TransactionManagementError "You can't execute queries until the end of the 'atomic' block" while using signals, but only during Unit Testing

Question

I am getting TransactionManagementError when trying to save a Django User model instance and in its post_save signal, I'm saving some models that have the user as the foreign key.

The context and error is pretty similar to this question django TransactionManagementError when using signals

However, in this case, the error occurs only while unit testing.

It works well in manual testing, but unit tests fails.

Is there anything that I'm missing?

Here are the code snippets:

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)

Traceback:

======================================================================
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.

----------------------------------------------------------------------

From the docs: "A TestCase, on the other hand, does not truncate tables after a test. Instead, it encloses the test code in a database transaction that is rolled back at the end of the test. Both explicit commits like transaction.commit() and implicit ones that may be caused by transaction.atomic() are replaced with a nop operation. This guarantees that the rollback at the end of the test restores the database to its initial state." — Gaurav Toshniwal, Feb 13 '14 at 13:06
I found my problem. There was an IntegrityError exception like this "try: ... except IntegrityError: ..." what I had to do is to use the transaction.atomic inside the try-block: "try: with transaction.atomic(): ... except IntegrityError: ..." now everything works fine. — caio, Feb 13 '14 at 17:09
https://docs.djangoproject.com/en/dev/topics/db/transactions/ and then search for "Wrapping atomic in a try/except block allows for natural handling of integrity errors:" — CamHart, Apr 11 '14 at 22:57

score 333 · Accepted Answer · edited Feb 21 '23 at 19:40

333

I ran into this same problem myself. This is caused by a quirk in how transactions are handled in the newer versions of Django coupled with a unittest that intentionally triggers an exception.

I had a unittest that checked to make sure a unique column constraint was enforced by purposefully triggering an IntegrityError exception:

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()

In Django 1.4, this works fine. However, in Django 1.5/1.6, each test is wrapped in a transaction, so if an exception occurs, it breaks the transaction until you explicitly roll it back. Therefore, any further ORM operations in that transaction, such as my do_more_model_stuff(), will fail with that django.db.transaction.TransactionManagementError exception.

Like caio mentioned in the comments, the solution is to capture your exception with transaction.atomic like:

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

That will prevent the purposefully-thrown exception from breaking the entire unittest's transaction.

edited Feb 21 '23 at 19:40

phoenix

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answered Apr 27 '14 at 18:01

Cerin

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Also consider just declaring your test class as a TransactionTestCase rather than just TestCase. – mkoistinen Jan 19 '15 at 16:56
This reply helps resolve my problem, too! Thanks for that! However, I am also curious *HOW* you solved this problem when you encountered that? Did you investigate yourself? Or you sent an email to the user list? Or what..? – yaobin Jun 01 '15 at 14:08
1

Oh, I found the related document from another [question](http://stackoverflow.com/questions/20130507/django-transactionmanagementerror-when-using-signals). The document is [here](https://docs.djangoproject.com/en/1.8/topics/db/transactions/). – yaobin Jun 01 '15 at 15:39
4

For me, I _already_ had a `transaction.atomic()` block, but I got this error and I had no idea why. I took this answer's advice and put a _nested_ atomic block inside of my atomic block around the trouble-area. After that, it gave a detailed error of the integrity error I hit, allowing me to fix my code and do what I was trying to do. – AlanSE Dec 22 '16 at 19:08
5

@mkoistinen `TestCase` is inheriting from `TransactionTestCase` so no need to change that. If you don't operate on DB in test use `SimpleTestCase`. – bns Nov 16 '17 at 11:18
7

@bns you're missing the point of the comment. Yes `TestCase` inherits from `TransactionTestCase` but its behavior is quite different: it wraps each test method in a transaction. `TransactionTestCase`, on the other hand, is perhaps misleadingly named: it truncates tables to reset the db -- the naming seems to reflect that you can test transactions within a test, not that the test is wrapped as a transaction! – C S Sep 20 '18 at 17:40
This does not work if the exception catching is happening inside of the function being called such as `do_more_model_stuff` in this case. For example, I want to run a function that operates on the model and handles errors. None of these suggestions seem to avoid the `TransactionManagementError` described – user5359531 Sep 04 '20 at 16:29
3

Be careful, if you need to use `setUpTestData` you can't use it with `TransactionTestCase` it needs to be used with `TestCase`. While testing my integrity error for unique group, I had to wrap the `save` call inside the `with atomic()` block – Vincent Sep 27 '21 at 14:06

kdazzle · Answer 2 · 2023-06-05T20:36:58.257

63

Since @mkoistinen never made their comment an answer, I'll post the suggestion so people won't have to dig through comments.

consider just declaring your test class as a TransactionTestCase rather than just TestCase.

