commit https://github.com/vim/vim/commit/a260b87d9da17f605666630f18c1ed909c2b8bae Author: Bram Moolenaar <Bram@vim.org> Date: Fri Jan 15 20:48:22 2016 +0100 patch 7.4.1096 Problem: Need several lines to verify a command produces an error. Solution: Add assert_fails(). (suggested by Nikolay Pavlov) Make the quickfix alloc test actually work.

Tests for writefile()

STARTTEST
:source small.vim
:%delete _
:let f = tempname()
:call writefile(["over","written"], f, "b")
:call writefile(["hello","world"], f, "b")
:call writefile(["!", "good"], f, "a")
:call writefile(["morning"], f, "ab")
:call writefile(["", "vimmers"], f, "ab")
:bwipeout!
:$put =readfile(f)
:1 delete _
:w! test.out
:qa!
ENDTEST