runtests: consider warnings fatal and error on them

To help us detect and fix warnings in this script easier and faster.

Assisted-by: Jakob Hirsch
Ref: #10206
Closes #10208

diff --git a/tests/runtests.pl b/tests/runtests.pl
index 7911b767805e23552f79d2d305cdec368db36500..67e42b77e44b65f1d0ccd007d815f30be20ddfd6 100755 (executable)
--- 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;