Re: Unit-Testing Django Views

This is effectively failing because of a mechanism added in 1.10 to protect

against BREACH attacks[0] by salting the CSRF token.

I'm not aware of any way to disable this mechanism but testing against the

exact HTML returned from a view seems fragile.

I suggest you use assertContains[1] (with or without html=True) and

assertTemplateUsed[2] instead.

Cheers,

Simon

[0] https://docs.djangoproject.com/en/2.1/ref/csrf/#how-it-works

[1] https://docs.djangoproject.com/en/2.1/topics/testing/tools/#django.test.SimpleTestCase.assertContains

[2] https://docs.djangoproject.com/en/2.1/topics/testing/tools/#django.test.SimpleTestCase.assertTemplateUsed

Le jeudi 28 mars 2019 12:16:43 UTC-4, OnlineJudge95 a écrit :

Hi people,

I am following the book Test-Driven Development with Python by Harry J.W. Perceval. The book is using Django version 1.7 which is outdated as of now so I started with version 2.1.

I am trying to unit test my index view. One unit-test that I have written is testing whether the index view returns correct HTML or not by comparing the input received through

django.template.loader.render_to_string

the unit-test fail with the following traceback

python manage.py test

Creating test database for alias 'default'...

.System check identified no issues (0 silenced).

F.

======================================================================

FAIL: test_index_view_returns_correct_html (lists.tests.IndexViewTest)

----------------------------------------------------------------------

Traceback (most recent call last):

  File "tests.py", line 24, in test_index_view_returns_correct_html

    self.assertEqual(expected_html, actual_html)

AssertionError: '<!DO[263 chars]lue="BJMT1b9fxuXOGugp00SDypeTYZxvlmc6KtBSYMDon[198 chars]l>\n' != '<!DO[263 chars]lue="R05ZiWMASEWMurA8Rdo8bnA0mTwqFTqA0KUYfxgJI[198 chars]l>\n'

----------------------------------------------------------------------

Ran 3 tests in 0.006s

FAILED (failures=1)

Destroying test database for alias 'default'...

Process finished with exit code 1

It was clear that the csrf token is causing the test to fail. Is there any way to test it, or should it be tested? I ask this as when I changed my Django version to 1.7, the tests were passing, even after giving the csrf token field in the form. I tried going through the changelogs but 1.7 is far behind (beginner here). Please find the code snippets, directory structure provided below.

lists/views.py

from django.http import HttpResponse
from django.shortcuts import render


# Create your views here.
def index(request):
    if request.method == 'POST':
        return HttpResponse(request.POST['item_text'])
    return render(request, 'index.html')

lists/test.py

from django.http import HttpRequest
from django.template.loader import render_to_string
from django.test import TestCase
from django.urls import resolve

from lists.views import index


# Create your tests here.
class IndexViewTest(TestCase):

    def test_root_url_resolves_to_home_page_view(self):
       [...]

    def test_index_view_returns_correct_html(self):
        request = HttpRequest()
        response = index(request)
        actual_html = response.content.decode()
        expected_html = render_to_string('index.html', request=request)

        self.assertEqual(expected_html, actual_html)

    def test_index_view_can_save_a_post_request(self):
       [...]

requirements.txt

Django==2.1.7
pytz==2018.9
selenium==3.141.0
urllib3==1.24.

settings.py

[...]
# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    'lists',
]

[...]

Directory Structure

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