commit https://github.com/vim/vim/commit/e8aee7dcf9b12becff86e8ce1783a86801c5f9f6 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Apr 26 21:39:13 2016 +0200 patch 7.4.1793 Problem: Some character classes may differ between systems. On OS/X the regexp test fails. Solution: Make this less dependent on the system. (idea by Kazunobu Kuriyama)

" Test feedkeys() function.

func Test_feedkeys_x_with_empty_string()
  new
  call feedkeys("ifoo\<Esc>")
  call assert_equal('', getline('.'))
  call feedkeys('', 'x')
  call assert_equal('foo', getline('.'))

  " check it goes back to normal mode immediately.
  call feedkeys('i', 'x')
  call assert_equal('foo', getline('.'))
  quit!
endfunc