TransactionManagementError“在使用信号时,您只能在'atomic'块的末尾才能执行查询”,但仅在单元测试期间

问题描述 投票:180回答:9

尝试保存Django User模型实例时,我收到TransactionManagementError,并且在其post_save信号中,我保存了一些将用户作为外键的模型。

上下文和错误与此问题非常相似django TransactionManagementError when using signals

但是,在这种情况下,发生错误仅在单元测试时

在手动测试中效果很好,但是单元测试失败。

我有什么想念的吗?

以下是代码段:

views.py

@csrf_exempt
def mobileRegister(request):
    if request.method == 'GET':
        response = {"error": "GET request not accepted!!"}
        return HttpResponse(json.dumps(response), content_type="application/json",status=500)
    elif request.method == 'POST':
        postdata = json.loads(request.body)
        try:
            # Get POST data which is to be used to save the user
            username = postdata.get('phone')
            password = postdata.get('password')
            email = postdata.get('email',"")
            first_name = postdata.get('first_name',"")
            last_name = postdata.get('last_name',"")
            user = User(username=username, email=email,
                        first_name=first_name, last_name=last_name)
            user._company = postdata.get('company',None)
            user._country_code = postdata.get('country_code',"+91")
            user.is_verified=True
            user._gcm_reg_id = postdata.get('reg_id',None)
            user._gcm_device_id = postdata.get('device_id',None)
            # Set Password for the user
            user.set_password(password)
            # Save the user
            user.save()

signal.py

def create_user_profile(sender, instance, created, **kwargs):
    if created:
        company = None
        companycontact = None
        try:   # Try to make userprofile with company and country code provided
            user = User.objects.get(id=instance.id)
            rand_pass = random.randint(1000, 9999)
            company = Company.objects.get_or_create(name=instance._company,user=user)
            companycontact = CompanyContact.objects.get_or_create(contact_type="Owner",company=company,contact_number=instance.username)
            profile = UserProfile.objects.get_or_create(user=instance,phone=instance.username,verification_code=rand_pass,company=company,country_code=instance._country_code)
            gcmDevice = GCMDevice.objects.create(registration_id=instance._gcm_reg_id,device_id=instance._gcm_reg_id,user=instance)
        except Exception, e:
            pass

tests.py

class AuthTestCase(TestCase):
    fixtures = ['nextgencatalogs/fixtures.json']
    def setUp(self):
        self.user_data={
            "phone":"0000000000",
            "password":"123",
            "first_name":"Gaurav",
            "last_name":"Toshniwal"
            }

    def test_registration_api_get(self):
        response = self.client.get("/mobileRegister/")
        self.assertEqual(response.status_code,500)

    def test_registration_api_post(self):
        response = self.client.post(path="/mobileRegister/",
                                    data=json.dumps(self.user_data),
                                    content_type="application/json")
        self.assertEqual(response.status_code,201)
        self.user_data['username']=self.user_data['phone']
        user = User.objects.get(username=self.user_data['username'])
        # Check if the company was created
        company = Company.objects.get(user__username=self.user_data['phone'])
        self.assertIsInstance(company,Company)
        # Check if the owner's contact is the same as the user's phone number
        company_contact = CompanyContact.objects.get(company=company,contact_type="owner")
        self.assertEqual(user.username,company_contact[0].contact_number)

追踪:

======================================================================
ERROR: test_registration_api_post (nextgencatalogs.apps.catalogsapp.tests.AuthTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/nextgencatalogs/apps/catalogsapp/tests.py", line 29, in test_registration_api_post
    user = User.objects.get(username=self.user_data['username'])
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/manager.py", line 151, in get
    return self.get_queryset().get(*args, **kwargs)
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/query.py", line 301, in get
    num = len(clone)
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/query.py", line 77, in __len__
    self._fetch_all()
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/query.py", line 854, in _fetch_all
    self._result_cache = list(self.iterator())
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/query.py", line 220, in iterator
    for row in compiler.results_iter():
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 710, in results_iter
    for rows in self.execute_sql(MULTI):
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 781, in execute_sql
    cursor.execute(sql, params)
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/backends/util.py", line 47, in execute
    self.db.validate_no_broken_transaction()
  File "/Users/gauravtoshniwal1989/Developer/Web/Server/ngc/ngcvenv/lib/python2.7/site-packages/django/db/backends/__init__.py", line 365, in validate_no_broken_transaction
    "An error occurred in the current transaction. You can't "
TransactionManagementError: An error occurred in the current transaction. You can't execute queries until the end of the 'atomic' block.

