django/tests/model_formsets/tests.py

import datetime
import re
from datetime import date
from decimal import Decimal

from django import forms
from django.core.exceptions import ImproperlyConfigured, ValidationError
from django.db import models
from django.forms.models import (
    BaseModelFormSet, _get_foreign_key, inlineformset_factory,
    modelformset_factory,
)
from django.http import QueryDict
from django.test import TestCase, skipUnlessDBFeature

from .models import (
    AlternateBook, Author, AuthorMeeting, BetterAuthor, Book, BookWithCustomPK,
    BookWithOptionalAltEditor, ClassyMexicanRestaurant, CustomPrimaryKey,
    Location, Membership, MexicanRestaurant, Owner, OwnerProfile, Person,
    Place, Player, Poem, Poet, Post, Price, Product, Repository, Restaurant,
    Revision, Team,
)


class DeletionTests(TestCase):
    def test_deletion(self):
        PoetFormSet = modelformset_factory(Poet, fields="__all__", can_delete=True)
        poet = Poet.objects.create(name='test')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '0',
            'form-0-id': str(poet.pk),
            'form-0-name': 'test',
            'form-0-DELETE': 'on',
        }
        formset = PoetFormSet(data, queryset=Poet.objects.all())
        formset.save(commit=False)
        self.assertEqual(Poet.objects.count(), 1)

        formset.save()
        self.assertTrue(formset.is_valid())
        self.assertEqual(Poet.objects.count(), 0)

    def test_add_form_deletion_when_invalid(self):
        """
        Make sure that an add form that is filled out, but marked for deletion
        doesn't cause validation errors.
        """
        PoetFormSet = modelformset_factory(Poet, fields="__all__", can_delete=True)
        poet = Poet.objects.create(name='test')
        # One existing untouched and two new unvalid forms
        data = {
            'form-TOTAL_FORMS': '3',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '0',
            'form-0-id': str(poet.id),
            'form-0-name': 'test',
            'form-1-id': '',
            'form-1-name': 'x' * 1000,  # Too long
            'form-2-id': str(poet.id),  # Violate unique constraint
            'form-2-name': 'test2',
        }
        formset = PoetFormSet(data, queryset=Poet.objects.all())
        # Make sure this form doesn't pass validation.
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(Poet.objects.count(), 1)

        # Then make sure that it *does* pass validation and delete the object,
        # even though the data in new forms aren't actually valid.
        data['form-0-DELETE'] = 'on'
        data['form-1-DELETE'] = 'on'
        data['form-2-DELETE'] = 'on'
        formset = PoetFormSet(data, queryset=Poet.objects.all())
        self.assertIs(formset.is_valid(), True)
        formset.save()
        self.assertEqual(Poet.objects.count(), 0)

    def test_change_form_deletion_when_invalid(self):
        """
        Make sure that a change form that is filled out, but marked for deletion
        doesn't cause validation errors.
        """
        PoetFormSet = modelformset_factory(Poet, fields="__all__", can_delete=True)
        poet = Poet.objects.create(name='test')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '0',
            'form-0-id': str(poet.id),
            'form-0-name': 'x' * 1000,
        }
        formset = PoetFormSet(data, queryset=Poet.objects.all())
        # Make sure this form doesn't pass validation.
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(Poet.objects.count(), 1)

        # Then make sure that it *does* pass validation and delete the object,
        # even though the data isn't actually valid.
        data['form-0-DELETE'] = 'on'
        formset = PoetFormSet(data, queryset=Poet.objects.all())
        self.assertIs(formset.is_valid(), True)
        formset.save()
        self.assertEqual(Poet.objects.count(), 0)

    def test_outdated_deletion(self):
        poet = Poet.objects.create(name='test')
        poem = Poem.objects.create(name='Brevity is the soul of wit', poet=poet)

        PoemFormSet = inlineformset_factory(Poet, Poem, fields="__all__", can_delete=True)

        # Simulate deletion of an object that doesn't exist in the database
        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '2',
            'form-0-id': str(poem.pk),
            'form-0-name': 'foo',
            'form-1-id': str(poem.pk + 1),  # doesn't exist
            'form-1-name': 'bar',
            'form-1-DELETE': 'on',
        }
        formset = PoemFormSet(data, instance=poet, prefix="form")

        # The formset is valid even though poem.pk + 1 doesn't exist,
        # because it's marked for deletion anyway
        self.assertTrue(formset.is_valid())

        formset.save()

        # Make sure the save went through correctly
        self.assertEqual(Poem.objects.get(pk=poem.pk).name, "foo")
        self.assertEqual(poet.poem_set.count(), 1)
        self.assertFalse(Poem.objects.filter(pk=poem.pk + 1).exists())


class ModelFormsetTest(TestCase):
    def test_modelformset_factory_without_fields(self):
        """ Regression for #19733 """
        message = (
            "Calling modelformset_factory without defining 'fields' or 'exclude' "
            "explicitly is prohibited."
        )
        with self.assertRaisesMessage(ImproperlyConfigured, message):
            modelformset_factory(Author)

    def test_simple_save(self):
        qs = Author.objects.all()
        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=3)

        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 3)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-name">Name:</label>'
            '<input id="id_form-0-name" type="text" name="form-0-name" maxlength="100">'
            '<input type="hidden" name="form-0-id" id="id_form-0-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_form-1-name">Name:</label>'
            '<input id="id_form-1-name" type="text" name="form-1-name" maxlength="100">'
            '<input type="hidden" name="form-1-id" id="id_form-1-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_form-2-name">Name:</label>'
            ' <input id="id_form-2-name" type="text" name="form-2-name" maxlength="100">'
            '<input type="hidden" name="form-2-id" id="id_form-2-id"></p>'
        )

        data = {
            'form-TOTAL_FORMS': '3',  # the number of forms rendered
            'form-INITIAL_FORMS': '0',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-name': 'Charles Baudelaire',
            'form-1-name': 'Arthur Rimbaud',
            'form-2-name': '',
        }

        formset = AuthorFormSet(data=data, queryset=qs)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 2)
        author1, author2 = saved
        self.assertEqual(author1, Author.objects.get(name='Charles Baudelaire'))
        self.assertEqual(author2, Author.objects.get(name='Arthur Rimbaud'))

        authors = list(Author.objects.order_by('name'))
        self.assertEqual(authors, [author2, author1])

        # Gah! We forgot Paul Verlaine. Let's create a formset to edit the
        # existing authors with an extra form to add him. We *could* pass in a
        # queryset to restrict the Author objects we edit, but in this case
        # we'll use it to display them in alphabetical order by name.

        qs = Author.objects.order_by('name')
        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=1, can_delete=False)

        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 3)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-name">Name:</label>'
            '<input id="id_form-0-name" type="text" name="form-0-name" value="Arthur Rimbaud" maxlength="100">'
            '<input type="hidden" name="form-0-id" value="%d" id="id_form-0-id"></p>' % author2.id
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_form-1-name">Name:</label>'
            '<input id="id_form-1-name" type="text" name="form-1-name" value="Charles Baudelaire" maxlength="100">'
            '<input type="hidden" name="form-1-id" value="%d" id="id_form-1-id"></p>' % author1.id
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_form-2-name">Name:</label>'
            '<input id="id_form-2-name" type="text" name="form-2-name" maxlength="100">'
            '<input type="hidden" name="form-2-id" id="id_form-2-id"></p>'
        )

        data = {
            'form-TOTAL_FORMS': '3',  # the number of forms rendered
            'form-INITIAL_FORMS': '2',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-id': str(author2.id),
            'form-0-name': 'Arthur Rimbaud',
            'form-1-id': str(author1.id),
            'form-1-name': 'Charles Baudelaire',
            'form-2-name': 'Paul Verlaine',
        }

        formset = AuthorFormSet(data=data, queryset=qs)
        self.assertTrue(formset.is_valid())

        # Only changed or new objects are returned from formset.save()
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        author3 = saved[0]
        self.assertEqual(author3, Author.objects.get(name='Paul Verlaine'))

        authors = list(Author.objects.order_by('name'))
        self.assertEqual(authors, [author2, author1, author3])

        # This probably shouldn't happen, but it will. If an add form was
        # marked for deletion, make sure we don't save that form.

        qs = Author.objects.order_by('name')
        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=1, can_delete=True)

