AssertionError: 301 != 200 : Couldn't retrieve redirection page

Question

When trying to access a page that requires a User to be logged in, a user should be redirected to a login page to enter their user credentials. However, when the test is ran on that case, I'm getting the AssertionError: 301 != 200 : Couldn't retrieve redirection page '/accounts/sign_in' .

I'm not clear on what is going on for this happen? Why am I getting a 301 and not a 302?

class LoginRedirectRequest(TestCase):
    '''Verify that a user is redirected to
    a login page if they are not logged in.'''

    @classmethod
    def setUpTestData(cls):
        User.objects.create_user(
            username="testuser",
            password='*Dh&M3h36v*$J*'
        )

    def test_redirect_to_login_from_edit_profile_view(self):
        response = self.client.get(
            reverse("accounts:edit_profile", kwargs={'user_id': 1})
        )
        self.assertRedirects(response, '/accounts/sign_in/?next=/accounts/profile_edit/1/')

@login_required(login_url="/accounts/sign_in")
def edit_profile(request, user_id):
    user = request.user
    user_data = model_to_dict(
        user,
        fields=['username', 'first_name', 'last_name', 'email', 'verify_email']
    )
    current_profile = Profile.objects.get(user=user)
    profile_data = model_to_dict(
        current_profile, fields=['birth', 'bio', 'avatar']
    )
    if request.method == "POST":
        user_form = EditUserForm(
            request.POST, initial=user_data, instance=user
        )
        profile_form = ProfileForm(
            request.POST, request.FILES,
            initial=profile_data, instance=current_profile
        )
        if profile_form.is_valid() and user_form.is_valid():
            profile_form.save()
            user_form.save()
            if any(data.has_changed() for data in [profile_form, user_form]):
                messages.success(request, "Your profile is updated!")
            else:
                messages.success(request, "No profile changes applied...")
            return HttpResponseRedirect(
                reverse("accounts:profile", kwargs={'user_id': user_id})
            )
    else:
        profile_form = ProfileForm(initial=profile_data)
        user_form = EditUserForm(initial=user_data)
    return render(
        request, 'accounts/edit_profile.html',
        {'profile_form': profile_form,
            'user_form': user_form,
            'username': user}
    )

Answer 1

The code for the assertRedirects method shows that the error message:

AssertionError: 301 != 200 : Couldn't retrieve redirection page '/accounts/sign_in'

is shown after the assertion method tries to follow the initial redirect to the login page. It expects the response status code to that second call to be whatever the target_status_code method parameter is set to (it defaults to 200 ).

You can stop the assertion error by either setting the target_status_code method parameter to 301 , or by setting the parameter fetch_redirect_response=False which will stop the attempt to follow the initial redirect.

Answer 2

While the 302 / 301 reasoning is explained in the notes, the reason the test is failing in the first place may be because your LOGIN_URL path is missing the trailing slash:

LOGIN_URL = '/account/login/'

Without a trailing slash, django will attempt to redirect due to the default setting of APPEND_SLASH .

This will result in the test failing for the reason described.