diff --git a/src/testdir/test_help.vim b/src/testdir/test_help.vim
index 219689b..966616c 100644
--- a/src/testdir/test_help.vim
+++ b/src/testdir/test_help.vim
@@ -74,6 +74,7 @@
 endfunc
 
 " Test for the :helptags command
+" NOTE: if you run tests as root this will fail.  Don't run tests as root!
 func Test_helptag_cmd()
   call mkdir('Xdir/a/doc', 'p')