[damned-lies] Fixes #92 - Repaired redirection after login

[Claude Paroz <claudep src gnome org>]

commit d1d6e1afb43d34cea8ed2a34bebc06326381f57f
Author: Claude Paroz <claude 2xlibre net>
Date:   Sat Aug 11 14:43:54 2018 +0200

    Fixes #92 - Repaired redirection after login
    
    Regression in d44360a3b986a6316c2e538124496c1e54d42abb.

 common/views.py | 7 +++++++
 people/tests.py | 6 ++++++
 2 files changed, 13 insertions(+)
---
diff --git a/common/views.py b/common/views.py
index 5e33f06a..00f2262d 100644
--- a/common/views.py
+++ b/common/views.py
@@ -44,6 +44,13 @@ def about(request):
 
 class LoginView(AuthLoginView):
     form_class = LoginForm
+    redirect_field_name = 'referer'
+
+    def get_context_data(self, **kwargs):
+        context = super().get_context_data(**kwargs)
+        if not context['referer']:
+            context['referer'] = self.request.META.get('HTTP_REFERER', '')
+        return context
 
     def form_valid(self, form):
         response = super().form_valid(form)
diff --git a/people/tests.py b/people/tests.py
index 32b34967..6e15de5e 100644
--- a/people/tests.py
+++ b/people/tests.py
@@ -58,6 +58,12 @@ class PeopleTestCase(TestCase):
 
     def test_login_message(self):
         self.pn = self._create_person()
+        response = self.client.get(reverse('login'), HTTP_REFERER='http://foo/bar')
+        self.assertContains(
+            response,
+            '<input type="hidden" name="referer" value="http://foo/bar";>',
+            html=True
+        )
         response = self.client.post(
             reverse('login'), data={'username': 'jn', 'password': 'password'}, follow=True
         )