It is our intention to have the Test World up 24/7 however it has been brought down at the end of office hours here to address Stability issues which the devs are diligently working to resolve.
As I said it is our intention to have a stable server up 24/7, barring patches being applied and stability problems that may occur. However once that becomes the case I am sure it will go through the normal maintenance cycle the live server currently experience.
