patch 8.2.3423: Vim9: list += list creates a new list in :def function Commit: https://github.com/vim/vim/commit/07802044b90b2cbcc64b2dfe235f019d7c37589c Author: Bram Moolenaar <Bram@vim.org> Date: Thu Sep 9 23:01:14 2021 +0200 patch 8.2.3423: Vim9: list += list creates a new list in :def function Problem: Vim9: list += list creates a new list in :def function. Solution: Append to the existing list.

" 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