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 "sh", don't use the value of "$SHELL".
set shell=sh

" Only when the +eval feature is present. 
if 1
  " While some tests overwrite $HOME to prevent them from polluting user files,
  " we need to remember the original value so that we can tell external systems
  " where to ask about their own user settings.
  let g:tester_HOME = $HOME
endif

source setup.vim