Django: Best way to unit-test an abstract model

Question

I need to write some unit tests for an abstract base model, that provides some basic functionality that should be used by other apps. It it would be necessary to define a mo

Answer 1

I tried solutions here but ran into issues like

RuntimeWarning: Model 'myapp.__test__mymodel' was already registered

Looking up how to test abstract models with pytest wasn't any successful either. I eventually came up with this solution that works perfectly for me:

import tempfile

import pytest
from django.db import connection, models
from model_mommy import mommy

from ..models import AbstractModel


@pytest.fixture(scope='module')
def django_db_setup(django_db_setup, django_db_blocker):
    with django_db_blocker.unblock():

        class DummyModel(AbstractModel):
            pass

        class DummyImages(models.Model):
            dummy = models.ForeignKey(
                DummyModel, on_delete=models.CASCADE, related_name='images'
            )
            image = models.ImageField()

        with connection.schema_editor() as schema_editor:
            schema_editor.create_model(DummyModel)
            schema_editor.create_model(DummyImages)


@pytest.fixture
def temporary_image_file():
    image = tempfile.NamedTemporaryFile()
    image.name = 'test.jpg'
    return image.name


@pytest.mark.django_db
def test_fileuploader_model_file_name(temporary_image_file):
    image = mommy.make('core.dummyimages', image=temporary_image_file)
    assert image.file_name == 'test.jpg'


@pytest.mark.django_db
def test_fileuploader_model_file_mime_type(temporary_image_file):
    image = mommy.make('core.dummyimages', image=temporary_image_file)
    assert image.file_mime_type == 'image/jpeg'

As you can see, I define a Class that inherits from the Abstractmodel, and add it as a fixture. Now with the flexibility of model mommy, I can create a DummyImages object, and it will automatically create a DummyModel for me too!

Alternatively, I could've made the example simple by not including foreign keys, but it demonstrates the flexibility of pytest and model mommy in combination quite well.