Fix API response when there are no actions to return

mygpo/api/advanced/__init__.py

@@ -171,8 +171,12 @@ def get_episode_changes(user, podcast, device, since, until, aggregated, version
     if aggregated:
         actions = list(dict( (a['episode'], a) for a in actions ).values())
 
-    timestamp = history[-1].timestamp
-    return {'actions': actions, 'timestamp': get_timestamp(timestamp)}
+    if history:
+        ts = get_timestamp(history[-1].timestamp)
+    else:
+        ts = get_timestamp(until)
+
+    return {'actions': actions, 'timestamp': ts}
 
 
 def episode_action_json(history, user):

mygpo/api/tests.py

@@ -267,3 +267,28 @@ def test_limit_actions(self):
             get_timestamp(timestamps[9]),
             response_obj['timestamp']
         )
+
+
+    def test_no_actions(self):
+        """ Test when there are no actions to return """
+
+        t1 = get_timestamp(datetime.utcnow())
+
+        url = reverse(episodes, kwargs={
+            'version': '2',
+            'username': self.user.username,
+        })
+        response = self.client.get(url, {'since': '0'}, **self.extra)
+        self.assertEqual(response.status_code, 200, response.content)
+        response_obj = json.loads(response.content.decode('utf-8'))
+        actions = response_obj['actions']
+
+        # 10 actions should be returned
+        self.assertEqual(len(actions), 0)
+
+        returned = response_obj['timestamp']
+        t2 = get_timestamp(datetime.utcnow())
+        # the `timestamp` field in the response should be the timestamp of the
+        # last returned action
+        self.assertGreaterEqual(returned, t1)
+        self.assertGreaterEqual(t2, returned)