How to test a model relationship in Django

Question

In Django what is the best way to test that an object can correctly save a relationship?

This is what I have, which works, but I am not 100% sure it is the right way to go.

class ModelCase(TestCase):

    def setUp(self):
        self.company = mommy.make(Company)
        noz.assert_true(isinstance(self.company, Company))
        self.campaign = mommy.make(Campaign)


    def test_assign_campaign_to_company(self):
        """
        Test if a campaign can be assigned to a company
        """
        self.campaign.company = self.company
        self.campaign.save()
        noz.assert_true(self.campaign.company.name)

Does this really test the actually condition or should I be doing something else?

Answer 1

This assertion doesn't look up the database. It asserts on the objects in the memory.

To query the database best use:

(Campaign.objects
         .filter(
             pk=self.campaign.pk, 
             company=self.company)
         .exists())