diff --git a/input/tests/views.py b/input/tests/views.py
index 5109466..aee69c9 100644
--- a/input/tests/views.py
+++ b/input/tests/views.py
@@ -28,6 +28,9 @@ class AnonymousViewTestCase(TestCase):
 
         request(self, 'extern', expected_url=url, data={'url': url})
 
+    def test_extern_invalid_url(self):
+        request(self, 'extern', data={'url': 'https://domain.not/allowed/to/be/redirected/'})
+
     @classmethod
     def get_step_data(cls, choice, **data):
         return {