        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 4)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-name">Name:</label>'
            '<input id="id_form-0-name" type="text" name="form-0-name" '
            'value="Arthur Rimbaud" maxlength="100"></p>'
            '<p><label for="id_form-0-DELETE">Delete:</label>'
            '<input type="checkbox" name="form-0-DELETE" id="id_form-0-DELETE">'
            '<input type="hidden" name="form-0-id" value="%d" id="id_form-0-id"></p>' % author2.id
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_form-1-name">Name:</label>'
            '<input id="id_form-1-name" type="text" name="form-1-name" '
            'value="Charles Baudelaire" maxlength="100"></p>'
            '<p><label for="id_form-1-DELETE">Delete:</label>'
            '<input type="checkbox" name="form-1-DELETE" id="id_form-1-DELETE">'
            '<input type="hidden" name="form-1-id" value="%d" id="id_form-1-id"></p>' % author1.id
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_form-2-name">Name:</label>'
            '<input id="id_form-2-name" type="text" name="form-2-name" '
            'value="Paul Verlaine" maxlength="100"></p>'
            '<p><label for="id_form-2-DELETE">Delete:</label>'
            '<input type="checkbox" name="form-2-DELETE" id="id_form-2-DELETE">'
            '<input type="hidden" name="form-2-id" value="%d" id="id_form-2-id"></p>' % author3.id
        )
        self.assertHTMLEqual(
            formset.forms[3].as_p(),
            '<p><label for="id_form-3-name">Name:</label>'
            '<input id="id_form-3-name" type="text" name="form-3-name" maxlength="100"></p>'
            '<p><label for="id_form-3-DELETE">Delete:</label>'
            '<input type="checkbox" name="form-3-DELETE" id="id_form-3-DELETE">'
            '<input type="hidden" name="form-3-id" id="id_form-3-id"></p>'
        )

        data = {
            'form-TOTAL_FORMS': '4',  # the number of forms rendered
            'form-INITIAL_FORMS': '3',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-id': str(author2.id),
            'form-0-name': 'Arthur Rimbaud',
            'form-1-id': str(author1.id),
            'form-1-name': 'Charles Baudelaire',
            'form-2-id': str(author3.id),
            'form-2-name': 'Paul Verlaine',
            'form-3-name': 'Walt Whitman',
            'form-3-DELETE': 'on',
        }

        formset = AuthorFormSet(data=data, queryset=qs)
        self.assertTrue(formset.is_valid())

        # No objects were changed or saved so nothing will come back.

        self.assertEqual(formset.save(), [])

        authors = list(Author.objects.order_by('name'))
        self.assertEqual(authors, [author2, author1, author3])

        # Let's edit a record to ensure save only returns that one record.

        data = {
            'form-TOTAL_FORMS': '4',  # the number of forms rendered
            'form-INITIAL_FORMS': '3',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-id': str(author2.id),
            'form-0-name': 'Walt Whitman',
            'form-1-id': str(author1.id),
            'form-1-name': 'Charles Baudelaire',
            'form-2-id': str(author3.id),
            'form-2-name': 'Paul Verlaine',
            'form-3-name': '',
            'form-3-DELETE': '',
        }

        formset = AuthorFormSet(data=data, queryset=qs)
        self.assertTrue(formset.is_valid())

        # One record has changed.

        saved = formset.save()
        self.assertEqual(len(saved), 1)
        self.assertEqual(saved[0], Author.objects.get(name='Walt Whitman'))

    def test_commit_false(self):
        # Test the behavior of commit=False and save_m2m

        author1 = Author.objects.create(name='Charles Baudelaire')
        author2 = Author.objects.create(name='Paul Verlaine')
        author3 = Author.objects.create(name='Walt Whitman')

        meeting = AuthorMeeting.objects.create(created=date.today())
        meeting.authors.set(Author.objects.all())

        # create an Author instance to add to the meeting.

        author4 = Author.objects.create(name='John Steinbeck')

        AuthorMeetingFormSet = modelformset_factory(AuthorMeeting, fields="__all__", extra=1, can_delete=True)
        data = {
            'form-TOTAL_FORMS': '2',  # the number of forms rendered
            'form-INITIAL_FORMS': '1',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-id': str(meeting.id),
            'form-0-name': '2nd Tuesday of the Week Meeting',
            'form-0-authors': [author2.id, author1.id, author3.id, author4.id],
            'form-1-name': '',
            'form-1-authors': '',
            'form-1-DELETE': '',
        }
        formset = AuthorMeetingFormSet(data=data, queryset=AuthorMeeting.objects.all())
        self.assertTrue(formset.is_valid())

        instances = formset.save(commit=False)
        for instance in instances:
            instance.created = date.today()
            instance.save()
        formset.save_m2m()
        self.assertQuerysetEqual(instances[0].authors.all(), [
            '<Author: Charles Baudelaire>',
            '<Author: John Steinbeck>',
            '<Author: Paul Verlaine>',
            '<Author: Walt Whitman>',
        ])

    def test_max_num(self):
        # Test the behavior of max_num with model formsets. It should allow
        # all existing related objects/inlines for a given object to be
        # displayed, but not allow the creation of new inlines beyond max_num.

        Author.objects.create(name='Charles Baudelaire')
        Author.objects.create(name='Paul Verlaine')
        Author.objects.create(name='Walt Whitman')

        qs = Author.objects.order_by('name')

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=None, extra=3)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 6)
        self.assertEqual(len(formset.extra_forms), 3)

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=4, extra=3)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 4)
        self.assertEqual(len(formset.extra_forms), 1)

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=0, extra=3)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 3)
        self.assertEqual(len(formset.extra_forms), 0)

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=None)
        formset = AuthorFormSet(queryset=qs)
        self.assertQuerysetEqual(formset.get_queryset(), [
            '<Author: Charles Baudelaire>',
            '<Author: Paul Verlaine>',
            '<Author: Walt Whitman>',
        ])

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=0)
        formset = AuthorFormSet(queryset=qs)
        self.assertQuerysetEqual(formset.get_queryset(), [
            '<Author: Charles Baudelaire>',
            '<Author: Paul Verlaine>',
            '<Author: Walt Whitman>',
        ])

        AuthorFormSet = modelformset_factory(Author, fields="__all__", max_num=4)
        formset = AuthorFormSet(queryset=qs)
        self.assertQuerysetEqual(formset.get_queryset(), [
            '<Author: Charles Baudelaire>',
            '<Author: Paul Verlaine>',
            '<Author: Walt Whitman>',
        ])

    def test_min_num(self):
        # Test the behavior of min_num with model formsets. It should be
        # added to extra.
        qs = Author.objects.none()

        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=0)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 0)

        AuthorFormSet = modelformset_factory(Author, fields="__all__", min_num=1, extra=0)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 1)

        AuthorFormSet = modelformset_factory(Author, fields="__all__", min_num=1, extra=1)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 2)

    def test_min_num_with_existing(self):
        # Test the behavior of min_num with existing objects.
        Author.objects.create(name='Charles Baudelaire')
        qs = Author.objects.all()

        AuthorFormSet = modelformset_factory(Author, fields="__all__", extra=0, min_num=1)
        formset = AuthorFormSet(queryset=qs)
        self.assertEqual(len(formset.forms), 1)

    def test_custom_save_method(self):
        class PoetForm(forms.ModelForm):
            def save(self, commit=True):
                # change the name to "Vladimir Mayakovsky" just to be a jerk.
                author = super().save(commit=False)
                author.name = "Vladimir Mayakovsky"
                if commit:
                    author.save()
                return author

        PoetFormSet = modelformset_factory(Poet, fields="__all__", form=PoetForm)

        data = {
            'form-TOTAL_FORMS': '3',  # the number of forms rendered
            'form-INITIAL_FORMS': '0',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-name': 'Walt Whitman',
            'form-1-name': 'Charles Baudelaire',
            'form-2-name': '',
        }

        qs = Poet.objects.all()
        formset = PoetFormSet(data=data, queryset=qs)
        self.assertTrue(formset.is_valid())

        poets = formset.save()
        self.assertEqual(len(poets), 2)
        poet1, poet2 = poets
        self.assertEqual(poet1.name, 'Vladimir Mayakovsky')
        self.assertEqual(poet2.name, 'Vladimir Mayakovsky')

    def test_custom_form(self):
        """
        model_formset_factory() respects fields and exclude parameters of a
        custom form.
        """
        class PostForm1(forms.ModelForm):
            class Meta:
                model = Post
                fields = ('title', 'posted')

        class PostForm2(forms.ModelForm):
            class Meta:
                model = Post
                exclude = ('subtitle',)

        PostFormSet = modelformset_factory(Post, form=PostForm1)
        formset = PostFormSet()
        self.assertNotIn("subtitle", formset.forms[0].fields)

        PostFormSet = modelformset_factory(Post, form=PostForm2)
        formset = PostFormSet()
        self.assertNotIn("subtitle", formset.forms[0].fields)

    def test_custom_queryset_init(self):
        """
        A queryset can be overridden in the formset's __init__() method.
        """
        Author.objects.create(name='Charles Baudelaire')
        Author.objects.create(name='Paul Verlaine')

        class BaseAuthorFormSet(BaseModelFormSet):
            def __init__(self, *args, **kwargs):
                super().__init__(*args, **kwargs)
                self.queryset = Author.objects.filter(name__startswith='Charles')

