Update integration tests error code for invalid fid target

Author: yvonnep165

firebase_admin/_messaging_utils.py

@@ -519,7 +519,8 @@ def __init__(self, message, cause=None, http_response=None):
 class UnregisteredError(exceptions.NotFoundError):
     """App instance was unregistered from FCM.
 
-    This usually means that the token used is no longer valid and a new one must be used."""
+    This usually means that the registration token or installation ID (FID) used
+    is no longer valid and a new one must be used."""
 
     def __init__(self, message, cause=None, http_response=None):
         exceptions.NotFoundError.__init__(self, message, cause, http_response)

integration/test_messaging.py

@@ -92,7 +92,7 @@ def test_send_invalid_fid():
         fid='not-a-fid',
         notification=messaging.Notification('test-title', 'test-body')
     )
-    with pytest.raises(exceptions.InvalidArgumentError):
+    with pytest.raises(messaging.UnregisteredError):
         messaging.send(msg, dry_run=True)
 
 def test_send_each():
@@ -169,7 +169,7 @@ def test_send_each_for_multicast_fids():
     assert len(batch_response.responses) == 2
     for response in batch_response.responses:
         assert response.success is False
-        assert response.exception is not None
+        assert isinstance(response.exception, messaging.UnregisteredError)
         assert response.message_id is None
 
 def test_subscribe():