gistfile1.diff

diff --git a/lib/ruote-amqp/participant.rb b/lib/ruote-amqp/participant.rb
index 25bf604..40456fd 100644
--- a/lib/ruote-amqp/participant.rb
+++ b/lib/ruote-amqp/participant.rb
@@ -158,7 +158,9 @@ module RuoteAMQP
 
       else
 
-        q.publish(encode_workitem(workitem), opts)
+        wi = encode_workitem(workitem)
+        raise ArgumentError, "encoded workitem is nil" if wi.nil?
+        q.publish(wi, opts)
       end
 
       reply_to_engine(workitem) if forget