As others have mentioned, though you might not have seen the replies if
you weren't CC'd on them, you could change from 'testing' to 'squeeze'
now as they are currently the same thing. Then when squeeze goes stable
you could change to 'stable', this will allow you to track the stable
distribution and it will upgrade to the next stable 'wheezy', when that
is released.
I wouldn't suggest that as it can deal to unexpected surprises.
Of course, you can do as you see, but in order to track Stable, I always
suggest doing it by tracking codename changes, so stay with, say, squeeze
till you know wheezy has come Stable and you are ready for the upgrade, then
change the codename on your sources and do it.