Are there any online SAP RFC servers to test against?

Hi,
I am working on a Java client that will execute SAP RFC calls against a SAP server.

In the past we've been able to test at a client site, but this is no longer possible.

A long time ago, I found an online server that I was able to test basic RFC calls against, but that server no longer exists.

Are there any such servers out there where I can test basic RFC calls?
Just to see if I can send a message and get a response.

Thanks