From the Django docs: A TransactionTestCase may call commit and rollback and observe the effects of these calls on the database.

edited Jun 05 '23 at 20:36

answered Jan 14 '16 at 23:45

kdazzle

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+1 for this, but, as the docs say, "Django’s TestCase class is a more commonly used subclass of TransactionTestCase". To answer the original question, shouldn't we use SimpleTestCase instead of TestCase? SimpleTestCase doesn't have the atomic database features. – daigorocub May 02 '16 at 15:56
@daigorocub When inheriting from `SimpleTestCase`, `allow_database_queries = True` must be added inside the test class, so it doesn't spit an `AssertionError("Database queries aren't allowed in SimpleTestCase...",)`. – CristiFati Jan 25 '17 at 16:20
2

This is the answer that works best for me as I was trying to test for integrityerror will be raised and then subsequently I needed to run more database save queries – Kim Stacks Oct 09 '18 at 01:40
1

Important to keep in mind that `TransactionTestCase` can be significantly slower than a traditional `TestCase`. – Dougyfresh Nov 05 '21 at 23:55

score 23 · Answer 3 · answered Feb 06 '19 at 23:07

If using pytest-django you can pass transaction=True to the django_db decorator to avoid this error.

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

Django itself has the TransactionTestCase which allows you to test transactions and will flush the database between tests to isolate them. The downside of this is that these tests are much slower to set up due to the required flushing of the database. pytest-django also supports this style of tests, which you can select using an argument to the django_db mark:

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

I had an issue with this solution, I had initial data in my DB (added by migrations). This solution flush the database, so other tests dependent on this initial data started to fail. — abumalick, May 24 '19 at 22:46

score 12 · Answer 4 · edited Apr 03 '20 at 14:23

12

Here is another way to do it, based on the answer to this question:

with transaction.atomic():
    self.assertRaises(IntegrityError, models.Question.objects.create, **{'domain':self.domain, 'slug':'barks'})

edited Apr 03 '20 at 14:23

B. Go

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answered Apr 03 '20 at 13:35

Mahdi Hamzeh

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score 2 · Answer 5 · answered Nov 11 '20 at 19:24

In my case it was caused but not calling super().tearDownClass()

class TnsFileViewSetTestCase(APITestCase):
    @classmethod
    def tearDownClass(self):
        super().tearDownClass()    # without this line we will get TransactionManagementError
        for tnsfile in TnsFile.objects.all():
            tnsfile.file.delete()

score 1 · Answer 6 · answered Jul 28 '17 at 03:11

I have the same issue, but with transaction.atomic() and TransactionTestCase didn't work for me.

python manage.py test -r instead of python manage.py test is ok for me, maybe the order of execution is crucial

then i find a doc about Order in which tests are executed, It mentions which test will run first.

So, i use TestCase for database interaction, unittest.TestCase for other simple test, it works now!

score 1 · Answer 7 · answered Oct 29 '18 at 13:11

For me, the proposed fixes did not work. In my tests, I open some subprocesses with Popen to analyze/lint migrations (e.g. one test checks if there are no model changes).

For me, subclassing from SimpleTestCase instead of TestCase did do the trick.

Note that SimpleTestCase doesn't allow to use the database.

While this does not answer the original question, I hope this helps some people anyway.

score 1 · Answer 8 · answered Apr 29 '20 at 09:37

def test_wrong_user_country_db_constraint(self):
        """
        Check whether or not DB constraint doesnt allow to save wrong country code in DB.
        """
        self.test_user_data['user_country'] = 'XX'
        expected_constraint_name = "country_code_within_list_of_countries_check"

        with transaction.atomic():
            with self.assertRaisesRegex(IntegrityError, expected_constraint_name) as cm:
                get_user_model().objects.create_user(**self.test_user_data)

        self.assertFalse(
            get_user_model().objects.filter(email=self.test_user_data['email']).exists()
        )

with transaction.atomic() seems do the job correct

score 0 · Answer 9 · answered Nov 02 '16 at 11:42

I was getting this error on running unit tests in my create_test_data function using django 1.9.7. It worked in earlier versions of django.

It looked like this:

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

My solution was to use update_or_create instead:

cls.localauth,_ = Organisation.objects.update_or_create(organisation_type=cls.orgtypeLA, name='LA for test', email_general='test@test.com', 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='test@test.com', 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='test@test.com', address='test', postcode='test', telephone='test', defaults={'active': True})

`get_or_create()` works as well, it seems it's the .save() it doesnt like inside a transaction.atomic() decorated function (mine failed with just 1 call in there). — belteshazzar, Nov 18 '16 at 09:51

Shil Nevado · Answer 10 · 2018-10-30T12:14:26.387

The answer of @kdazzle is correct. I didnt try it because people said that 'Django’s TestCase class is a more commonly used subclass of TransactionTestCase' so I thought it was the same use one or another. But the blog of Jahongir Rahmonov explained it better:

the TestCase class wraps the tests within two nested atomic() blocks: one for the whole class and one for each test. This is where TransactionTestCase should be used. It does not wrap the tests with atomic() block and thus you can test your special methods that require a transaction without any problem.

EDIT: It didn't work, I thought yes, but NO.

In 4 years they could fixed this.......................................

score -2 · Answer 11 · edited Feb 01 '18 at 23:02

-2

I had the same issue.

In My Case I was doing this

author.tasks.add(tasks)

so converting it to

author.tasks.add(*tasks)

Removed that error.

edited Feb 01 '18 at 23:02

YakovL

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answered Feb 21 '16 at 13:23

Diaa Mohamed Kasem

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TransactionManagementError "You can't execute queries until the end of the 'atomic' block" while using signals, but only during Unit Testing

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