[development] Setting up test environment

Okay I want to set up a place to test all my servers on 4.7. so I grabbed the latest from HEAD, copied my databases (ie if the db was example, I now also have one called example4_7). Then I created a Virtual Host called test.example.com , that is set to read the code from HEAD. Now here's where I'm not so sure. Should I now go with an upgrade? (http://test.example.org/update.php) or should I act as if its a new install (I guess technically it is) Since I want to use all the data from my old install I'm leaning torward, I should be doing an update but I'm concerned that I have modules set up that aren't ready for 4.7 yet. so advise....?