#28400: TransactionTestCase will truncate data created from data migration
-------------------------------------+-------------------------------------
Reporter: Jared Mackey | Owner: nobody
Type: Bug | Status: new
Component: Testing framework | Version: 1.11
Severity: Normal | Resolution:
Keywords: tests,data- | Triage Stage:
migrations | Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
-------------------------------------+-------------------------------------
Description changed by Jared Mackey:
Old description:
> Data migrations that create data in the database do not persist after
> running tests that inherit from `TransactionTestCase`. The first test
> that runs on the database works as expected but subsequent tests do not.
>
> Here is an example migration:
>
> {{{
> def add_group_permissions(apps, schema_editor):
> for app_config in apps.get_app_configs():
> app_config.models_module = True
> create_permissions(app_config, verbosity=0)
> app_config.models_module = None
>
> Group = apps.get_model('auth', 'Group')
> Permission = apps.get_model('auth', 'Permission')
>
> group, _ = Group.objects.get_or_create(name='demo_group')
> group.permissions.clear()
> permission = Permission.objects.get(codename='existing_permission')
> group.permissions.add(permission)
>
> class Migration(migrations.Migration):
>
> dependencies = [ ]
>
> operations = [
> migrations.RunPython(add_group_permissions,
> reverse_code=migrations.RunPython.noop),
> migrations.RunPython(lambda apps, schema_editor:
> ContentType.objects.clear_cache()), # hack to get the ContentType cache
> to clear
> ]
> }}}
>
> Here is a test case that will prove that the second test to run will fail
> with `django.contrib.auth.models.DoesNotExist: Group matching query does
> not exist.`
>
> {{{
> class TestGroupsExist(TransactionTestCase):
> """ One of these tests will fail. Which one depends on which one the
> test runner runs first. The second one to run will fail. """
> def test_group_exists_1(self):
> self.assertIsNotNone(Group.objects.get_by_natural_key('demo_group'))
>
> def test_group_exists_2(self):
> self.assertIsNotNone(Group.objects.get_by_natural_key('demo_group'))
> }}}
>
> The following log is found after the first test is ran.
>
> `TRUNCATE ... "auth_group_permissions", "auth_group", ...;; args=None`
>
> A possible solution to this is to re-run data only migrations after
> truncating the tables.
New description:
Data migrations that create data in the database do not persist after
running tests that inherit from `TransactionTestCase`. The first test that
runs on the database works as expected but subsequent tests do not. I am
filling as a bug as I would expect that data created before tests are ran
would persist a transaction rollback during the test cases. A possible
solution to this is to re-run data only migrations after truncating the
tables.
Here is an example migration:
{{{
def add_group_permissions(apps, schema_editor):
for app_config in apps.get_app_configs():
app_config.models_module = True
create_permissions(app_config, verbosity=0)
app_config.models_module = None
Group = apps.get_model('auth', 'Group')
Permission = apps.get_model('auth', 'Permission')
group, _ = Group.objects.get_or_create(name='demo_group')
group.permissions.clear()
permission = Permission.objects.get(codename='existing_permission')
group.permissions.add(permission)
class Migration(migrations.Migration):
dependencies = [ ]
operations = [
migrations.RunPython(add_group_permissions,
reverse_code=migrations.RunPython.noop),
migrations.RunPython(lambda apps, schema_editor:
ContentType.objects.clear_cache()), # hack to get the ContentType cache
to clear
]
}}}
Here is a test case that will prove that the second test to run will fail
with `django.contrib.auth.models.DoesNotExist: Group matching query does
not exist.`
{{{
class TestGroupsExist(TransactionTestCase):
""" One of these tests will fail. Which one depends on which one the
test runner runs first. The second one to run will fail. """
def test_group_exists_1(self):
self.assertIsNotNone(Group.objects.get_by_natural_key('demo_group'))
def test_group_exists_2(self):
self.assertIsNotNone(Group.objects.get_by_natural_key('demo_group'))
}}}
The following log is found after the first test is ran.
`TRUNCATE ... "auth_group_permissions", "auth_group", ...;; args=None`
--
--
Ticket URL: <https://code.djangoproject.com/ticket/28400#comment:1>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
--
You received this message because you are subscribed to the Google Groups
"Django updates" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to django-updates+unsubscr...@googlegroups.com.
To post to this group, send email to django-updates@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/django-updates/068.a86c064f5e7ff20c6cea5c9905ceae04%40djangoproject.com.
For more options, visit https://groups.google.com/d/optout.
