piuparts is a tool for testing that .deb packages can be installed, upgraded, and removed without problems. The name, a variant of something suggested by Tollef Fog Heen, is short for "package installation, upgrading and removal testing suite".
It does this by creating a minimal Debian installation in a chroot, and installing, upgrading, and removing packages in that environment, and comparing the state of the directory tree before and after. piuparts reports any files that have been added, removed, or modified during this process.
piuparts is meant as a quality assurance tool for people who create .deb packages to test them before they upload them to the Debian package archive.