commit https://github.com/vim/vim/commit/18dfb4404a618c52ee7138630a2381aed4d66eaf Author: Bram Moolenaar <Bram@vim.org> Date: Tue May 31 22:31:23 2016 +0200 patch 7.4.1862 Problem: string() with repeated argument does not give a result usable by eval(). Solution: Refactor echo_striong and tv2string(), moving the common part to echo_string_core(). (Ken Takata)

" Tests for :undo

func Test_ex_undo()
  new ex-undo
  setlocal ul=10
  exe "normal ione\n\<Esc>"
  setlocal ul=10
  exe "normal itwo\n\<Esc>"
  setlocal ul=10
  exe "normal ithree\n\<Esc>"
  call assert_equal(4, line('$'))
  undo
  call assert_equal(3, line('$'))
  undo 1
  call assert_equal(2, line('$'))
  undo 0
  call assert_equal(1, line('$'))
  quit!
endfunc