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 model that inherits from it just for testing purposes; are there any elegant/simple ways to define that model just for testing?

I have seen some "hacks" that make this possible, but never seen an "official" way in the django documentation or in other similar places.

Answer 1

Just stumbled across this feature myself: You can just inherit from your abstract model in tests.py and test that as usual. When you run 'manage.py tests', Django not only creates a test database, but also validates & syncs your test models.

Tested it with current Django trunk (version 1.2).

Answer 2

Updated for Django >=2.0

So I was running into a few problems using m4rk4l's answer: one being the 'RuntimeWarning: Model 'myapp.__test__mymodel' was already registered' issue brought up in one of the comments, another being tests failing because the table already exists.

I've added a few checks to help solve these issues and now it works flawlessly. I hope this helps people

from django.db import connection from django.db.models.base import ModelBase from django.db.utils import OperationalError from django.test import TestCase   class AbstractModelMixinTestCase(TestCase):     """     Base class for tests of model mixins/abstract models.     To use, subclass and specify the mixin class variable.     A model using the mixin will be made available in self.model     """  @classmethod def setUpTestData(cls):     # Create a dummy model which extends the mixin. A RuntimeWarning will     # occur if the model is registered twice     if not hasattr(cls, 'model'):         cls.model = ModelBase(             '__TestModel__' +             cls.mixin.__name__, (cls.mixin,),             {'__module__': cls.mixin.__module__}         )      # Create the schema for our test model. If the table already exists,     # will pass     try:         with connection.schema_editor() as schema_editor:             schema_editor.create_model(cls.model)         super(AbstractModelMixinTestCase, cls).setUpClass()     except OperationalError:         pass  @classmethod def tearDownClass(self):     # Delete the schema for the test model. If no table, will pass     try:         with connection.schema_editor() as schema_editor:             schema_editor.delete_model(self.model)         super(AbstractModelMixinTestCase, self).tearDownClass()     except OperationalError:         pass 

To use, implement the same way as above (now with the correcting indentation):

class MyModelTestCase(AbstractModelMixinTestCase):     """Test abstract model."""     mixin = MyModel      def setUp(self):         self.model.objects.create(pk=1)      def test_a_thing(self):         mod = self.model.objects.get(pk=1)