add a transcoded test stream

vagrant-test/Vagrantfile

@@ -80,8 +80,10 @@ Vagrant.configure(API_VERSION) do |config|
     m.vm.provision "shell",
       inline: "sleep 3 && radioctl create-mount /stream.ogg"
 
-    # Start streaming.
+    # Start streaming, add a transcoded stream.
     m.vm.provision "shell", path: "start-source"
+    m.vm.provision "shell",
+      inline: "sleep 1 && radioctl create-transcoding-mount --bitrate=64 --codec=mp3 --source=/stream.ogg /stream.mp3"
   end
 
 end