[docs] [issue13402] Document absoluteness of sys.executable

STINNER Victor <victor.stinner@haypocalc.com> added the comment:

You could also add a test to test_sys ensuring that sys.executable is always executable.

And that sys.executable is absolute? sys.executable is an empty string if sys.argv[0] has been changed and Python is unable to retrieve the real path to the Python executable. See the issue #7774. The fact that sys.executable can be empty should be documented. ---------- _______________________________________ Python tracker <report@bugs.python.org> <http://bugs.python.org/issue13402> _______________________________________