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 Date: Thu Sep 1 20:50:54 2016 +0200 patch 7.4.2302 Problem: Default interface versions for MS-Windows are outdated.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.

" Test for joining lines.

func Test_join_with_count()
  new
  call setline(1, ['one', 'two', 'three', 'four'])
  normal J
  call assert_equal('one two', getline(1))
  %del
  call setline(1, ['one', 'two', 'three', 'four'])
  normal 10J
  call assert_equal('one two three four', getline(1))
  quit!
endfunc