Modifying the routing to persist the topic name into the envelope so …

…it will be part of the envelope persisted in the message store. Closes GH-1100

src/Transports/RabbitMQ/Wolverine.RabbitMQ.Tests/send_by_topics.cs

@@ -8,6 +8,7 @@
 using Wolverine.ComplianceTests.Compliance;
 using Wolverine.Attributes;
 using Wolverine.Marten;
+using Wolverine.Runtime.Routing;
 using Wolverine.Tracking;
 using Xunit;
 
@@ -70,6 +71,20 @@ public void Dispose()
         theThirdReceiver?.Dispose();
     }
 
+    [Fact]
+    public void topic_name_needs_to_be_set_on_envelope_as_part_of_routing()
+    {
+        // Really a global Wolverine behavior test, but using Rabbit MQ as the subject
+        // Caused by https://github.com/JasperFx/wolverine/issues/1100
+        var runtime = theSender.GetRuntime();
+
+        var router = runtime.RoutingFor(typeof(PurpleMessage));
+        var envelopes = router.RouteForPublish(new PurpleMessage(), null);
+
+        var envelope = envelopes.Single();
+        envelope.TopicName.ShouldBe(TopicRouting.DetermineTopicName(typeof(PurpleMessage)));
+    }
+
     internal async Task send_by_topic_sample()
     {
         #region sample_send_to_topic

src/Wolverine/Runtime/Routing/MessageRoute.cs

@@ -85,6 +85,12 @@ public Envelope CreateForSending(object message, DeliveryOptions? options, ISend
         // Delivery options win
         options?.Override(envelope);
 
+        // Will need the topic persisted, see https://github.com/JasperFx/wolverine/issues/1100
+        if (Sender.Endpoint.RoutingType == RoutingMode.ByTopic && envelope.TopicName.IsEmpty())
+        {
+            envelope.TopicName = TopicRouting.DetermineTopicName(envelope);
+        }
+
         if (envelope.IsScheduledForLater(DateTimeOffset.UtcNow))
         {
             if (IsLocal)