CODEWITHSUNDEEP
djangodjango-testing
Jasper
Jasper

Reputation: 2231

Django: assert 'Many-to-many' relation exists in test

I am writing tests for my project, but I've run into a problem when trying to verify the existence of a 'ManyToMany' relationship.

The test concerns the following two models, that are linked together with a ManyToMany

Models:

class Project(models.Model):
    (...)
    linked_attributes = models.ManyToManyField(attributes, blank=True)


class Attributes(models.Model):
    (...)
    class linked_projects = models.ManyToManyField(Project, blank=True)

In my test I wanted to verify that the form created a new many to many relationship. I created the assert on the last line, based on some example code, but it doesn't seem to be working.

Test:

class ProjectTest(TestCase):
    (...)
    form_data = {'linked_attributes' : self.attribute}
    form = ProjectForm(data=form_data, project=self.project, instance=self.project)

   self.assertTrue(Project.attributes_set.filter(pk=self.Project.pk).exists())

Does anyone know what I am doing wrong?

Upvotes: 1

Views: 1159

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599450

Your model structure is wrong. You should only define the many-to-many on one side of the relationship; the other side is accessed via the reverse relationship.

Also, your assertion is wrong. You need to query the linked attributes via the project instance, not the Project class as a whole.

Finally, do you actually have some code before that assertion to validate and save the form? Otherwise nothing will have changed.

So:

self.assertTrue(form.is_valid())
saved_project = form.save()
self.assertTrue(saved_project.attributes_set.exists())

Upvotes: 2

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