You would probably be better doing any testing on a locally installed web server (on your own desktop).
I already have kiwitrees running on my desktop computer (iMac with Mac OS X running PHP 5.5 on an Apache web server), and also on my personal site (loveluck.net/kiwitrees), hosted by OVH. On free.fr I’ve been managing, with a fellow researcher, a web site for an (unofficial) one-name study of the Lovelock surname. Up to now we’ve been using an old version of PhpGedView (4.1.7) running on PHP 5.1.3, which is increasingly problematic, given the lack of support. When I discovered that Free were planning to support PHP 5.6 I thought it would be an opportunity to move to Kiwitreees, but it seems that it isn’t that simple! I’m going to recommend to my fellow researcher that we move to another web hosting service (maybe kiwitrees?))