Testar o swiftmail

gistfile1.php

<?php
require_once 'vendor/swiftmailer/swiftmailer/lib/swift_required.php';

$transport = Swift_SmtpTransport::newInstance('smtp.host.com', 25, 'tls')
->setUsername('')
->setPassword('');

$mailer = Swift_Mailer::newInstance($transport);

$message = Swift_Message::newInstance('Informação')
->setFrom("no-reply@.com")
->setTo("to@.com")
->setBody(file_get_contents('app/upload/mail.html'), 'text/html');

$mailer->send($message);