Looking for test driver to put a load on an asterisk server

Are there any tools available that I can use to simulate a set of clients in order to put a load on the server? I tried to use astertest but couldn’t get it to work (it looks like many others have the same problem). I’m primarily interested in driving SIP and IAX connections. If there is nothing available, I don’t mind writing some code myself, but would appreciate any advice others may have on how to approach this. Thanks.