arn extractor returns "" instead of None

Author: michael-zhao459

datadog_lambda/wrapper.py

@@ -384,11 +384,11 @@ def carrier_get(key):
 
 def extract_source_arn(event, event_source):
     if event_source.equals(EventTypes.SQS) or event_source.equals(EventTypes.KINESIS):
-        return event.get("Records", [{}])[0].get("eventSourceARN")
+        return event.get("Records", [{}])[0].get("eventSourceARN", "")
     elif event_source.equals(EventTypes.SNS):
-        return event.get("Records", [{}])[0].get("Sns", {}).get("TopicArn")
+        return event.get("Records", [{}])[0].get("Sns", {}).get("TopicArn", "")
     else:
-        return None
+        return ""
 
 
 datadog_lambda_wrapper = _LambdaDecorator

tests/test_wrapper.py

@@ -978,4 +978,4 @@ def test_extract_source_arn_other_event(self):
         )()
 
         result = wrapper.extract_source_arn(other_event, event_source)
-        self.assertIsNone(result)
+        self.assertEqual(result, "")