Give a work-queue stream its one consumer, drop-only dead letters (issue 1178)

internal/broker/modstream_work_queue_test.go

@@ -36,3 +36,21 @@ func TestANonWorkQueueStreamStillDropsItsOldest(t *testing.T) {
 		t.Fatalf("composed as %+v; want limits retention, never discarding new, no duplicate window", s)
 	}
 }
+
+// 1178/AC1: the process a work-queue stream's bus.queues names gets exactly one durable consumer,
+// <node>_<module>_<process id>, with the stream's declared max-deliver — composed even though mesh-mail's
+// sender otherwise consumes and watches nothing of its own, which alone would give ConsumerFor nothing
+// needed. Explicit acknowledgement is EnsureConsumer's own rule for every consumer it makes (jetstream.go),
+// so it is not re-asserted here.
+func TestTheOneProcessAWorkQueuesBusNamesGetsItsOwnConsumer(t *testing.T) {
+	sender := Principal{Kind: KindModule, Node: "novox", Module: "mesh-mail", PasswordHash: "x",
+		Queues: []QueueOwner{{Process: "send", Stream: "MAIL_SENDS", MaxDeliver: 5}}}
+	got := ConsumersOf([]Principal{sender})
+	if len(got) != 1 {
+		t.Fatalf("mesh-mail's consumers: %+v", got)
+	}
+	c := got[0].Consumer
+	if c.Name != "novox_mesh-mail_send" || c.Stream != "MAIL_SENDS" || c.MaxDeliver != 5 {
+		t.Fatalf("the queue's consumer: %+v", c)
+	}
+}