manage.py test and uninstalled apps

[Claude Paroz]

Hello,

I have a Django project with different apps and settings. Let's say settings A have A in INSTALLED_APPS but not B, and settings B have B in INSTALLED_APPS but not A. Note also that I cannot have both apps installed, for some reason.
In that configuration and from Django 1.9, ./manage.py test will always fail with the message :
    RuntimeError: Model class <myapp.models.MyModel> doesn't declare an explicit app_label and either isn't in an application in INSTALLED_APPS or else was imported before its application was loaded.

Do we admit that for such type of projects, you always have to specify your app labels starting from Django 1.9?
Or did I miss some hidden trick to avoid that?

Claude

[Aymeric Augustin]

Hello Claude,

Generally speaking, you cannot safely use a model that isn't defined in an application that is in INSTALLED_APPS. Django raises a warning when you import such a model.

This restriction prevents situations where relations between models aren't set up correctly. There’s a string of such bugs in Trac. I discussed this in my DjangoCon Europe 2014 talk.

Best regards,

-- 

Aymeric.

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[Claude Paroz]

Hello Aymeric,

To be clear, I don't contest in any way that design choice. I understand and approve it.
I'm just pointing to this unwanted side-effect, wondering if anyone has ideas how to circumvent it, as I think it's a legitimate use case.
I'm also aware that we have not much control over test discovery and importing process.

The workaround for me will probably to write a custom test management command to define test labels dynamically based on current settings.

Claude

[Aymeric Augustin]

2015-11-19 8:27 GMT+01:00 Claude Paroz <cla...@2xlibre.net>:

To be clear, I don't contest in any way that design choice. I understand and approve it.
I'm just pointing to this unwanted side-effect, wondering if anyone has ideas how to circumvent it, as I think it's a legitimate use case.

Ah, I misunderstood "to specify your app labels" as "to specify your app labels on your models' Meta classes" while you meant "to specify your app labels on the command line when running tests".

Since the test discovery will try to import everything and problems appear when importing models, I'm afraid there isn't a good solution here.

 

--

Aymeric.