patch 8.0.0655: not easy to make sure a function does not exist commit https://github.com/vim/vim/commit/d6abcd154cdc6a8dd4b7c6ccad37617ea8a1b4aa Author: Bram Moolenaar <Bram@vim.org> Date: Thu Jun 22 19:15:24 2017 +0200 patch 8.0.0655: not easy to make sure a function does not exist Problem: Not easy to make sure a function does not exist. Solution: Add ! as an optional argument to :delfunc.

" Settings for test script execution
" Always use "COMMAND.COM", don't use the value of "$SHELL".
set shell=c:\COMMAND.COM shellquote= shellxquote= shellcmdflag=/c shellredir=>
" This is used only when the +eval feature is available.
if executable("cmd.exe")
   set shell=cmd.exe
endif

source setup.vim