diff --git a/tests/runtests.pl b/tests/runtests.pl
index 7911b76780..67e42b77e4 100755
--- a/tests/runtests.pl
+++ b/tests/runtests.pl
@@ -75,7 +75,8 @@ BEGIN {
 }
 
 use strict;
-use warnings;
+# Promote all warnings to fatal
+use warnings FATAL => 'all';
 use Cwd;
 use Digest::MD5 qw(md5);
 use MIME::Base64;