[Django] #28320: Parallel testing: Please implement a signal or call checks after test DB creation but before cloning it.
Django
creation but before cloning it.
------------------------------------------------+------------------------
Reporter: László Károlyi | Owner: nobody
Type: Cleanup/optimization | Status: new
Component: Testing framework | Version: 1.11
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Needs documentation: 0 | Needs tests: 0
Patch needs improvement: 0 | Easy pickings: 0
UI/UX: 0 |
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Hi,
I tried to reach someone on IRC, but actually it's better to document my
issue here, maybe there will be a solution to it eventually.
I'm trying to use the new and shiny parallel testing functionality of
Django 1.11, and I've run into problems with it.
So I have functionality implemented on `check` and the `post_migrate`
signal, where I conditionally insert stuff into the DB that can't be
inserted by fixtures, and also conditionally modify DB fields that can't
be done from the ORM. (the latter is basically changing collation on a
column)
It seems that the post_migrate signal is run randomly before and after the
test creation, and checks are only run *after* the DB is cloned, so I
don't have a sufficient point where I can have my logic run.
Monkey-patching has shown that the best solution would be to run
`call_command('check')`
[https://github.com/django/django/blob/master/django/test/utils.py#L178
here], so basically after `create_test_db` but before `clone_test_db`.
I can quickly add that, but I'm not sure how it could be tested, and what
implications it would have, so I'm asking you guys, if you think it's
doable and feasible. Because of this right now, I can't use parallel
testing.
--
Ticket URL: <https://code.djangoproject.com/ticket/28320>
Django <https://code.djangoproject.com/>
The Web framework for perfectionists with deadlines.
Django
creation but before cloning it.
Reporter: László Károlyi | Owner: nobody
Cleanup/optimization |
Component: Testing framework | Version: 1.11
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by László Károlyi):
Update:
It seems I managed to consistently insert the needed data into the DB
before it gets cloned by subclassing the testrunner and running checks
before `setup_databases()` runs. But that brought another problem I
discovered, and which maybe could be fixed.
So the first part I'm doing at startup is, I update my own permission
models, which subclass the original django `Permission` model. Formerly, I
had a function that would give a `ContentType` model of
`django.contrib.auth`:
{{{#!python
def _get_perm_contenttype(app_label: str, model_name: str):
"""
Return a `ContentType`.
"""
from django.contrib.contenttypes.models import ContentType
return ContentType.objects.get_for_model(
apps.get_model(app_label=app_label, model_name=model_name))
}}}
Because `ContentType.objects.get_for_model()` caches, and because the
nature of the parallel testing, that cached result sometimes brought
models with wrong `ID`s, and I got constraint violations because no such
IDs existed in my DB.
I fixed my code by not using `get_for_model()`, and using `get()` instead.
I'm just leaving this information here for your consideration.
--
Ticket URL: <https://code.djangoproject.com/ticket/28320#comment:1>
Django
creation but before cloning it.
Reporter: László Károlyi | Owner: nobody
Cleanup/optimization |
Component: Testing framework | Version: 1.11
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Comment (by Tim Graham):
#15610 and #16281 might be related to the contenttypes issue. Can we close
this ticket then? If there's some issue with contenttypes, it's likely
more clear to open a separate ticket about that.
--
Ticket URL: <https://code.djangoproject.com/ticket/28320#comment:2>
Django
creation but before cloning it.
Reporter: László Károlyi | Owner: nobody
Cleanup/optimization |
Component: Testing framework | Version: 1.11
Keywords: | Triage Stage:
| Unreviewed
Has patch: 0 | Needs documentation: 0
Needs tests: 0 | Patch needs improvement: 0
Easy pickings: 0 | UI/UX: 0
Changes (by László Károlyi):
* status: new => closed
* resolution: => duplicate
Comment:
Replying to [comment:2 Tim Graham]:
> Can we close this ticket then?
I think so, yes. Thx, closing.
--
Ticket URL: <https://code.djangoproject.com/ticket/28320#comment:3>