commit https://github.com/vim/vim/commit/827b165b2aebad2cfe98cc6d5804c6c0fe8afd89 Author: Bram Moolenaar <Bram@vim.org> Date: Thu May 5 18:14:03 2016 +0200 patch 7.4.1819 Problem: Compiler warnings when sprintf() is a macro. Solution: Don't interrupt sprintf() with an #ifdef. (Michael Jarvis, closes https://github.com/vim/vim/issues/788)

" 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