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/runtest.vim b/src/testdir/runtest.vim
index 0cf5000..4d75af3 100644
--- a/src/testdir/runtest.vim
+++ b/src/testdir/runtest.vim
@@ -55,6 +55,9 @@
 " Always use forward slashes.
 set shellslash
 
+" Make sure $HOME does not get read or written.
+let $HOME = '/does/not/exist'
+
 let s:srcdir = expand('%:p:h:h')
 
 " Support function: get the alloc ID by name.
@@ -141,7 +144,6 @@
     call extend(s:errors, v:errors)
     let v:errors = []
   endif
-
 endfor
 
 if s:fail == 0
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
diff --git a/src/testdir/test_viminfo.vim b/src/testdir/test_viminfo.vim
index 3efe75e..a979ab9 100644
--- a/src/testdir/test_viminfo.vim
+++ b/src/testdir/test_viminfo.vim
@@ -36,7 +36,7 @@
   " store a really long list, so line wrapping will occur in viminfo file
   let test_list = range(1,100)
   let g:MY_GLOBAL_LIST = test_list
-  set viminfo='100,<50,s10,h,!
+  set viminfo='100,<50,s10,h,!,nviminfo
   wv! Xviminfo
   unlet g:MY_GLOBAL_DICT
   unlet g:MY_GLOBAL_LIST
diff --git a/src/version.c b/src/version.c
index 1b34431..f2976cb 100644
--- a/src/version.c
+++ b/src/version.c
@@ -749,6 +749,8 @@
 static int included_patches[] =
 {   /* Add new patch number below this line */
 /**/
+    1686,
+/**/
     1685,
 /**/
     1684,