        AuthorFormSet = modelformset_factory(Author, fields='__all__', formset=BaseAuthorFormSet)
        formset = AuthorFormSet()
        self.assertEqual(len(formset.get_queryset()), 1)

    def test_model_inheritance(self):
        BetterAuthorFormSet = modelformset_factory(BetterAuthor, fields="__all__")
        formset = BetterAuthorFormSet()
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-name">Name:</label>'
            '<input id="id_form-0-name" type="text" name="form-0-name" maxlength="100"></p>'
            '<p><label for="id_form-0-write_speed">Write speed:</label>'
            '<input type="number" name="form-0-write_speed" id="id_form-0-write_speed">'
            '<input type="hidden" name="form-0-author_ptr" id="id_form-0-author_ptr"></p>'
        )

        data = {
            'form-TOTAL_FORMS': '1',  # the number of forms rendered
            'form-INITIAL_FORMS': '0',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-author_ptr': '',
            'form-0-name': 'Ernest Hemingway',
            'form-0-write_speed': '10',
        }

        formset = BetterAuthorFormSet(data)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        author1, = saved
        self.assertEqual(author1, BetterAuthor.objects.get(name='Ernest Hemingway'))
        hemingway_id = BetterAuthor.objects.get(name="Ernest Hemingway").pk

        formset = BetterAuthorFormSet()
        self.assertEqual(len(formset.forms), 2)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-name">Name:</label>'
            '<input id="id_form-0-name" type="text" name="form-0-name" value="Ernest Hemingway" maxlength="100"></p>'
            '<p><label for="id_form-0-write_speed">Write speed:</label>'
            '<input type="number" name="form-0-write_speed" value="10" id="id_form-0-write_speed">'
            '<input type="hidden" name="form-0-author_ptr" value="%d" id="id_form-0-author_ptr"></p>' % hemingway_id
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_form-1-name">Name:</label>'
            '<input id="id_form-1-name" type="text" name="form-1-name" maxlength="100"></p>'
            '<p><label for="id_form-1-write_speed">Write speed:</label>'
            '<input type="number" name="form-1-write_speed" id="id_form-1-write_speed">'
            '<input type="hidden" name="form-1-author_ptr" id="id_form-1-author_ptr"></p>'
        )

        data = {
            'form-TOTAL_FORMS': '2',  # the number of forms rendered
            'form-INITIAL_FORMS': '1',  # the number of forms with initial data
            'form-MAX_NUM_FORMS': '',  # the max number of forms
            'form-0-author_ptr': hemingway_id,
            'form-0-name': 'Ernest Hemingway',
            'form-0-write_speed': '10',
            'form-1-author_ptr': '',
            'form-1-name': '',
            'form-1-write_speed': '',
        }

        formset = BetterAuthorFormSet(data)
        self.assertTrue(formset.is_valid())
        self.assertEqual(formset.save(), [])

    def test_inline_formsets(self):
        # We can also create a formset that is tied to a parent model. This is
        # how the admin system's edit inline functionality works.

        AuthorBooksFormSet = inlineformset_factory(Author, Book, can_delete=False, extra=3, fields="__all__")
        author = Author.objects.create(name='Charles Baudelaire')

        formset = AuthorBooksFormSet(instance=author)
        self.assertEqual(len(formset.forms), 3)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_book_set-0-title">Title:</label> <input id="id_book_set-0-title" type="text" '
            'name="book_set-0-title" maxlength="100"><input type="hidden" name="book_set-0-author" value="%d" '
            'id="id_book_set-0-author"><input type="hidden" name="book_set-0-id" id="id_book_set-0-id">'
            '</p>' % author.id
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_book_set-1-title">Title:</label>'
            '<input id="id_book_set-1-title" type="text" name="book_set-1-title" maxlength="100">'
            '<input type="hidden" name="book_set-1-author" value="%d" id="id_book_set-1-author">'
            '<input type="hidden" name="book_set-1-id" id="id_book_set-1-id"></p>' % author.id
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_book_set-2-title">Title:</label>'
            '<input id="id_book_set-2-title" type="text" name="book_set-2-title" maxlength="100">'
            '<input type="hidden" name="book_set-2-author" value="%d" id="id_book_set-2-author">'
            '<input type="hidden" name="book_set-2-id" id="id_book_set-2-id"></p>' % author.id
        )

        data = {
            'book_set-TOTAL_FORMS': '3',  # the number of forms rendered
            'book_set-INITIAL_FORMS': '0',  # the number of forms with initial data
            'book_set-MAX_NUM_FORMS': '',  # the max number of forms
            'book_set-0-title': 'Les Fleurs du Mal',
            'book_set-1-title': '',
            'book_set-2-title': '',
        }

        formset = AuthorBooksFormSet(data, instance=author)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 1)
        book1, = saved
        self.assertEqual(book1, Book.objects.get(title='Les Fleurs du Mal'))
        self.assertQuerysetEqual(author.book_set.all(), ['<Book: Les Fleurs du Mal>'])

        # Now that we've added a book to Charles Baudelaire, let's try adding
        # another one. This time though, an edit form will be available for
        # every existing book.

        AuthorBooksFormSet = inlineformset_factory(Author, Book, can_delete=False, extra=2, fields="__all__")
        author = Author.objects.get(name='Charles Baudelaire')

        formset = AuthorBooksFormSet(instance=author)
        self.assertEqual(len(formset.forms), 3)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_book_set-0-title">Title:</label>'
            '<input id="id_book_set-0-title" type="text" name="book_set-0-title" '
            'value="Les Fleurs du Mal" maxlength="100">'
            '<input type="hidden" name="book_set-0-author" value="%d" id="id_book_set-0-author">'
            '<input type="hidden" name="book_set-0-id" value="%d" id="id_book_set-0-id"></p>' % (
                author.id, book1.id,
            )
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_book_set-1-title">Title:</label>'
            '<input id="id_book_set-1-title" type="text" name="book_set-1-title" maxlength="100">'
            '<input type="hidden" name="book_set-1-author" value="%d" id="id_book_set-1-author">'
            '<input type="hidden" name="book_set-1-id" id="id_book_set-1-id"></p>' % author.id
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_book_set-2-title">Title:</label>'
            '<input id="id_book_set-2-title" type="text" name="book_set-2-title" maxlength="100">'
            '<input type="hidden" name="book_set-2-author" value="%d" id="id_book_set-2-author">'
            '<input type="hidden" name="book_set-2-id" id="id_book_set-2-id"></p>' % author.id
        )

        data = {
            'book_set-TOTAL_FORMS': '3',  # the number of forms rendered
            'book_set-INITIAL_FORMS': '1',  # the number of forms with initial data
            'book_set-MAX_NUM_FORMS': '',  # the max number of forms
            'book_set-0-id': str(book1.id),
            'book_set-0-title': 'Les Fleurs du Mal',
            'book_set-1-title': 'Les Paradis Artificiels',
            'book_set-2-title': '',
        }

        formset = AuthorBooksFormSet(data, instance=author)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 1)
        book2, = saved
        self.assertEqual(book2, Book.objects.get(title='Les Paradis Artificiels'))

        # As you can see, 'Les Paradis Artificiels' is now a book belonging to
        # Charles Baudelaire.
        self.assertQuerysetEqual(author.book_set.order_by('title'), [
            '<Book: Les Fleurs du Mal>',
            '<Book: Les Paradis Artificiels>',
        ])

    def test_inline_formsets_save_as_new(self):
        # The save_as_new parameter lets you re-associate the data to a new
        # instance.  This is used in the admin for save_as functionality.
        AuthorBooksFormSet = inlineformset_factory(Author, Book, can_delete=False, extra=2, fields="__all__")
        Author.objects.create(name='Charles Baudelaire')

        # An immutable QueryDict simulates request.POST.
        data = QueryDict(mutable=True)
        data.update({
            'book_set-TOTAL_FORMS': '3',  # the number of forms rendered
            'book_set-INITIAL_FORMS': '2',  # the number of forms with initial data
            'book_set-MAX_NUM_FORMS': '',  # the max number of forms
            'book_set-0-id': '1',
            'book_set-0-title': 'Les Fleurs du Mal',
            'book_set-1-id': '2',
            'book_set-1-title': 'Les Paradis Artificiels',
            'book_set-2-title': '',
        })
        data._mutable = False

        formset = AuthorBooksFormSet(data, instance=Author(), save_as_new=True)
        self.assertTrue(formset.is_valid())
        self.assertIs(data._mutable, False)

        new_author = Author.objects.create(name='Charles Baudelaire')
        formset = AuthorBooksFormSet(data, instance=new_author, save_as_new=True)
        saved = formset.save()
        self.assertEqual(len(saved), 2)
        book1, book2 = saved
        self.assertEqual(book1.title, 'Les Fleurs du Mal')
        self.assertEqual(book2.title, 'Les Paradis Artificiels')

        # Test using a custom prefix on an inline formset.

        formset = AuthorBooksFormSet(prefix="test")
        self.assertEqual(len(formset.forms), 2)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_test-0-title">Title:</label>'
            '<input id="id_test-0-title" type="text" name="test-0-title" maxlength="100">'
            '<input type="hidden" name="test-0-author" id="id_test-0-author">'
            '<input type="hidden" name="test-0-id" id="id_test-0-id"></p>'
        )

        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_test-1-title">Title:</label>'
            '<input id="id_test-1-title" type="text" name="test-1-title" maxlength="100">'
            '<input type="hidden" name="test-1-author" id="id_test-1-author">'
            '<input type="hidden" name="test-1-id" id="id_test-1-id"></p>'
        )

    def test_inline_formsets_with_custom_pk(self):
        # Test inline formsets where the inline-edited object has a custom
        # primary key that is not the fk to the parent object.
        self.maxDiff = 1024

        AuthorBooksFormSet2 = inlineformset_factory(
            Author, BookWithCustomPK, can_delete=False, extra=1, fields="__all__"
        )
        author = Author.objects.create(pk=1, name='Charles Baudelaire')

        formset = AuthorBooksFormSet2(instance=author)
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_bookwithcustompk_set-0-my_pk">My pk:</label>'
            '<input id="id_bookwithcustompk_set-0-my_pk" type="number" '
            'name="bookwithcustompk_set-0-my_pk" step="1"></p>'
            '<p><label for="id_bookwithcustompk_set-0-title">Title:</label>'
            '<input id="id_bookwithcustompk_set-0-title" type="text" '
            'name="bookwithcustompk_set-0-title" maxlength="100">'
            '<input type="hidden" name="bookwithcustompk_set-0-author" '
            'value="1" id="id_bookwithcustompk_set-0-author"></p>'
        )

        data = {
            'bookwithcustompk_set-TOTAL_FORMS': '1',  # the number of forms rendered
            'bookwithcustompk_set-INITIAL_FORMS': '0',  # the number of forms with initial data
            'bookwithcustompk_set-MAX_NUM_FORMS': '',  # the max number of forms
            'bookwithcustompk_set-0-my_pk': '77777',
            'bookwithcustompk_set-0-title': 'Les Fleurs du Mal',
        }

        formset = AuthorBooksFormSet2(data, instance=author)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 1)
        book1, = saved
        self.assertEqual(book1.pk, 77777)

        book1 = author.bookwithcustompk_set.get()
        self.assertEqual(book1.title, 'Les Fleurs du Mal')

    def test_inline_formsets_with_multi_table_inheritance(self):
        # Test inline formsets where the inline-edited object uses multi-table
        # inheritance, thus has a non AutoField yet auto-created primary key.

