Django Test what form a formset uses

Question

If I have a form like:

class MyForm(modelForm):
    # Form stuff

And a formset like:

MyFormSet = modelformset_factory(
    MyModel,
    form=MyForm,
    max_num=6,
    validate_max=True,
)

Is there a way to test that form=MyForm?

def test_formset(self):

    formset = MyFormSet()

    self.assertEqual(formset.max_num, 6)
    self.assertTrue(formset.validate_max)
    # Tried this but it didn't work
    self.assertIsInstance(formset.form, MyForm)

GwynBleidD · Accepted Answer · 2019-01-26T13:38:23.077

1

In this case, formset.form will be a subclass of MyForm class, not instance of it, so assertIsInstance will not work. You can check it simply using:

def test_formset(self):

    formset = MyFormSet()
    self.assertTrue(issubclass(formset.form, MyForm))

for formset_factory and when you don't want to allow any subclass of MyForm to be provided, this will also work (as formset_factory won't modify your form class):

def test_formset(self):

    formset = MyFormSet()
    self.assertEquals(formset.form, MyForm)

edited Jan 26 '19 at 13:38

answered Jan 26 '19 at 12:54

GwynBleidD

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The first one actually did not work, but the second one did. – Carl Brubaker Jan 26 '19 at 13:00
Yeah, for `modelformset_factory` django is creating subclass from provided form. I've adjusted my answer. – GwynBleidD Jan 26 '19 at 13:36

Django Test what form a formset uses

1 Answers1