diff --git a/src/test/perl/SimpleTee.pm b/src/test/perl/SimpleTee.pm
index 8d31a4013c..5da82d0f85 100644
--- a/src/test/perl/SimpleTee.pm
+++ b/src/test/perl/SimpleTee.pm
@@ -20,6 +20,7 @@ sub PRINT {
 	my $ok = 1;
 	for my $fh (@$self) {
 		print $fh @_ or $ok = 0;
+		$fh->flush or $ok = 0;
 	}
 	return $ok;
 }