"DejaGnu is a framework for testing other programs ... written in Expect ..." [L1 ] It's also an official GNU project of the FSF.
Unfortunately, DejaGnu's documentation online is not the full version. My suggestion is to install DejaGnu, and read the new one with the install-packet. If there's no such a thing, install src-packet. It will be located under file:///usr/share/dejagnu/html/book1.html .
Wish this could be helpful.
See also testing