use strict;
use warnings;
use Test::More tests => 2;

my $corpus = q{foo<span class="Trsdu(0.3s) Fw(b) Fz(36px) Mb(-4px) D(ib)" data-reactid="33">bar};
my $lookfor = q{<span class="Trsdu(0.3s) Fw(b) Fz(36px) Mb(-4px) D(ib)" data-reactid="33">};

my $res = index ($corpus, $lookfor) + 1;
ok $res, 'Substring found';

$corpus = 'Something else';
$res = index ($corpus, $lookfor) + 1;
ok !$res, 'Substring not found';