发布到 Django 表单时，是否发布了所有字段？

Question

I'm trying to write a test for a form to simulate the situation in which I'd like to update just one field. Here is the test:

from django.test import TestCase
from django.forms.models import model_to_dict

class FamilyDemographicsUpdateTest(TestCase):
    def test_update_phone_types_with_fields_from_family_factory(self):
        # Create a family for which the employee uses an iPhone
        family = FamilyFactory(employee_phone_type=Family.IPHONE)
        url = reverse('dashboard:family', kwargs={'pk': family.id, 'tab': 'family-demographics'})

        data = model_to_dict(instance=family, fields=FamilyDemographicsForm.base_fields)

        form = FamilyDemographicsForm(data=data)

after which I drop into the debugger with import ipdb; ipdb.set_trace() import ipdb; ipdb.set_trace() . It is here that I notice that the form has errors :

ipdb> form.errors
{'employee_email': ['This email is already taken.']}

This can be traced back to the Family model on which the form is based. The form is a ModelForm :

class FamilyDemographicsForm(forms.ModelForm):
    class Meta:
        model = Family

The view is based on Django's generic UpdateView :

class FamilyUpdate(SuccessMessageMixin, DashboardAccessMixin, UpdateView):
    template_name = 'families/edit.html'
    model = Family
    success_message = "Family was updated successfully."

    def get_form_class(self, **kwargs):
        tab = self.kwargs['tab']
        if tab == 'family-demographics':
            return FamilyDemographicsForm

and the corresponding Family object has a clean() method which is triggering this error (in class Family(models.Model) ):

def clean(self):
    if self.employee_email:
        db_user = User.objects.filter(username=self.employee_email).first()
        if db_user and db_user.family and db_user.family != self:
            raise ValidationError({'employee_email': 'This email is already taken.'})
    if self.partner_email:
        db_user = User.objects.filter(username=self.partner_email).first()
        if db_user and db_user.family and db_user.family != self:
            raise ValidationError({'partner_email': 'This email is already taken.'})

However, if I actually use the form in the browser and submit, it seems to work just fine. In short, when you submit a form in the browser, is that not equivalent to post ing data which is - for the fields that you haven't changed - are the same as they initially were? Why is this error getting triggered in this test and not in the browser?

Answer 1

This doesn't have anything to do with posting data at all. The issue is that your view is an update, which passes the existing instance to the form so that Django knows how to update it. Your test doesn't do that.

(Your test isn't really testing your code; you should really be calling the view, either with the request factory or the test client, v and passing your data in there.)