在这里发生了什么

谢谢

UPDATE

我使用Django 1.4

09:28:21 $ python 
Python 2.7.1 (r271:86832, Jul 31 2011, 19:30:53) 
[GCC 4.2.1 (Based on Apple Inc. build 5658) (LLVM build 2335.15.00)] on darwin 
Type "help", "copyright", "credits" or "license" for more information. 
>>> import django 
>>> django.VERSION 
(1, 4, 0, 'final', 0) 
>>> 

Answer 1

更改我的PlaylistManager到以下后，事情开始工作

class PlaylistManager(models.Manager): 
    def add_playlist(self, name): 
     playlist = Playlist(name=name) # this line changed 
     playlist.save() 
     return playlist