How to use Django reverse in tests?

Question

I don't know how to use the reverse function in django.I am getting this,

ValueError: dictionary update sequence element #0 has length 1; 2 is required

I could hardcode the urls directly that worked fine, but i wanted to do it in standard way.

main urls.py

 urlpatterns = [
            url(r'^nmailadmin/', admin.site.urls),
            url(r'^api/v1/',include('Core.Login.urls',namespace='login')),
            url(r'^api/v1/mail/',include('Core.Mail.urls',namespace='mail')),
 ]

I have given namespace for login and mail API.

When I try to access mail urls like this

def test_0list_folders(self):
    url = reverse('mail:folder_list', kwargs={'server':0})
    response = self.client.get('/api/v1/mail/folder_list/0/', follow=True)
    self.assertEqual(status.HTTP_200_OK, response.status_code)

I am getting error like this.

----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/next/PycharmProjects/Nmail/Nmail-Server/Core/Mail/tests.py", line 25, in test_0list_folders
    url = reverse('mail:folder_list', kwargs={'server':0})
  File "/home/next/venv/NmailVenv/lib/python3.6/site-packages/django/urls/base.py", line 91, in reverse
    return force_text(iri_to_uri(resolver._reverse_with_prefix(view, prefix, *args, **kwargs)))
  File "/home/next/venv/NmailVenv/lib/python3.6/site-packages/django/urls/resolvers.py", line 436, in _reverse_with_prefix
    self._populate()
  File "/home/next/venv/NmailVenv/lib/python3.6/site-packages/django/urls/resolvers.py", line 309, in _populate
    dict(defaults, **pattern.default_kwargs),
ValueError: dictionary update sequence element #0 has length 1; 2 is required

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

This is my urls file of mail app.

urlpatterns = [
   url(r'folder_list/(?P<server>\d+)/$', folder_list,name='folder_list'),
   url(r'^auth_login/$', login_auth, name='auth_login'),
   url(r'viewmsg/(?P<server>\d+)/(?P<folder>.*?)/(?P<uid>\d+)/$', viewmsg, name='viewmsg'),
    url(r'action/(?P<action>.*?)/$', action, 'action'),
     ]

Django version : Django==1.11.7

error thrown by `reverse('mail:auth_login')` but you're showing a different url pattern. list all the urls exists in `mail` namespace — Avinash Raj, Feb 08 '18 at 13:27

score 0 · Answer 1 · answered Feb 09 '18 at 10:41

My bad. I actually found out that problem is with missing kwarg name in one of my mail app's urls.py

urlpatterns = [
   url(r'folder_list/(?P<server>\d+)/$', folder_list,name='folder_list'),
   url(r'^auth_login/$', login_auth, name='auth_login'),
   url(r'viewmsg/(?P<server>\d+)/(?P<folder>.*?)/(?P<uid>\d+)/$', viewmsg, name='viewmsg'),
   url(r'action/(?P<action>.*?)/$', action, name='action'),
     ]

And it all worked fine. Hope this helps someone in future.

P.S : It was already pointed out by an answer Error: "dictionary update sequence element #0 has length 1; 2 is required" on Django 1.4.

How to use Django reverse in tests?

1 Answers1