How to test 500.html error page in django development env?

Question

I am using Django for a project and is already in production.

In the production environment 500.html is rendered whenever a server error occurs.

How do I tes

Answer 1

How i do and test custom error handlers

Define custom View based on TemplateView

# views.py
from django.views.generic import TemplateView

class ErrorHandler(TemplateView):

    """ Render error template """

    error_code = 404
    template_name = 'index/error.html'

    def dispatch(self, request, *args, **kwargs):
        """ For error on any methods return just GET """
        return self.get(request, *args, **kwargs)

    def get_context_data(self, **kwargs):
        context = super().get_context_data(**kwargs)
        context['error_code'] = self.error_code
        return context

    def render_to_response(self, context, **response_kwargs):
        """ Return correct status code """
        response_kwargs = response_kwargs or {}
        response_kwargs.update(status=self.error_code)
        return super().render_to_response(context, **response_kwargs)

Tell django to use custom error handlers

# urls.py

from index.views import ErrorHandler

# error handing handlers - fly binding
for code in (400, 403, 404, 500):
    vars()['handler{}'.format(code)] = ErrorHandler.as_view(error_code=code)

Testcase for custom error handlers

# tests.py

from unittest import mock

from django.test import TestCase
from django.core.exceptions import SuspiciousOperation, PermissionDenied
from django.http import Http404
from index import views

class ErrorHandlersTestCase(TestCase):

    """ Check is correct error handlers work """

    def raise_(exception):
        def wrapped(*args, **kwargs):
            raise exception('Test exception')
        return wrapped

    def test_index_page(self):
        """ Should check is 200 on index page """
        response = self.client.get('/')
        self.assertEqual(response.status_code, 200)
        self.assertTemplateUsed(response, 'index/index.html')

    @mock.patch('index.views.IndexView.get', raise_(Http404))
    def test_404_page(self):
        """ Should check is 404 page correct """
        response = self.client.get('/')
        self.assertEqual(response.status_code, 404)
        self.assertTemplateUsed(response, 'index/error.html')
        self.assertIn('404 Page not found', response.content.decode('utf-8'))

    @mock.patch('index.views.IndexView.get', views.ErrorHandler.as_view(error_code=500))
    def test_500_page(self):
        """ Should check is 500 page correct """
        response = self.client.get('/')
        self.assertEqual(response.status_code, 500)
        self.assertTemplateUsed(response, 'index/error.html')
        self.assertIn('500 Server Error', response.content.decode('utf-8'))

    @mock.patch('index.views.IndexView.get', raise_(SuspiciousOperation))
    def test_400_page(self):
        """ Should check is 400 page correct """
        response = self.client.get('/')
        self.assertEqual(response.status_code, 400)
        self.assertTemplateUsed(response, 'index/error.html')
        self.assertIn('400 Bad request', response.content.decode('utf-8'))

    @mock.patch('index.views.IndexView.get', raise_(PermissionDenied))
    def test_403_page(self):
        """ Should check is 403 page correct """
        response = self.client.get('/')
        self.assertEqual(response.status_code, 403)
        self.assertTemplateUsed(response, 'index/error.html')
        self.assertIn('403 Permission Denied', response.content.decode('utf-8'))

Answer 2

You can simply define the handler404 and handler500 for errors in your main views.py file as detailed in this answer:

https://stackoverflow.com/a/18009660/1913888

This will return the error that you desire when Django routes to that handler. No custom URL configuration is needed to route to a different URL name.

Answer 3

Are both debug settings false?

settings.DEBUG = False
settings.TEMPLATE_DEBUG = False

Answer 4

I prefer not to turn DEBUG off. Instead I put the following snippet in the urls.py:

if settings.DEBUG:
    urlpatterns += patterns('',
        (r'^500/$', 'your_custom_view_if_you_wrote_one'),
        (r'^404/$', 'django.views.generic.simple.direct_to_template', {'template': '404.html'}),
    )

In the snippet above, the error page uses a custom view, you can easily replace it with Django's direct_to_template view though.

Now you can test 500 and 404 pages by calling their urls: http://example.com/500 and http://example.com/404