diff --git a/tests/testutils.h b/tests/testutils.h
index bf5c701743d16743764242babad3fb0c5dad32dc..73c5f884c1136899ff9d1062bc980bb571873fd7 100644
--- a/tests/testutils.h
+++ b/tests/testutils.h
@@ -31,6 +31,10 @@
 # define EXIT_AM_SKIP 77 /* tell Automake we're skipping a test */
 # define EXIT_AM_HARDFAIL 99 /* tell Automake that the framework is broken */
 
+/* Work around lack of gnulib support for fprintf %z */
+# undef fprintf
+# define fprintf virFilePrintf
+
 extern char *progname;
 extern char *abs_srcdir;