patch 8.2.0397: delayed screen update when using undo from Insert mode Commit: https://github.com/vim/vim/commit/5715b3147bfc8ddfe905339f6fd224fd3a5a3ba1 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Mar 16 22:08:45 2020 +0100 patch 8.2.0397: delayed screen update when using undo from Insert mode Problem: Delayed screen update when using undo from Insert mode. Solution: Update w_topline and cursor shape before sleeping. (closes https://github.com/vim/vim/issues/5790)

function Test_Comparators()
  try
    let oldisident=&isident
    set isident+=#
    call assert_equal(1, 1 is#1)
  finally
    let &isident=oldisident
  endtry
endfunction