add a test for dnserr api response

and also fix dnserr api response - should not contain additional info, but just "dnserr"

nsupdate/api/_tests/test_api.py

@@ -5,6 +5,7 @@ Tests for api package.
 from django.core.urlresolvers import reverse
 
 from nsupdate.main.dnstools import query_ns
+from nsupdate.main.models import Domain
 
 
 TEST_HOST = "test.nsupdate.info"
@@ -80,6 +81,16 @@ def test_nic_update_authorized(client):
     assert response.content.startswith('good ') or response.content.startswith('nochg ')
 
 
+def test_nic_update_authorized_ns_unavailable(client):
+    d = Domain.objects.get(domain=TEST_HOST)
+    d.available = False  # simulate DNS unavailability
+    d.save()
+    response = client.get(reverse('nic_update'),
+                          HTTP_AUTHORIZATION=make_basic_auth_header(TEST_HOST, TEST_SECRET))
+    assert response.status_code == 200
+    assert response.content == 'dnserr'
+
+
 def test_nic_update_authorized_myip(client):
     response = client.get(reverse('nic_update') + '?myip=4.3.2.1',
                           HTTP_AUTHORIZATION=make_basic_auth_header(TEST_HOST, TEST_SECRET))

nsupdate/api/views.py

@@ -311,4 +311,4 @@ def _update(host, hostname, ipaddr, ssl=False, logger=None):
         logger.error('%s - received update that resulted in a dns error [%s], ip: %s ssl: %r' % (
                      hostname, msg, ipaddr, ssl))
         host.register_server_fault()
-        return Response('dnserr %s' % msg)
+        return Response('dnserr')