X11::GUITest is a Perl module for controlling applications through user-input emulation.
It lets you interact with applications running under X Window System — sending keystrokes, clicking mouse buttons, finding and manipulating windows, and more — including apps built with GTK+, Qt, Motif, and other toolkits on top of X11/Xlib.
If you're comparing GUI automation tools for X11, X11::GUITest is another option worth considering alongside xautomation and xdotool.
Note: This module...