patch 8.0.0388: filtering lines changes folds commit https://github.com/vim/vim/commit/1159b168dd94c1a25b4284c6544de385855df6f6 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Feb 28 21:53:56 2017 +0100 patch 8.0.0388: filtering lines changes folds Problem: filtering lines through "cat", without changing the line count, changes manual folds. Solution: Change how marks and folds are adjusted. (Matthew Malcomson, from neovim #6194.

" 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