diff --git a/src/testdir/test_gui.vim b/src/testdir/test_gui.vim
index d95d991..fbea706 100644
--- a/src/testdir/test_gui.vim
+++ b/src/testdir/test_gui.vim
@@ -10,7 +10,11 @@
     set guifont=Courier\ 10\ Pitch/8/-1/5/50/0/0/0/0/0
   endif
 
-  " Gnome insists on creating $HOME/.gnome2/..
+  " Gnome insists on creating $HOME/.gnome2/, and we're going to abide by
+  " that, taking care to have the font cache work normally.
+  if $XDG_CACHE_HOME == ''
+    let $XDG_CACHE_HOME = g:tester_HOME . '/.cache'
+  endif
   call mkdir('Xhome')
   let $HOME = fnamemodify('Xhome', ':p')
 endfunc