Does Unstable become Testing?

["Thomas H. George" <tomgeorge@spininternet.com>]

When Sarge is released does Unstable suddenly become Testing or is 
Testing simply empty until new programs gradually migrate from Unstable 
to Testing?

I have been regularly doing dist-upgrade to Testing regularly for over a 
year and have been very happy with the results.  No significant 
instability problems and new programs - for example, gwc - are 
available.  After Sarge is released if Testing is just empty until 
programs are ready to be moved from Unstable to Testing I want to 
continue to upgrade.  Is this reasonable?

Tom George