        AuthorBooksFormSet3 = inlineformset_factory(Author, AlternateBook, can_delete=False, extra=1, fields="__all__")
        author = Author.objects.create(pk=1, name='Charles Baudelaire')

        formset = AuthorBooksFormSet3(instance=author)
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_alternatebook_set-0-title">Title:</label>'
            '<input id="id_alternatebook_set-0-title" type="text" '
            'name="alternatebook_set-0-title" maxlength="100"></p>'
            '<p><label for="id_alternatebook_set-0-notes">Notes:</label>'
            '<input id="id_alternatebook_set-0-notes" type="text" '
            'name="alternatebook_set-0-notes" maxlength="100">'
            '<input type="hidden" name="alternatebook_set-0-author" value="1" '
            'id="id_alternatebook_set-0-author">'
            '<input type="hidden" name="alternatebook_set-0-book_ptr" '
            'id="id_alternatebook_set-0-book_ptr"></p>'
        )

        data = {
            'alternatebook_set-TOTAL_FORMS': '1',  # the number of forms rendered
            'alternatebook_set-INITIAL_FORMS': '0',  # the number of forms with initial data
            'alternatebook_set-MAX_NUM_FORMS': '',  # the max number of forms
            'alternatebook_set-0-title': 'Flowers of Evil',
            'alternatebook_set-0-notes': 'English translation of Les Fleurs du Mal'
        }

        formset = AuthorBooksFormSet3(data, instance=author)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 1)
        book1, = saved
        self.assertEqual(book1.title, 'Flowers of Evil')
        self.assertEqual(book1.notes, 'English translation of Les Fleurs du Mal')

    @skipUnlessDBFeature('supports_partially_nullable_unique_constraints')
    def test_inline_formsets_with_nullable_unique_together(self):
        # Test inline formsets where the inline-edited object has a
        # unique_together constraint with a nullable member

        AuthorBooksFormSet4 = inlineformset_factory(
            Author, BookWithOptionalAltEditor, can_delete=False, extra=2, fields="__all__"
        )
        author = Author.objects.create(pk=1, name='Charles Baudelaire')

        data = {
            'bookwithoptionalalteditor_set-TOTAL_FORMS': '2',  # the number of forms rendered
            'bookwithoptionalalteditor_set-INITIAL_FORMS': '0',  # the number of forms with initial data
            'bookwithoptionalalteditor_set-MAX_NUM_FORMS': '',  # the max number of forms
            'bookwithoptionalalteditor_set-0-author': '1',
            'bookwithoptionalalteditor_set-0-title': 'Les Fleurs du Mal',
            'bookwithoptionalalteditor_set-1-author': '1',
            'bookwithoptionalalteditor_set-1-title': 'Les Fleurs du Mal',
        }
        formset = AuthorBooksFormSet4(data, instance=author)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 2)
        book1, book2 = saved
        self.assertEqual(book1.author_id, 1)
        self.assertEqual(book1.title, 'Les Fleurs du Mal')
        self.assertEqual(book2.author_id, 1)
        self.assertEqual(book2.title, 'Les Fleurs du Mal')

    def test_inline_formsets_with_custom_save_method(self):
        AuthorBooksFormSet = inlineformset_factory(Author, Book, can_delete=False, extra=2, fields="__all__")
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        book1 = Book.objects.create(pk=1, author=author, title='Les Paradis Artificiels')
        book2 = Book.objects.create(pk=2, author=author, title='Les Fleurs du Mal')
        book3 = Book.objects.create(pk=3, author=author, title='Flowers of Evil')

        class PoemForm(forms.ModelForm):
            def save(self, commit=True):
                # change the name to "Brooklyn Bridge" just to be a jerk.
                poem = super().save(commit=False)
                poem.name = "Brooklyn Bridge"
                if commit:
                    poem.save()
                return poem

        PoemFormSet = inlineformset_factory(Poet, Poem, form=PoemForm, fields="__all__")

        data = {
            'poem_set-TOTAL_FORMS': '3',  # the number of forms rendered
            'poem_set-INITIAL_FORMS': '0',  # the number of forms with initial data
            'poem_set-MAX_NUM_FORMS': '',  # the max number of forms
            'poem_set-0-name': 'The Cloud in Trousers',
            'poem_set-1-name': 'I',
            'poem_set-2-name': '',
        }

        poet = Poet.objects.create(name='Vladimir Mayakovsky')
        formset = PoemFormSet(data=data, instance=poet)
        self.assertTrue(formset.is_valid())

        saved = formset.save()
        self.assertEqual(len(saved), 2)
        poem1, poem2 = saved
        self.assertEqual(poem1.name, 'Brooklyn Bridge')
        self.assertEqual(poem2.name, 'Brooklyn Bridge')

        # We can provide a custom queryset to our InlineFormSet:

        custom_qs = Book.objects.order_by('-title')
        formset = AuthorBooksFormSet(instance=author, queryset=custom_qs)
        self.assertEqual(len(formset.forms), 5)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_book_set-0-title">Title:</label>'
            '<input id="id_book_set-0-title" type="text" name="book_set-0-title" '
            'value="Les Paradis Artificiels" maxlength="100">'
            '<input type="hidden" name="book_set-0-author" value="1" id="id_book_set-0-author">'
            '<input type="hidden" name="book_set-0-id" value="1" id="id_book_set-0-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_book_set-1-title">Title:</label>'
            '<input id="id_book_set-1-title" type="text" name="book_set-1-title" '
            'value="Les Fleurs du Mal" maxlength="100">'
            '<input type="hidden" name="book_set-1-author" value="1" id="id_book_set-1-author">'
            '<input type="hidden" name="book_set-1-id" value="2" id="id_book_set-1-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_book_set-2-title">Title:</label>'
            '<input id="id_book_set-2-title" type="text" name="book_set-2-title" '
            'value="Flowers of Evil" maxlength="100">'
            '<input type="hidden" name="book_set-2-author" value="1" id="id_book_set-2-author">'
            '<input type="hidden" name="book_set-2-id" value="3" id="id_book_set-2-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[3].as_p(),
            '<p><label for="id_book_set-3-title">Title:</label>'
            '<input id="id_book_set-3-title" type="text" name="book_set-3-title" maxlength="100">'
            '<input type="hidden" name="book_set-3-author" value="1" id="id_book_set-3-author">'
            '<input type="hidden" name="book_set-3-id" id="id_book_set-3-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[4].as_p(),
            '<p><label for="id_book_set-4-title">Title:</label>'
            '<input id="id_book_set-4-title" type="text" name="book_set-4-title" maxlength="100">'
            '<input type="hidden" name="book_set-4-author" value="1" id="id_book_set-4-author">'
            '<input type="hidden" name="book_set-4-id" id="id_book_set-4-id"></p>'
        )

        data = {
            'book_set-TOTAL_FORMS': '5',  # the number of forms rendered
            'book_set-INITIAL_FORMS': '3',  # the number of forms with initial data
            'book_set-MAX_NUM_FORMS': '',  # the max number of forms
            'book_set-0-id': str(book1.id),
            'book_set-0-title': 'Les Paradis Artificiels',
            'book_set-1-id': str(book2.id),
            'book_set-1-title': 'Les Fleurs du Mal',
            'book_set-2-id': str(book3.id),
            'book_set-2-title': 'Flowers of Evil',
            'book_set-3-title': 'Revue des deux mondes',
            'book_set-4-title': '',
        }
        formset = AuthorBooksFormSet(data, instance=author, queryset=custom_qs)
        self.assertTrue(formset.is_valid())

        custom_qs = Book.objects.filter(title__startswith='F')
        formset = AuthorBooksFormSet(instance=author, queryset=custom_qs)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_book_set-0-title">Title:</label>'
            '<input id="id_book_set-0-title" type="text" name="book_set-0-title" '
            'value="Flowers of Evil" maxlength="100">'
            '<input type="hidden" name="book_set-0-author" value="1" id="id_book_set-0-author">'
            '<input type="hidden" name="book_set-0-id" value="3" id="id_book_set-0-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_book_set-1-title">Title:</label>'
            '<input id="id_book_set-1-title" type="text" name="book_set-1-title" maxlength="100">'
            '<input type="hidden" name="book_set-1-author" value="1" id="id_book_set-1-author">'
            '<input type="hidden" name="book_set-1-id" id="id_book_set-1-id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_book_set-2-title">Title:</label>'
            '<input id="id_book_set-2-title" type="text" name="book_set-2-title" maxlength="100">'
            '<input type="hidden" name="book_set-2-author" value="1" id="id_book_set-2-author">'
            '<input type="hidden" name="book_set-2-id" id="id_book_set-2-id"></p>'
        )

        data = {
            'book_set-TOTAL_FORMS': '3',  # the number of forms rendered
            'book_set-INITIAL_FORMS': '1',  # the number of forms with initial data
            'book_set-MAX_NUM_FORMS': '',  # the max number of forms
            'book_set-0-id': str(book3.id),
            'book_set-0-title': 'Flowers of Evil',
            'book_set-1-title': 'Revue des deux mondes',
            'book_set-2-title': '',
        }
        formset = AuthorBooksFormSet(data, instance=author, queryset=custom_qs)
        self.assertTrue(formset.is_valid())

    def test_inline_formsets_with_custom_save_method_related_instance(self):
        """
        The ModelForm.save() method should be able to access the related object
        if it exists in the database (#24395).
        """
        class PoemForm2(forms.ModelForm):
            def save(self, commit=True):
                poem = super().save(commit=False)
                poem.name = "%s by %s" % (poem.name, poem.poet.name)
                if commit:
                    poem.save()
                return poem

