commit https://github.com/vim/vim/commit/f71d7b9ee5ceba75f70c30845332ddd728fd16c6 Author: Bram Moolenaar <Bram@vim.org> Date: Tue Aug 9 22:14:05 2016 +0200 patch 7.4.2189 Problem: Cannot detect encoding in a fifo. Solution: Extend the stdin way of detecting encoding to fifo. Add a test for detecting encoding on stdin and fifo. (Ken Takata)

func Test_empty_buffer()
  new
  insert
a
b
c
d
.
  call assert_equal(1, line("''"))
  bwipe!
endfunc