I do not beleive that your license allows you to set up a test environment using the same license key. The Server license only allows for a single installation. In the same way that SQL, or the operating systems are not
licensed in such a way that you can build a duplicate install of the environment using the same keys. Technically speaking you are required to have a separate license for the test installation. With that said you should be able to spin up
a new CRM deployment on the same CRM server you have in production. CRM 2011 only comes with an enterprise key so you can go to the deployment manager and set up many separate unique instances of CRM on the same server.
Thanks,
Pierre Hulsebus - EHTC - CRM Practice Manager