        PoemFormSet = inlineformset_factory(Poet, Poem, form=PoemForm2, fields="__all__")
        data = {
            'poem_set-TOTAL_FORMS': '1',
            'poem_set-INITIAL_FORMS': '0',
            'poem_set-MAX_NUM_FORMS': '',
            'poem_set-0-name': 'Le Lac',
        }
        poet = Poet()
        formset = PoemFormSet(data=data, instance=poet)
        self.assertTrue(formset.is_valid())

        # The Poet instance is saved after the formset instantiation. This
        # happens in admin's changeform_view() when adding a new object and
        # some inlines in the same request.
        poet.name = 'Lamartine'
        poet.save()
        poem = formset.save()[0]
        self.assertEqual(poem.name, 'Le Lac by Lamartine')

    def test_inline_formsets_with_wrong_fk_name(self):
        """ Regression for #23451 """
        message = "fk_name 'title' is not a ForeignKey to 'model_formsets.Author'."
        with self.assertRaisesMessage(ValueError, message):
            inlineformset_factory(Author, Book, fields="__all__", fk_name='title')

    def test_custom_pk(self):
        # We need to ensure that it is displayed

        CustomPrimaryKeyFormSet = modelformset_factory(CustomPrimaryKey, fields="__all__")
        formset = CustomPrimaryKeyFormSet()
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-my_pk">My pk:</label> <input id="id_form-0-my_pk" type="text" '
            'name="form-0-my_pk" maxlength="10"></p>'
            '<p><label for="id_form-0-some_field">Some field:</label>'
            '<input id="id_form-0-some_field" type="text" name="form-0-some_field" maxlength="100"></p>'
        )

        # Custom primary keys with ForeignKey, OneToOneField and AutoField ############

        place = Place.objects.create(pk=1, name='Giordanos', city='Chicago')

        FormSet = inlineformset_factory(Place, Owner, extra=2, can_delete=False, fields="__all__")
        formset = FormSet(instance=place)
        self.assertEqual(len(formset.forms), 2)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_owner_set-0-name">Name:</label>'
            '<input id="id_owner_set-0-name" type="text" name="owner_set-0-name" maxlength="100">'
            '<input type="hidden" name="owner_set-0-place" value="1" id="id_owner_set-0-place">'
            '<input type="hidden" name="owner_set-0-auto_id" id="id_owner_set-0-auto_id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_owner_set-1-name">Name:</label>'
            '<input id="id_owner_set-1-name" type="text" name="owner_set-1-name" maxlength="100">'
            '<input type="hidden" name="owner_set-1-place" value="1" id="id_owner_set-1-place">'
            '<input type="hidden" name="owner_set-1-auto_id" id="id_owner_set-1-auto_id"></p>'
        )

        data = {
            'owner_set-TOTAL_FORMS': '2',
            'owner_set-INITIAL_FORMS': '0',
            'owner_set-MAX_NUM_FORMS': '',
            'owner_set-0-auto_id': '',
            'owner_set-0-name': 'Joe Perry',
            'owner_set-1-auto_id': '',
            'owner_set-1-name': '',
        }
        formset = FormSet(data, instance=place)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        owner1, = saved
        self.assertEqual(owner1.name, 'Joe Perry')
        self.assertEqual(owner1.place.name, 'Giordanos')

        formset = FormSet(instance=place)
        self.assertEqual(len(formset.forms), 3)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_owner_set-0-name">Name:</label>'
            '<input id="id_owner_set-0-name" type="text" name="owner_set-0-name" value="Joe Perry" maxlength="100">'
            '<input type="hidden" name="owner_set-0-place" value="1" id="id_owner_set-0-place">'
            '<input type="hidden" name="owner_set-0-auto_id" value="%d" id="id_owner_set-0-auto_id"></p>'
            % owner1.auto_id
        )
        self.assertHTMLEqual(
            formset.forms[1].as_p(),
            '<p><label for="id_owner_set-1-name">Name:</label>'
            '<input id="id_owner_set-1-name" type="text" name="owner_set-1-name" maxlength="100">'
            '<input type="hidden" name="owner_set-1-place" value="1" id="id_owner_set-1-place">'
            '<input type="hidden" name="owner_set-1-auto_id" id="id_owner_set-1-auto_id"></p>'
        )
        self.assertHTMLEqual(
            formset.forms[2].as_p(),
            '<p><label for="id_owner_set-2-name">Name:</label>'
            '<input id="id_owner_set-2-name" type="text" name="owner_set-2-name" maxlength="100">'
            '<input type="hidden" name="owner_set-2-place" value="1" id="id_owner_set-2-place">'
            '<input type="hidden" name="owner_set-2-auto_id" id="id_owner_set-2-auto_id"></p>'
        )

        data = {
            'owner_set-TOTAL_FORMS': '3',
            'owner_set-INITIAL_FORMS': '1',
            'owner_set-MAX_NUM_FORMS': '',
            'owner_set-0-auto_id': str(owner1.auto_id),
            'owner_set-0-name': 'Joe Perry',
            'owner_set-1-auto_id': '',
            'owner_set-1-name': 'Jack Berry',
            'owner_set-2-auto_id': '',
            'owner_set-2-name': '',
        }
        formset = FormSet(data, instance=place)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        owner2, = saved
        self.assertEqual(owner2.name, 'Jack Berry')
        self.assertEqual(owner2.place.name, 'Giordanos')

        # Ensure a custom primary key that is a ForeignKey or OneToOneField get rendered for the user to choose.

        FormSet = modelformset_factory(OwnerProfile, fields="__all__")
        formset = FormSet()
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_form-0-owner">Owner:</label>'
            '<select name="form-0-owner" id="id_form-0-owner">'
            '<option value="" selected>---------</option>'
            '<option value="%d">Joe Perry at Giordanos</option>'
            '<option value="%d">Jack Berry at Giordanos</option>'
            '</select></p>'
            '<p><label for="id_form-0-age">Age:</label>'
            '<input type="number" name="form-0-age" id="id_form-0-age" min="0"></p>'
            % (owner1.auto_id, owner2.auto_id)
        )

        owner1 = Owner.objects.get(name='Joe Perry')
        FormSet = inlineformset_factory(Owner, OwnerProfile, max_num=1, can_delete=False, fields="__all__")
        self.assertEqual(FormSet.max_num, 1)

        formset = FormSet(instance=owner1)
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_ownerprofile-0-age">Age:</label>'
            '<input type="number" name="ownerprofile-0-age" id="id_ownerprofile-0-age" min="0">'
            '<input type="hidden" name="ownerprofile-0-owner" value="%d" id="id_ownerprofile-0-owner"></p>'
            % owner1.auto_id
        )

        data = {
            'ownerprofile-TOTAL_FORMS': '1',
            'ownerprofile-INITIAL_FORMS': '0',
            'ownerprofile-MAX_NUM_FORMS': '1',
            'ownerprofile-0-owner': '',
            'ownerprofile-0-age': '54',
        }
        formset = FormSet(data, instance=owner1)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        profile1, = saved
        self.assertEqual(profile1.owner, owner1)
        self.assertEqual(profile1.age, 54)

        formset = FormSet(instance=owner1)
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_ownerprofile-0-age">Age:</label>'
            '<input type="number" name="ownerprofile-0-age" value="54" id="id_ownerprofile-0-age" min="0">'
            '<input type="hidden" name="ownerprofile-0-owner" value="%d" id="id_ownerprofile-0-owner"></p>'
            % owner1.auto_id
        )

        data = {
            'ownerprofile-TOTAL_FORMS': '1',
            'ownerprofile-INITIAL_FORMS': '1',
            'ownerprofile-MAX_NUM_FORMS': '1',
            'ownerprofile-0-owner': str(owner1.auto_id),
            'ownerprofile-0-age': '55',
        }
        formset = FormSet(data, instance=owner1)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        profile1, = saved
        self.assertEqual(profile1.owner, owner1)
        self.assertEqual(profile1.age, 55)

    def test_unique_true_enforces_max_num_one(self):
        # ForeignKey with unique=True should enforce max_num=1

        place = Place.objects.create(pk=1, name='Giordanos', city='Chicago')

