Hope my word did not confuse you about updates/upgrades. It is my personal practice of not running system wide update/upgrade and update/upgrade packages for what I want.
Since you are running VL in vbox, you can play with it to get more familiar. But running a system wide update/upgrade with testing repo enable is highly not recommended. Only install/upgrade packages that you want from the testing repo and disable it afterward.
VL does not provide auto update/upgrade function like Ubuntu, so for important update/upgrade will be announce in the forum.