Install package from debian testing

[Godfrey]

I found the package unrar is in debian testing.  I checked all the
packages it depend on, and it's fine.  So I get it:

wget http://ftp.us.debian.org/debian/pool/non-free/u/unrar-nonfree/unrar-nonfree_3.3.6-2_i386.deb

Without include the testing in /etc/apt/sources.list, I just do:

sudo dpkg -i unrar-nonfree_3.3.6-2_i386.deb

My question, anybody see any problem here, is it the right thing to do, to
get a package from testing?