        FormSet = inlineformset_factory(Place, Location, can_delete=False, fields="__all__")
        self.assertEqual(FormSet.max_num, 1)

        formset = FormSet(instance=place)
        self.assertEqual(len(formset.forms), 1)
        self.assertHTMLEqual(
            formset.forms[0].as_p(),
            '<p><label for="id_location_set-0-lat">Lat:</label>'
            '<input id="id_location_set-0-lat" type="text" name="location_set-0-lat" maxlength="100"></p>'
            '<p><label for="id_location_set-0-lon">Lon:</label> '
            '<input id="id_location_set-0-lon" type="text" name="location_set-0-lon" maxlength="100">'
            '<input type="hidden" name="location_set-0-place" value="1" id="id_location_set-0-place">'
            '<input type="hidden" name="location_set-0-id" id="id_location_set-0-id"></p>'
        )

    def test_foreign_keys_in_parents(self):
        self.assertEqual(type(_get_foreign_key(Restaurant, Owner)), models.ForeignKey)
        self.assertEqual(type(_get_foreign_key(MexicanRestaurant, Owner)), models.ForeignKey)

    def test_unique_validation(self):
        FormSet = modelformset_factory(Product, fields="__all__", extra=1)
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',
            'form-0-slug': 'car-red',
        }
        formset = FormSet(data)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        product1, = saved
        self.assertEqual(product1.slug, 'car-red')

        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',
            'form-0-slug': 'car-red',
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.errors, [{'slug': ['Product with this Slug already exists.']}])

    def test_modelformset_validate_max_flag(self):
        # If validate_max is set and max_num is less than TOTAL_FORMS in the
        # data, then throw an exception. MAX_NUM_FORMS in the data is
        # irrelevant here (it's output as a hint for the client but its
        # value in the returned data is not checked)

        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '2',  # should be ignored
            'form-0-price': '12.00',
            'form-0-quantity': '1',
            'form-1-price': '24.00',
            'form-1-quantity': '2',
        }

        FormSet = modelformset_factory(Price, fields="__all__", extra=1, max_num=1, validate_max=True)
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.non_form_errors(), ['Please submit at most 1 form.'])

        # Now test the same thing without the validate_max flag to ensure
        # default behavior is unchanged
        FormSet = modelformset_factory(Price, fields="__all__", extra=1, max_num=1)
        formset = FormSet(data)
        self.assertTrue(formset.is_valid())

    def test_modelformset_min_num_equals_max_num_less_than(self):
        data = {
            'form-TOTAL_FORMS': '3',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '2',
            'form-0-slug': 'car-red',
            'form-1-slug': 'car-blue',
            'form-2-slug': 'car-black',
        }
        FormSet = modelformset_factory(
            Product,
            fields='__all__',
            extra=1,
            max_num=2,
            validate_max=True,
            min_num=2,
            validate_min=True,
        )
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.non_form_errors(), ['Please submit at most 2 forms.'])

    def test_modelformset_min_num_equals_max_num_more_than(self):
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '2',
            'form-0-slug': 'car-red',
        }
        FormSet = modelformset_factory(
            Product,
            fields='__all__',
            extra=1,
            max_num=2,
            validate_max=True,
            min_num=2,
            validate_min=True,
        )
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.non_form_errors(), ['Please submit at least 2 forms.'])

    def test_unique_together_validation(self):
        FormSet = modelformset_factory(Price, fields="__all__", extra=1)
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',
            'form-0-price': '12.00',
            'form-0-quantity': '1',
        }
        formset = FormSet(data)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        price1, = saved
        self.assertEqual(price1.price, Decimal('12.00'))
        self.assertEqual(price1.quantity, 1)

        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',
            'form-0-price': '12.00',
            'form-0-quantity': '1',
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.errors, [{'__all__': ['Price with this Price and Quantity already exists.']}])

    def test_unique_together_with_inlineformset_factory(self):
        # Also see bug #8882.

        repository = Repository.objects.create(name='Test Repo')
        FormSet = inlineformset_factory(Repository, Revision, extra=1, fields="__all__")
        data = {
            'revision_set-TOTAL_FORMS': '1',
            'revision_set-INITIAL_FORMS': '0',
            'revision_set-MAX_NUM_FORMS': '',
            'revision_set-0-repository': repository.pk,
            'revision_set-0-revision': '146239817507f148d448db38840db7c3cbf47c76',
            'revision_set-0-DELETE': '',
        }
        formset = FormSet(data, instance=repository)
        self.assertTrue(formset.is_valid())
        saved = formset.save()
        self.assertEqual(len(saved), 1)
        revision1, = saved
        self.assertEqual(revision1.repository, repository)
        self.assertEqual(revision1.revision, '146239817507f148d448db38840db7c3cbf47c76')

        # attempt to save the same revision against the same repo.
        data = {
            'revision_set-TOTAL_FORMS': '1',
            'revision_set-INITIAL_FORMS': '0',
            'revision_set-MAX_NUM_FORMS': '',
            'revision_set-0-repository': repository.pk,
            'revision_set-0-revision': '146239817507f148d448db38840db7c3cbf47c76',
            'revision_set-0-DELETE': '',
        }
        formset = FormSet(data, instance=repository)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset.errors, [{'__all__': ['Revision with this Repository and Revision already exists.']}])

        # unique_together with inlineformset_factory with overridden form fields
        # Also see #9494

        FormSet = inlineformset_factory(Repository, Revision, fields=('revision',), extra=1)
        data = {
            'revision_set-TOTAL_FORMS': '1',
            'revision_set-INITIAL_FORMS': '0',
            'revision_set-MAX_NUM_FORMS': '',
            'revision_set-0-repository': repository.pk,
            'revision_set-0-revision': '146239817507f148d448db38840db7c3cbf47c76',
            'revision_set-0-DELETE': '',
        }
        formset = FormSet(data, instance=repository)
        self.assertFalse(formset.is_valid())

    def test_callable_defaults(self):
        # Use of callable defaults (see bug #7975).

        person = Person.objects.create(name='Ringo')
        FormSet = inlineformset_factory(Person, Membership, can_delete=False, extra=1, fields="__all__")
        formset = FormSet(instance=person)

        # Django will render a hidden field for model fields that have a callable
        # default. This is required to ensure the value is tested for change correctly
        # when determine what extra forms have changed to save.

        self.assertEqual(len(formset.forms), 1)  # this formset only has one form
        form = formset.forms[0]
        now = form.fields['date_joined'].initial()
        result = form.as_p()
        result = re.sub(r'[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}(?:\.[0-9]+)?', '__DATETIME__', result)
        self.assertHTMLEqual(
            result,
            '<p><label for="id_membership_set-0-date_joined">Date joined:</label>'
            '<input type="text" name="membership_set-0-date_joined" '
            'value="__DATETIME__" id="id_membership_set-0-date_joined">'
            '<input type="hidden" name="initial-membership_set-0-date_joined" value="__DATETIME__" '
            'id="initial-membership_set-0-id_membership_set-0-date_joined"></p>'
            '<p><label for="id_membership_set-0-karma">Karma:</label>'
            '<input type="number" name="membership_set-0-karma" id="id_membership_set-0-karma">'
            '<input type="hidden" name="membership_set-0-person" value="%d" id="id_membership_set-0-person">'
            '<input type="hidden" name="membership_set-0-id" id="id_membership_set-0-id"></p>'
            % person.id)

        # test for validation with callable defaults. Validations rely on hidden fields

        data = {
            'membership_set-TOTAL_FORMS': '1',
            'membership_set-INITIAL_FORMS': '0',
            'membership_set-MAX_NUM_FORMS': '',
            'membership_set-0-date_joined': now.strftime('%Y-%m-%d %H:%M:%S'),
            'initial-membership_set-0-date_joined': now.strftime('%Y-%m-%d %H:%M:%S'),
            'membership_set-0-karma': '',
        }
        formset = FormSet(data, instance=person)
        self.assertTrue(formset.is_valid())

        # now test for when the data changes

        one_day_later = now + datetime.timedelta(days=1)
        filled_data = {
            'membership_set-TOTAL_FORMS': '1',
            'membership_set-INITIAL_FORMS': '0',
            'membership_set-MAX_NUM_FORMS': '',
            'membership_set-0-date_joined': one_day_later.strftime('%Y-%m-%d %H:%M:%S'),
            'initial-membership_set-0-date_joined': now.strftime('%Y-%m-%d %H:%M:%S'),
            'membership_set-0-karma': '',
        }
        formset = FormSet(filled_data, instance=person)
        self.assertFalse(formset.is_valid())

        # now test with split datetime fields

        class MembershipForm(forms.ModelForm):
            date_joined = forms.SplitDateTimeField(initial=now)

            class Meta:
                model = Membership
                fields = "__all__"

            def __init__(self, **kwargs):
                super().__init__(**kwargs)
                self.fields['date_joined'].widget = forms.SplitDateTimeWidget()

