Problems with Tkinter libraries dependencies in a codespace on Ubuntu 22.04.1 (linux)

Issue with Testing tkinter in a Headless Environment

What I Am Trying to Do

I am trying to test if tkinter is installed and working by running the following command in the terminal:

python3 -m tkinter

I've installed tkinter dependencies (e.g., sudo apt-get install python3-tk) and verified your Python version is 3.1

Error Message When I run the command, I get the following error:

  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/home/codespace/.python/current/lib/python3.12/tkinter/__main__.py", line 7, in <module>
    main()
  File "/home/codespace/.python/current/lib/python3.12/tkinter/__init__.py", line 4633, in _test
    root = Tk()
           ^^^^
  File "/home/codespace/.python/current/lib/python3.12/tkinter/__init__.py", line 2340, in __init__
    self.tk = _tkinter.create(screenName, baseName, className, interactive, wantobjects, useTk, sync, use)
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
_tkinter.TclError: no display name and no $DISPLAY environment variable

Headless environment doesn't run X11 (or Wayland) so it can't display GUI programs - and this makes your problem.

You may try to use Xvfb to create virtual X11.

apt install xvfb

and later

xvfb-run python3 -m tkinter

Because it doesn't display tkinter's window so it can't be closed with clicking button [X] on window but it can be killed with Ctrl+C. Or you may kill it using other console. It is simpler with pkill instead of kill

pkill xvfb

Tested on Linux Mint 22 based on Ubuntu 22.04

---

Useful for test

xvfb-run python3 -c "import os;print(os.environ.get('DISPLAY'))"

Result: :99

---

Python has modules to work with Xvfb - like xvfbwrapper, pytest-xvfb

---

This is good for automatic tests but not for interactive work.

For automatic tests you may use pyautogui, pynput to control keyboard and mouse with code.

There is also module keyboard and mouse but keyboard needs sudo to run it as root.

You can take screenshots with pyautogui or python-mss (but I didn't test it in xvfb)