[1.6.x] Fixed #21472 -- Fixed inline formsets display when parent pk is 0

        self.save_as_new = save_as_new

        if queryset is None:

            queryset = self.model._default_manager

        if self.instance.pk:

        if self.instance.pk is not None:

            qs = queryset.filter(**{self.fk.name: self.instance})

        else:

            qs = queryset.none()

  for the non-breaking space was returned verbatim (#21415).

* Fixed :djadmin:`loaddata` error when fixture file name contained any dots

  non related to file extensions (#21457).

* Fixed display of inline instances in formsets when parent has 0 for primary

  key (#21472).

from __future__ import absolute_import, unicode_literals

from django.forms.models import inlineformset_factory

from django.test import TestCase

from django.test import TestCase, skipUnlessDBFeature

from django.utils import six

from .models import Poet, Poem, School, Parent, Child

        inlineformset_factory(

            Parent, Child, exclude=('school',), fk_name='mother'

        )

    @skipUnlessDBFeature('allows_primary_key_0')

    def test_zero_primary_key(self):

        # Regression test for #21472

        poet = Poet.objects.create(id=0, name='test')

        poem = poet.poem_set.create(name='test poem')

        PoemFormSet = inlineformset_factory(Poet, Poem, fields="__all__", extra=0)

        formset = PoemFormSet(None, instance=poet)

        self.assertEqual(len(formset.forms), 1)