views: keep next_url on password reset (#69537)

It was already working in the regular case, but not if no account
matches the given email.

src/authentic2/forms/passwords.py

@@ -127,7 +127,12 @@ class PasswordResetForm(HoneypotForm):
             logger.info('password reset request for "%s", no user found', email)
             if getattr(settings, 'REGISTRATION_OPEN', True):
                 ctx = {
-                    'registration_url': utils_misc.make_url('registration_register', absolute=True),
+                    'registration_url': utils_misc.make_url(
+                        'registration_register',
+                        absolute=True,
+                        next_url=self.cleaned_data.get('next_url'),
+                        sign_next_url=True,
+                    ),
                 }
             else:
                 ctx = {}

tests/test_password_reset.py

@@ -167,8 +167,7 @@ def test_old_url_redirect(app):
 )
 def test_send_password_reset_email_no_account(app, db, mailoutbox, settings, registration_open):
     settings.REGISTRATION_OPEN = registration_open
-    url = reverse('password_reset')
-    resp = app.get(url, status=200)
+    resp = app.get('/password/reset/?next=/whatever/', status=200)
     resp.form.set('email', 'test@entrouvert.com')
     resp = resp.form.submit()
 
@@ -178,6 +177,8 @@ def test_send_password_reset_email_no_account(app, db, mailoutbox, settings, reg
         assert 'no account was found associated with this address' in body
         if settings.REGISTRATION_OPEN:
             assert 'http://testserver/register/' in body
+            # check next_url was preserved
+            assert 'next=/whatever/' in body
         else:
             assert 'http://testserver/register/' not in body