Indeed, it would be easier to install and test it with an application so you wouldn't have to install a whole desktop environment. The thing is, Telepathy is designed for desktop integration rather than app integration which is why you see it in Hildon and KDE but not Pidgin.

Pidgin on the other hand, doesn't support Telepathy plugins but it does provide libpurple which is like the equivalent of Telepathy for apps. Interestingly enough, there is a libpurple plugin for Telepathy which allows you to use Pidgin plugins. So the other route you could take would be to develop a Ring/Jami plugin for Pidgin and then run that under Telepathy using the libpurple plugin.