diff --git a/test/old/testdir/test_options.vim b/test/old/testdir/test_options.vim
index cbd1f74bd9..5a2d397b6e 100644
--- a/test/old/testdir/test_options.vim
+++ b/test/old/testdir/test_options.vim
@@ -1155,9 +1155,9 @@ func Test_backupskip()
       call writefile(['errors:'] + v:errors, 'Xtestout')
       qall
   [CODE]
-  call writefile(after, 'Xafter')
-  " let cmd = GetVimProg() . ' --not-a-term -S Xafter --cmd "set enc=utf8"'
-  let cmd = GetVimProg() . ' -S Xafter --cmd "set enc=utf8"'
+  call writefile(after, 'Xafter', 'D')
+  " let cmd = GetVimProg() . ' --clean --not-a-term -S Xafter --cmd "set enc=utf8"'
+  let cmd = GetVimProg() . ' --clean -S Xafter --cmd "set enc=utf8"'
 
   let saveenv = {}
   for var in ['TMPDIR', 'TMP', 'TEMP']
@@ -1165,9 +1165,9 @@ func Test_backupskip()
     call setenv(var, '/duplicate/path')
   endfor
 
-  " unset $HOME, so that it won't try to read init files
+  " set $HOME='', so that Vim won't try to read init files
   let saveenv['HOME'] = getenv("HOME")
-  call setenv('HOME', v:null)
+  call setenv('HOME', '')
   exe 'silent !' . cmd
   call assert_equal(['errors:'], readfile('Xtestout'))
 
@@ -1177,7 +1177,6 @@ func Test_backupskip()
   endfor
 
   call delete('Xtestout')
-  call delete('Xafter')
 
   " Duplicates should be filtered out (option has P_NODUP)
   let backupskip = &backupskip