patch 8.0.1770: assert functions don't return anything commit https://github.com/vim/vim/commit/65a5464985f980d2bbbf4e14d39d416dce065ec7 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Apr 28 16:56:53 2018 +0200 patch 8.0.1770: assert functions don't return anything Problem: Assert functions don't return anything. Solution: Return non-zero when the assertion fails.

" 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