jsonify alert, needed for igwn-alert 0.2.2; fixes #433

bug fix in ceb4c768

gwcelery/tasks/igwn_alert.py

 """IGWN alert client."""
+import json
+
 from celery.utils.log import get_task_logger
 
 from ..igwn_alert.signals import igwn_alert_received
@@ -19,6 +21,7 @@ class _IGWNAlertDispatchHandler(DispatchHandler):
         return super().__call__(*keys, **kwargs)
 
     def process_args(self, topic, alert):
+        alert = json.loads(alert)
         # Determine GraceDB service URL
         try:
             try:

gwcelery/tests/test_tasks_igwn_alert.py

@@ -53,6 +53,8 @@ def test_handle_messages(mock_superevents_handle, mock_get_event,
     alert['object']['self'] = \
         alert['object']['self'].replace('gracedb.ligo.org', 'gracedb.invalid')
 
+    # dump back into string
+    alert = json.dumps(alert)
     # Run function under test
     igwn_alert.handler.dispatch(node, alert)
     mock_superevents_handle.assert_called_once()
@@ -70,7 +72,8 @@ def test_handle_messages_wrong_server(mock_superevents_handle,
     alert = json.loads(payload)
     alert['object']['self'] = \
         alert['object']['self'].replace('gracedb.ligo.org', 'gracedb2.invalid')
-
+    # dump back into string
+    alert = json.dumps(alert)
     # Run function under test
     caplog.set_level(logging.WARNING)
     igwn_alert.handler.dispatch(node, alert)
@@ -93,7 +96,8 @@ def test_handle_messages_no_self_link(mock_superevents_handle,
     # Manipulate alert content
     alert = json.loads(payload)
     del alert['object']['self']
-
+    # dump back into string
+    alert = json.dumps(alert)
     # Run function under test
     caplog.set_level(logging.ERROR)
     igwn_alert.handler.dispatch(node, alert)