How to prohibit user to change OS window focus/type keys for several seconds on Linux

Question

I write automated tests for a website. One of the tests needs to press Ctrl+S and type some letters to save a webpage including CSS/JS. The test should require Firefox to have window focus for those several seconds to be able to type the filename and click "Save" (currently XDoTool is used for pressing keys and clicking the mouse).

Sometimes I run the tests on my computer. I don't want to occasionally type something or change the window focus while the page is being saved, so I want to prohibit changing focus for those several seconds when those mouse clicks/key presses are running.

It's not possible to do it at the Webdriver level (a tool that I use for controlling the browser), so I think I should do it at the OS level. Can I prohibit the user from changing window focus or typing anything for a period of time? It may look like:

prohibit user from typing keys/change window focus
save page
allow user to type/change window focus

Answer 1

I guess that another way to achieve the desired effect would be to run Firefox and your automated tests on a nested X server (xf86-video-nested/Xephyr/Xnest).

$ Xnest :1
$ export DISPLAY=:1.0
$ firefox http://something/to/test &
$ your-test-script

Since the nested X server has it's own idea of the focused window, moving the focus on your desktop shouldn't affect it.

(If you don't actually need to see the test progressing, you could use a dummy X server (xf86-video-dummy/Xvfb/Xfake) instead)