patch 7.4.1686
Problem:    When running tests $HOME/.viminfo is written. (James McCoy)
Solution:   Add 'nviminfo' to the 'viminfo' option. (closes #722)
diff --git a/src/testdir/test_backspace_opt.vim b/src/testdir/test_backspace_opt.vim
index f80e831..7fbba96 100644
--- a/src/testdir/test_backspace_opt.vim
+++ b/src/testdir/test_backspace_opt.vim
@@ -53,7 +53,7 @@
   " Cleared when 'compatible' is set
   set compatible
   call assert_equal('', &backspace)
-  set nocompatible
+  set nocompatible viminfo+=nviminfo
 endfunc
 
 " vim: tabstop=2 shiftwidth=0 expandtab