use open ':std', ':encoding(utf8)';
use utf8;

use Test::More tests => 1;

my $s = '2♥ 5♥ 7♦ 8♣ 9♠';

ok utf8::is_utf8($s), "String '$s' is utf8 even if 'use utf8;' goes after 'use open ':std', ':encoding(utf8)'";