array( 'email1@example.com', 'email2@example.com', 'email3@example.com', 'email4@example.com', 'email5@example.com', ), 'sub' => array( '-name-' => array( 'email1', '"email2"', 'email3\\', 'email4', 'email5', ), '-url-' => array( 'http://google.com', 'http://yahoo.com', 'http://hotmail.com', 'http://aol.com', 'http://facebook.com', ), ) ); $json = json_encode($complicated_header); $message = new Swift_Message(); $headers = $message->getHeaders(); $headers->addTextHeader('X-SMTPAPI', $json); $header = $headers->get('X-SMTPAPI'); $this->assertEqual('Swift_Mime_Headers_UnstructuredHeader', get_class($header)); $this->assertEqual($json, $header->getFieldBody()); } }