This testsuite is NOT SECURE: it will temporarily change your passwords file
with known passwords.
You should run it on a chroot, or on a secured dedicated system.
To test a Debian system:
$ mkdir sid-chroot
$ sudo debootstrap sid sid-chroot/ http://ftp.fr.debian.org/debian/
edit or copy a sources.list
$ sudo cp /etc/apt/sources.list sid-chroot/etc/apt/
edit or copy a resolv.conf
$ sudo cp /etc/resolv.conf sid-chroot/etc/
$ su - root -c "chroot sid-chroot/ /bin/bash"
# mount -t proc proc /proc
# mount -t devpts devpts /dev/pts
# aptitude update
# aptitude install expect
# cd /dev ; mknod --mode=666 /dev/ptmx c 5 2