This is a test dependency of the upcoming AdaID port.  There are existing
ports that also could use Aunit but they currently work around or skip
testing options.

===
AUnit is a set of Ada packages based on the xUnit family of unit test
frameworks. It is intended as a developer's tool to facilitate confident
writing and evolution of Ada software. It is purposely lightweight, as
one of its main goals is to make it easy to develop and run unit tests,
rather than to generate artifacts for process management. The framework
supports easy composition of sets of unit tests to provide flexibility
in determining what tests to run for a given purpose.