coverage: Add test for REST requests to /json API unauthed.

zerver/lib/rest.py

@@ -104,6 +104,7 @@ def rest_dispatch(request, **kwargs):
             # If this looks like a request from a top-level page in a
             # browser, send the user to the login page
             if 'text/html' in request.META.get('HTTP_ACCEPT', ''):
+                # TODO: It seems like the `?next=` part is unlikely to be helpful
                 return HttpResponseRedirect('%s/?next=%s' % (settings.HOME_NOT_LOGGED_IN, request.path))
             # Ask for basic auth (email:apiKey)
             elif request.path.startswith("/api"):

zerver/tests/test_decorators.py

@@ -1023,3 +1023,10 @@ class RestAPITest(ZulipTestCase):
         result = self.client_options('/json/streams/15')
         self.assertEqual(result.status_code, 204)
         self.assertEqual(str(result['Allow']), 'DELETE, PATCH')
+
+    def test_http_accept_redirect(self):
+        # type: () -> None
+        result = self.client_get('/json/users',
+                                 HTTP_ACCEPT='text/html')
+        self.assertEqual(result.status_code, 302)
+        self.assertTrue(result["Location"].endswith("/login/?next=/json/users"))