add registration email template test

booking.emails.inc

@@ -47,6 +47,7 @@ function _booking_registration_email($nid, $balance_payment, $manual = false) {
 			'module' => 'booking',
 			'key' => 'registration_mail',
 			'body' => _booking_registration_email_generate($node, $waiting_list, $balance_payment, $manual),
+			'subject' => $subject,
 	));
 	watchdog('booking_debug', "<pre>HTML body themed\n@info</pre>", array('@info' => print_r($html_body, true)));
 	$params['body'] = $html_body;