If you have implemented Music on Hold on your asterisk box, you may want to listen to it, to know if it is working as you want, of course you can call to your IVR number and wait for the music on hold, but it is better if you create an extension specially designed to hear to music on hold.

This is how to do it, in the extensions.conf file add these lines in the context your extension is.

exten => 1000,1,Answer 
exten => 1000,2,MusicOnHold() 

Now each time you dial 1000, you will be redirected to music on hold, and you will be able test how it is working.