tcltest package applicable for GUI apps?

Hello out there,
I wanted to use tcltest in conjunction with the development of a
fairly complex GUI app, but I have nothing but difficulties.
My situation is:
- I have a canvas with several objects
- The user can connect them, can select one or several of them and
move them around, etc.
Is it at all possible to use tcltest for simulating all kinds of user
interaction with such  a GUI?

I checked the tests of TK in the TK source tree but they concentrate
(understandebly) on testing the internal workings, like 'canvas
moveto' some rectangle and testing the resulting coordinates - nothing
like I was looking for.

Any idea, tip or link will be greatly appreciated
Helmut