How to test Django's UpdateView?

Question

As a simplified example, I've written an UpdateView for a Book model, as well as a ListView to redirect to upon success:

from django.urls import reverse
from django.views.generic import ListView
from django.views.generic.edit import UpdateView
from .models import Book


class BookUpdate(UpdateView):
    model = Book
    fields = ['title', 'author']


class BookList(ListView):
    model = Book

The Book model is defined as

class Book(models.Model):
    title = models.CharField(max_length=100)
    author = models.CharField(max_length=100, blank=True)

    def get_absolute_url(self):
        return reverse('books-list')

where urls.py is

from django.urls import path
from books.views import BookUpdate, BookList


urlpatterns = [
    path('books/', BookList.as_view(), name='books-list'),
    path('book/<int:pk>/', BookUpdate.as_view(), name='book-update')
]

In books/tests.py I've tried to write the following test:

class BookUpdateTest(TestCase):
    def test_update_book(self):
        book = Book.objects.create(title='The Catcher in the Rye')

        response = self.client.post(
            reverse('book-update', kwargs={'pk': book.id}), 
            {'author': 'J.D. Salinger'})

        self.assertEqual(response.status_code, 200)

        book.refresh_from_db()
        self.assertEqual(book.author, 'J.D. Salinger')

However, this test fails because the book's author appears not to be updated after the POST request, even after refreshing from the database:

FAIL: test_update_book (books.tests.BookUpdateTest)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/Users/kurtpeek/Documents/Scratch/book_project/books/tests.py", line 46, in test_update_book
    self.assertEqual(book.author, 'J.D. Salinger')
AssertionError: '' != 'J.D. Salinger'
+ J.D. Salinger

On the other hand, if I run the development server and fill out the fields manually, everything seems to work as expected. How can I write a unit test for the UpdateView which captures the user updating the fields, submitting the form, and making changes to the corresponding objects?

Answer 1

It seems that if you POST to a form, you have to post all required fields, not just the ones you are updating - even if the required field of the underlying model already has a value. Also, the status code returned upon a successful update is 302 'Found', not 200 'OK'. So the following test passes:

class BookUpdateTest(TestCase):
    def test_update_book(self):
        book = Book.objects.create(title='The Catcher in the Rye')

        response = self.client.post(
            reverse('book-update', kwargs={'pk': book.id}), 
            {'title': 'The Catcher in the Rye', 'author': 'J.D. Salinger'})

        self.assertEqual(response.status_code, 302)

        book.refresh_from_db()
        self.assertEqual(book.author, 'J.D. Salinger')