How to duplicate a website in a subdomain.

Hi,
I would like to establish a testing environment for the website http://www.demosandpolis.com

For that reason, I created this subdomain:
http://www.pruebas.demosandpolis.com

I would like to the whole current customization from the original site to the subdomain. Is this possible? and if so, how I have to do it?

Thank you very much for your help and support,

Virginia