----------------------------------------------------------------------
python django unit-testing django-signals
9个回答
225
投票

我本人也遇到了同样的问题。这是由于在新版本的Django中如何处理事务的古怪之处,加上故意触发异常的单元测试。

我进行了单元测试,通过有意触发IntegrityError异常来确保实施了唯一的列约束:

def test_constraint(self):
    try:
        # Duplicates should be prevented.
        models.Question.objects.create(domain=self.domain, slug='barks')
        self.fail('Duplicate question allowed.')
    except IntegrityError:
        pass

    do_more_model_stuff()

在Django 1.4中,此方法工作正常。但是,在Django 1.5 / 1.6中,每个测试都包装在一个事务中,因此,如果发生异常,它将破坏该事务,直到您显式回滚它为止。因此,该事务中的任何其他ORM操作(例如我的do_more_model_stuff())都将失败,并带有django.db.transaction.TransactionManagementError异常。

就像评论中提到的caio一样,解决方案是使用transaction.atomic捕获您的异常,例如:

from django.db import transaction
def test_constraint(self):
    try:
        # Duplicates should be prevented.
        with transaction.atomic():
            models.Question.objects.create(domain=self.domain, slug='barks')
        self.fail('Duplicate question allowed.')
    except IntegrityError:
        pass

这将防止故意抛出的异常破坏整个单元测试的事务。


47
投票

由于@mkoistinen从未提出his comment这样的答案,因此我将发布他的建议,这样人们就不必再挖掘评论了。

只需考虑将您的测试类声明为TransactionTestCase,而不只是TestCase。

docs:TransactionTestCase可以调用提交和回滚,并观察这些调用对数据库的影响。


7
投票

如果使用pytest-django,则可以将transaction=True传递给django_db装饰器,以避免出现此错误。

请参见https://pytest-django.readthedocs.io/en/latest/database.html#testing-transactions

Django本身具有TransactionTestCase,可让您测试事务,并将在两次测试之间刷新数据库以隔离他们。缺点是,由于需要刷新数据库,因此这些测试的建立速度要慢得多。 pytest-django也支持这种测试风格,您可以使用django_db标记的参数进行选择:

@pytest.mark.django_db(transaction=True)
def test_spam():
    pass  # test relying on transactions

1
投票

对我来说,建议的修补程序不起作用。在我的测试中,我使用Popen打开了一些子流程来分析/皮棉迁移(例如,一项测试检查是否没有模型更改)。

对我来说,从SimpleTestCase而不是TestCase继承确实可以解决问题。

请注意,SimpleTestCase不允许使用数据库。

虽然这不能回答原始问题,但我希望这对某些人有帮助。


0
投票

我在使用Django 1.9.7在create_test_data函数中运行单元测试时遇到此错误。它在Django的早期版本中有效。

看起来像这样:

cls.localauth,_ = Organisation.objects.get_or_create(organisation_type=cls.orgtypeLA, name='LA for test', email_general='[email protected]', address='test', postcode='test', telephone='test')
cls.chamber,_ = Organisation.objects.get_or_create(organisation_type=cls.orgtypeC, name='chamber for test', email_general='[email protected]', address='test', postcode='test', telephone='test')
cls.lawfirm,_ = Organisation.objects.get_or_create(organisation_type=cls.orgtypeL, name='lawfirm for test', email_general='[email protected]', address='test', postcode='test', telephone='test')

cls.chamber.active = True
cls.chamber.save()

cls.localauth.active = True
cls.localauth.save()    <---- error here

cls.lawfirm.active = True
cls.lawfirm.save()

我的解决方案是改用update_or_create:

cls.localauth,_ = Organisation.objects.update_or_create(organisation_type=cls.orgtypeLA, name='LA for test', email_general='[email protected]', address='test', postcode='test', telephone='test', defaults={'active': True})
cls.chamber,_ = Organisation.objects.update_or_create(organisation_type=cls.orgtypeC, name='chamber for test', email_general='[email protected]', address='test', postcode='test', telephone='test', defaults={'active': True})
cls.lawfirm,_ = Organisation.objects.update_or_create(organisation_type=cls.orgtypeL, name='lawfirm for test', email_general='[email protected]', address='test', postcode='test', telephone='test', defaults={'active': True})

0
投票

我有相同的问题,但with transaction.atomic()TransactionTestCase对我不起作用。

python manage.py test -r而不是python manage.py test对我来说没问题,也许执行的顺序很关键

然后我找到了有关Order in which tests are executed的文档,其中提到哪个测试将首先运行。

所以,我使用TestCase进行数据库交互,unittest.TestCase进行其他简单测试,现在可以使用!


0
投票

@ kdazzle的答案是正确的。我没有尝试过,因为人们说“ Django的TestCase类是TransactionTestCase的一个更常用的子类”,所以我认为这是一种或另一种相同的用法。但是blog of Jahongir Rahmonov解释得更好:

TestCase类将测试包装在两个嵌套的atomic()块中:全班一次,每项测试一次。这是哪里应该使用TransactionTestCase。它不会用atomic()块,因此您可以测试需要的特殊方法交易没有任何问题。

编辑:它没有用,我以为是,但不是。

他们可以在4年内解决此问题.......................................


0
投票

当我尝试创建具有用户名的用户时,发生单元测试我有此问题(django.db.transaction.TransactionManagementError: An error occurred in the current transaction. You can't execute queries until the end of the 'atomic' block.):

User.objects.create_user(username)

如果用户名已经存在,我将通过跳过用户创建来解决它。

if not User.objects.filter(username=username):
    User.objects.create_user(username)

-4
投票

我有同样的问题。

就我而言,我正在这样做

author.tasks.add(tasks)

因此将其转换为

author.tasks.add(*tasks)

已消除该错误。

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