        FormSet = inlineformset_factory(
            Person,
            Membership,
            form=MembershipForm,
            can_delete=False,
            extra=1,
            fields="__all__",
        )
        data = {
            'membership_set-TOTAL_FORMS': '1',
            'membership_set-INITIAL_FORMS': '0',
            'membership_set-MAX_NUM_FORMS': '',
            'membership_set-0-date_joined_0': now.strftime('%Y-%m-%d'),
            'membership_set-0-date_joined_1': now.strftime('%H:%M:%S'),
            'initial-membership_set-0-date_joined': now.strftime('%Y-%m-%d %H:%M:%S'),
            'membership_set-0-karma': '',
        }
        formset = FormSet(data, instance=person)
        self.assertTrue(formset.is_valid())

    def test_inlineformset_factory_with_null_fk(self):
        # inlineformset_factory tests with fk having null=True. see #9462.
        # create some data that will exhibit the issue
        team = Team.objects.create(name="Red Vipers")
        Player(name="Timmy").save()
        Player(name="Bobby", team=team).save()

        PlayerInlineFormSet = inlineformset_factory(Team, Player, fields="__all__")
        formset = PlayerInlineFormSet()
        self.assertQuerysetEqual(formset.get_queryset(), [])

        formset = PlayerInlineFormSet(instance=team)
        players = formset.get_queryset()
        self.assertEqual(len(players), 1)
        player1, = players
        self.assertEqual(player1.team, team)
        self.assertEqual(player1.name, 'Bobby')

    def test_inlineformset_with_arrayfield(self):
        class SimpleArrayField(forms.CharField):
            """A proxy for django.contrib.postgres.forms.SimpleArrayField."""
            def to_python(self, value):
                value = super().to_python(value)
                return value.split(',') if value else []

        class BookForm(forms.ModelForm):
            title = SimpleArrayField()

            class Meta:
                model = Book
                fields = ('title',)

        BookFormSet = inlineformset_factory(Author, Book, form=BookForm)
        data = {
            'book_set-TOTAL_FORMS': '3',
            'book_set-INITIAL_FORMS': '0',
            'book_set-MAX_NUM_FORMS': '',
            'book_set-0-title': 'test1,test2',
            'book_set-1-title': 'test1,test2',
            'book_set-2-title': 'test3,test4',
        }
        author = Author.objects.create(name='test')
        formset = BookFormSet(data, instance=author)
        self.assertEqual(formset.errors, [{}, {'__all__': ['Please correct the duplicate values below.']}, {}])

    def test_model_formset_with_custom_pk(self):
        # a formset for a Model that has a custom primary key that still needs to be
        # added to the formset automatically
        FormSet = modelformset_factory(ClassyMexicanRestaurant, fields=["tacos_are_yummy"])
        self.assertEqual(sorted(FormSet().forms[0].fields), ['tacos_are_yummy', 'the_restaurant'])

    def test_model_formset_with_initial_model_instance(self):
        # has_changed should compare model instance and primary key
        # see #18898
        FormSet = modelformset_factory(Poem, fields='__all__')
        john_milton = Poet(name="John Milton")
        john_milton.save()
        data = {
            'form-TOTAL_FORMS': 1,
            'form-INITIAL_FORMS': 0,
            'form-MAX_NUM_FORMS': '',
            'form-0-name': '',
            'form-0-poet': str(john_milton.id),
        }
        formset = FormSet(initial=[{'poet': john_milton}], data=data)
        self.assertFalse(formset.extra_forms[0].has_changed())

    def test_model_formset_with_initial_queryset(self):
        # has_changed should work with queryset and list of pk's
        # see #18898
        FormSet = modelformset_factory(AuthorMeeting, fields='__all__')
        Author.objects.create(pk=1, name='Charles Baudelaire')
        data = {
            'form-TOTAL_FORMS': 1,
            'form-INITIAL_FORMS': 0,
            'form-MAX_NUM_FORMS': '',
            'form-0-name': '',
            'form-0-created': '',
            'form-0-authors': list(Author.objects.values_list('id', flat=True)),
        }
        formset = FormSet(initial=[{'authors': Author.objects.all()}], data=data)
        self.assertFalse(formset.extra_forms[0].has_changed())

    def test_prevent_duplicates_from_with_the_same_formset(self):
        FormSet = modelformset_factory(Product, fields="__all__", extra=2)
        data = {
            'form-TOTAL_FORMS': 2,
            'form-INITIAL_FORMS': 0,
            'form-MAX_NUM_FORMS': '',
            'form-0-slug': 'red_car',
            'form-1-slug': 'red_car',
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset._non_form_errors, ['Please correct the duplicate data for slug.'])

        FormSet = modelformset_factory(Price, fields="__all__", extra=2)
        data = {
            'form-TOTAL_FORMS': 2,
            'form-INITIAL_FORMS': 0,
            'form-MAX_NUM_FORMS': '',
            'form-0-price': '25',
            'form-0-quantity': '7',
            'form-1-price': '25',
            'form-1-quantity': '7',
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(
            formset._non_form_errors,
            ['Please correct the duplicate data for price and quantity, which must be unique.']
        )

        # Only the price field is specified, this should skip any unique checks since
        # the unique_together is not fulfilled. This will fail with a KeyError if broken.
        FormSet = modelformset_factory(Price, fields=("price",), extra=2)
        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',
            'form-0-price': '24',
            'form-1-price': '24',
        }
        formset = FormSet(data)
        self.assertTrue(formset.is_valid())

        FormSet = inlineformset_factory(Author, Book, extra=0, fields="__all__")
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        Book.objects.create(pk=1, author=author, title='Les Paradis Artificiels')
        Book.objects.create(pk=2, author=author, title='Les Fleurs du Mal')
        Book.objects.create(pk=3, author=author, title='Flowers of Evil')

        book_ids = author.book_set.order_by('id').values_list('id', flat=True)
        data = {
            'book_set-TOTAL_FORMS': '2',
            'book_set-INITIAL_FORMS': '2',
            'book_set-MAX_NUM_FORMS': '',

            'book_set-0-title': 'The 2008 Election',
            'book_set-0-author': str(author.id),
            'book_set-0-id': str(book_ids[0]),

            'book_set-1-title': 'The 2008 Election',
            'book_set-1-author': str(author.id),
            'book_set-1-id': str(book_ids[1]),
        }
        formset = FormSet(data=data, instance=author)
        self.assertFalse(formset.is_valid())
        self.assertEqual(formset._non_form_errors, ['Please correct the duplicate data for title.'])
        self.assertEqual(formset.errors, [{}, {'__all__': ['Please correct the duplicate values below.']}])

        FormSet = modelformset_factory(Post, fields="__all__", extra=2)
        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',

            'form-0-title': 'blah',
            'form-0-slug': 'Morning',
            'form-0-subtitle': 'foo',
            'form-0-posted': '2009-01-01',
            'form-1-title': 'blah',
            'form-1-slug': 'Morning in Prague',
            'form-1-subtitle': 'rawr',
            'form-1-posted': '2009-01-01'
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(
            formset._non_form_errors,
            ['Please correct the duplicate data for title which must be unique for the date in posted.']
        )
        self.assertEqual(
            formset.errors,
            [{}, {'__all__': ['Please correct the duplicate values below.']}]
        )

        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',

            'form-0-title': 'foo',
            'form-0-slug': 'Morning in Prague',
            'form-0-subtitle': 'foo',
            'form-0-posted': '2009-01-01',
            'form-1-title': 'blah',
            'form-1-slug': 'Morning in Prague',
            'form-1-subtitle': 'rawr',
            'form-1-posted': '2009-08-02'
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(
            formset._non_form_errors,
            ['Please correct the duplicate data for slug which must be unique for the year in posted.']
        )

        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '',

            'form-0-title': 'foo',
            'form-0-slug': 'Morning in Prague',
            'form-0-subtitle': 'rawr',
            'form-0-posted': '2008-08-01',
            'form-1-title': 'blah',
            'form-1-slug': 'Prague',
            'form-1-subtitle': 'rawr',
            'form-1-posted': '2009-08-02'
        }
        formset = FormSet(data)
        self.assertFalse(formset.is_valid())
        self.assertEqual(
            formset._non_form_errors,
            ['Please correct the duplicate data for subtitle which must be unique for the month in posted.']
        )

    def test_prevent_change_outer_model_and_create_invalid_data(self):
        author = Author.objects.create(name='Charles')
        other_author = Author.objects.create(name='Walt')
        AuthorFormSet = modelformset_factory(Author, fields='__all__')
        data = {
            'form-TOTAL_FORMS': '2',
            'form-INITIAL_FORMS': '2',
            'form-MAX_NUM_FORMS': '',
            'form-0-id': str(author.id),
            'form-0-name': 'Charles',
            'form-1-id': str(other_author.id),  # A model not in the formset's queryset.
            'form-1-name': 'Changed name',
        }
        # This formset is only for Walt Whitman and shouldn't accept data for
        # other_author.
        formset = AuthorFormSet(data=data, queryset=Author.objects.filter(id__in=(author.id,)))
        self.assertTrue(formset.is_valid())
        formset.save()
        # The name of other_author shouldn't be changed and new models aren't
        # created.
        self.assertQuerysetEqual(Author.objects.all(), ['<Author: Charles>', '<Author: Walt>'])

    def test_validation_without_id(self):
        AuthorFormSet = modelformset_factory(Author, fields='__all__')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '',
            'form-0-name': 'Charles',
        }
        formset = AuthorFormSet(data)
        self.assertEqual(
            formset.errors,
            [{'id': ['This field is required.']}],
        )

