commit https://github.com/vim/vim/commit/f1b512a0b62d0fa47ee9b2612556f375e1f22fc2 Author: Bram Moolenaar <Bram@vim.org> Date: Thu Sep 1 20:50:54 2016 +0200 patch 7.4.2302 Problem: Default interface versions for MS-Windows are outdated. Solution: Use Active Perl 5.24, Python 3.5.2. Could only make it work with Ruby 1.9.2.

" Common preparations for running tests.

" Make sure 'runtimepath' and 'packpath' does not include $HOME.
set rtp=$VIM/vimfiles,$VIMRUNTIME,$VIM/vimfiles/after
if has('packages')
  let &packpath = &rtp
endif

" Only when the +eval feature is present. 
if 1
  " Make sure $HOME does not get read or written.
  let $HOME = '/does/not/exist'
endif