patch 8.1.0513: no error for set diffopt+=algorithm: commit https://github.com/vim/vim/commit/d0721058f494143186f66a60151c9634031a8c96 Author: Bram Moolenaar <Bram@vim.org> Date: Mon Nov 5 21:21:33 2018 +0100 patch 8.1.0513: no error for set diffopt+=algorithm: Problem: No error for set diffopt+=algorithm:. Solution: Check for missing argument. (Hirohito Higashi, closes https://github.com/vim/vim/issues/3598)

" Test 'autochdir' behavior

if !exists("+autochdir")
  finish
endif

func Test_set_filename()
  let cwd = getcwd()
  call test_autochdir()
  set acd
  new
  w samples/Xtest
  call assert_equal("Xtest", expand('%'))
  call assert_equal("samples", substitute(getcwd(), '.*/\(\k*\)', '\1', ''))
  bwipe!
  set noacd
  exe 'cd ' . cwd
  call delete('samples/Xtest')
endfunc