    def test_validation_with_child_model_without_id(self):
        BetterAuthorFormSet = modelformset_factory(BetterAuthor, fields='__all__')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '',
            'form-0-name': 'Charles',
            'form-0-write_speed': '10',
        }
        formset = BetterAuthorFormSet(data)
        self.assertEqual(
            formset.errors,
            [{'author_ptr': ['This field is required.']}],
        )

    def test_validation_with_invalid_id(self):
        AuthorFormSet = modelformset_factory(Author, fields='__all__')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '',
            'form-0-id': 'abc',
            'form-0-name': 'Charles',
        }
        formset = AuthorFormSet(data)
        self.assertEqual(
            formset.errors,
            [{'id': ['Select a valid choice. That choice is not one of the available choices.']}],
        )

    def test_validation_with_nonexistent_id(self):
        AuthorFormSet = modelformset_factory(Author, fields='__all__')
        data = {
            'form-TOTAL_FORMS': '1',
            'form-INITIAL_FORMS': '1',
            'form-MAX_NUM_FORMS': '',
            'form-0-id': '12345',
            'form-0-name': 'Charles',
        }
        formset = AuthorFormSet(data)
        self.assertEqual(
            formset.errors,
            [{'id': ['Select a valid choice. That choice is not one of the available choices.']}],
        )

    def test_initial_form_count_empty_data_raises_validation_error(self):
        AuthorFormSet = modelformset_factory(Author, fields='__all__')
        msg = 'ManagementForm data is missing or has been tampered with'
        with self.assertRaisesMessage(ValidationError, msg):
            AuthorFormSet({}).initial_form_count()


class TestModelFormsetOverridesTroughFormMeta(TestCase):
    def test_modelformset_factory_widgets(self):
        widgets = {
            'name': forms.TextInput(attrs={'class': 'poet'})
        }
        PoetFormSet = modelformset_factory(Poet, fields="__all__", widgets=widgets)
        form = PoetFormSet.form()
        self.assertHTMLEqual(
            str(form['name']),
            '<input id="id_name" maxlength="100" type="text" class="poet" name="name" required>'
        )

    def test_inlineformset_factory_widgets(self):
        widgets = {
            'title': forms.TextInput(attrs={'class': 'book'})
        }
        BookFormSet = inlineformset_factory(Author, Book, widgets=widgets, fields="__all__")
        form = BookFormSet.form()
        self.assertHTMLEqual(
            str(form['title']),
            '<input class="book" id="id_title" maxlength="100" name="title" type="text" required>'
        )

    def test_modelformset_factory_labels_overrides(self):
        BookFormSet = modelformset_factory(Book, fields="__all__", labels={
            'title': 'Name'
        })
        form = BookFormSet.form()
        self.assertHTMLEqual(form['title'].label_tag(), '<label for="id_title">Name:</label>')

    def test_inlineformset_factory_labels_overrides(self):
        BookFormSet = inlineformset_factory(Author, Book, fields="__all__", labels={
            'title': 'Name'
        })
        form = BookFormSet.form()
        self.assertHTMLEqual(form['title'].label_tag(), '<label for="id_title">Name:</label>')

    def test_modelformset_factory_help_text_overrides(self):
        BookFormSet = modelformset_factory(Book, fields="__all__", help_texts={
            'title': 'Choose carefully.'
        })
        form = BookFormSet.form()
        self.assertEqual(form['title'].help_text, 'Choose carefully.')

    def test_inlineformset_factory_help_text_overrides(self):
        BookFormSet = inlineformset_factory(Author, Book, fields="__all__", help_texts={
            'title': 'Choose carefully.'
        })
        form = BookFormSet.form()
        self.assertEqual(form['title'].help_text, 'Choose carefully.')

    def test_modelformset_factory_error_messages_overrides(self):
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        BookFormSet = modelformset_factory(Book, fields="__all__", error_messages={
            'title': {
                'max_length': 'Title too long!!'
            }
        })
        form = BookFormSet.form(data={'title': 'Foo ' * 30, 'author': author.id})
        form.full_clean()
        self.assertEqual(form.errors, {'title': ['Title too long!!']})

    def test_inlineformset_factory_error_messages_overrides(self):
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        BookFormSet = inlineformset_factory(Author, Book, fields="__all__", error_messages={
            'title': {
                'max_length': 'Title too long!!'
            }
        })
        form = BookFormSet.form(data={'title': 'Foo ' * 30, 'author': author.id})
        form.full_clean()
        self.assertEqual(form.errors, {'title': ['Title too long!!']})

    def test_modelformset_factory_field_class_overrides(self):
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        BookFormSet = modelformset_factory(Book, fields="__all__", field_classes={
            'title': forms.SlugField,
        })
        form = BookFormSet.form(data={'title': 'Foo ' * 30, 'author': author.id})
        self.assertIs(Book._meta.get_field('title').__class__, models.CharField)
        self.assertIsInstance(form.fields['title'], forms.SlugField)

    def test_inlineformset_factory_field_class_overrides(self):
        author = Author.objects.create(pk=1, name='Charles Baudelaire')
        BookFormSet = inlineformset_factory(Author, Book, fields="__all__", field_classes={
            'title': forms.SlugField,
        })
        form = BookFormSet.form(data={'title': 'Foo ' * 30, 'author': author.id})
        self.assertIs(Book._meta.get_field('title').__class__, models.CharField)
        self.assertIsInstance(form.fields['title'], forms.SlugField)

    def test_modelformset_factory_absolute_max(self):
        AuthorFormSet = modelformset_factory(Author, fields='__all__', absolute_max=1500)
        data = {
            'form-TOTAL_FORMS': '1501',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '0',
        }
        formset = AuthorFormSet(data=data)
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(len(formset.forms), 1500)
        self.assertEqual(
            formset.non_form_errors(),
            ['Please submit at most 1000 forms.'],
        )

    def test_modelformset_factory_absolute_max_with_max_num(self):
        AuthorFormSet = modelformset_factory(
            Author,
            fields='__all__',
            max_num=20,
            absolute_max=100,
        )
        data = {
            'form-TOTAL_FORMS': '101',
            'form-INITIAL_FORMS': '0',
            'form-MAX_NUM_FORMS': '0',
        }
        formset = AuthorFormSet(data=data)
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(len(formset.forms), 100)
        self.assertEqual(
            formset.non_form_errors(),
            ['Please submit at most 20 forms.'],
        )

    def test_inlineformset_factory_absolute_max(self):
        author = Author.objects.create(name='Charles Baudelaire')
        BookFormSet = inlineformset_factory(
            Author,
            Book,
            fields='__all__',
            absolute_max=1500,
        )
        data = {
            'book_set-TOTAL_FORMS': '1501',
            'book_set-INITIAL_FORMS': '0',
            'book_set-MAX_NUM_FORMS': '0',
        }
        formset = BookFormSet(data, instance=author)
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(len(formset.forms), 1500)
        self.assertEqual(
            formset.non_form_errors(),
            ['Please submit at most 1000 forms.'],
        )

    def test_inlineformset_factory_absolute_max_with_max_num(self):
        author = Author.objects.create(name='Charles Baudelaire')
        BookFormSet = inlineformset_factory(
            Author,
            Book,
            fields='__all__',
            max_num=20,
            absolute_max=100,
        )
        data = {
            'book_set-TOTAL_FORMS': '101',
            'book_set-INITIAL_FORMS': '0',
            'book_set-MAX_NUM_FORMS': '0',
        }
        formset = BookFormSet(data, instance=author)
        self.assertIs(formset.is_valid(), False)
        self.assertEqual(len(formset.forms), 100)
        self.assertEqual(
            formset.non_form_errors(),
            ['Please submit at most 20 forms.'],
        )

    def test_modelformset_factory_can_delete_extra(self):
        AuthorFormSet = modelformset_factory(
            Author,
            fields='__all__',
            can_delete=True,
            can_delete_extra=True,
            extra=2,
        )
        formset = AuthorFormSet()
        self.assertEqual(len(formset), 2)
        self.assertIn('DELETE', formset.forms[0].fields)
        self.assertIn('DELETE', formset.forms[1].fields)

    def test_modelformset_factory_disable_delete_extra(self):
        AuthorFormSet = modelformset_factory(
            Author,
            fields='__all__',
            can_delete=True,
            can_delete_extra=False,
            extra=2,
        )
        formset = AuthorFormSet()
        self.assertEqual(len(formset), 2)
        self.assertNotIn('DELETE', formset.forms[0].fields)
        self.assertNotIn('DELETE', formset.forms[1].fields)

    def test_inlineformset_factory_can_delete_extra(self):
        BookFormSet = inlineformset_factory(
            Author,
            Book,
            fields='__all__',
            can_delete=True,
            can_delete_extra=True,
            extra=2,
        )
        formset = BookFormSet()
        self.assertEqual(len(formset), 2)
        self.assertIn('DELETE', formset.forms[0].fields)
        self.assertIn('DELETE', formset.forms[1].fields)

    def test_inlineformset_factory_can_not_delete_extra(self):
        BookFormSet = inlineformset_factory(
            Author,
            Book,
            fields='__all__',
            can_delete=True,
            can_delete_extra=False,
            extra=2,
        )
        formset = BookFormSet()
        self.assertEqual(len(formset), 2)
        self.assertNotIn('DELETE', formset.forms[0].fields)
        self.assertNotIn('DELETE', formset.forms[1].fields)