public function testMail()
{
$app = $this->app;
$message = $this->getMockBuilder('Swift_Message')->disableOriginalConstructor()->getMock();
$app['mailer'] = $mailer = $this->getMockBuilder('Swift_Mailer')->disableOriginalConstructor()->getMock();
$mailer->expects($this->once())->method('send')->with($message);
$app->mail($message);
}