public function testTransportFilters()
 {
     $transport = 'transport_test';
     $message = new \stdClass();
     /* @var MailRenderedInterface|\PHPUnit_Framework_MockObject_MockObject $mailRendered */
     $mailRendered = $this->getMockBuilder(MailRenderedInterface::class)->getMock();
     /* @var FilterPreSendEvent|\PHPUnit_Framework_MockObject_MockObject $event */
     $event = $this->getMockBuilder(FilterPreSendEvent::class)->disableOriginalConstructor()->getMock();
     $event->expects($this->atLeastOnce())->method('getTransport')->will($this->returnValue($transport));
     $event->expects($this->atLeastOnce())->method('getMessage')->will($this->returnValue($message));
     $event->expects($this->atLeastOnce())->method('getMailRendered')->will($this->returnValue($mailRendered));
     /* @var TransportFilterInterface|\PHPUnit_Framework_MockObject_MockObject $transportFilter */
     $transportFilter = $this->getMockBuilder(TransportFilterInterface::class)->getMock();
     $transportFilter->expects($this->once())->method('supports')->with($transport, $message, $mailRendered)->will($this->returnValue(true));
     $transportFilter->expects($this->once())->method('filter')->with($transport, $message, $mailRendered);
     $this->registry->expects($this->once())->method('getTransportFilters')->will($this->returnValue(array($transportFilter)));
     $this->listener->onPreSend($event);
 }