Just out of curiosity: Does that also mean, that a user running
'apt-get
source <package>' may not receive the package version shipped in
testing, but one used by an other package?
If there is both a source and binary named <package> or requests
source
for a binary package, one should get the right version:
+---
| $ apt-get -t testing source grub2
| [...]
| Need to get 5079 kB of source archives.
| Get:1 http://ftp.de.debian.org/debian/ testing/main grub2
1.99-27+deb7u1 (dsc) [3729 B]
| [...]
+---
Otherwise I think one gets the highest version of the source package.