patch 8.2.0077: settagstack() cannot truncate at current index Commit: https://github.com/vim/vim/commit/271fa08a35b8d320d3a40db4ddae83b698fdd4fb Author: Bram Moolenaar <Bram@vim.org> Date: Thu Jan 2 14:02:16 2020 +0100 patch 8.2.0077: settagstack() cannot truncate at current index Problem: settagstack() cannot truncate at current index. Solution: Add the "t" action. (Yegappan Lakshmanan, closes https://github.com/vim/vim/issues/5417)

" 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