public static function suite()
 {
     $suite = new PHPUnit_Framework_TestSuite('Zend Framework - Zend_Mail');
     $suite->addTest(Zend_Mail_Header_AllTests::suite());
     $suite->addTestSuite('Zend_Mail_MailTest');
     $suite->addTestSuite('Zend_Mail_MessageTest');
     $suite->addTestSuite('Zend_Mail_InterfaceTest');
     $suite->addTestSuite('Zend_Mail_MboxTest');
     $suite->addTestSuite('Zend_Mail_MboxMessageOldTest');
     $suite->addTestSuite('Zend_Mail_MboxFolderTest');
     if (defined('TESTS_ZEND_MAIL_POP3_ENABLED') && constant('TESTS_ZEND_MAIL_POP3_ENABLED') == true) {
         $suite->addTestSuite('Zend_Mail_Pop3Test');
     }
     if (defined('TESTS_ZEND_MAIL_IMAP_ENABLED') && constant('TESTS_ZEND_MAIL_IMAP_ENABLED') == true) {
         $suite->addTestSuite('Zend_Mail_ImapTest');
     }
     if (defined('TESTS_ZEND_MAIL_MAILDIR_ENABLED') && constant('TESTS_ZEND_MAIL_MAILDIR_ENABLED')) {
         $suite->addTestSuite('Zend_Mail_MaildirTest');
         $suite->addTestSuite('Zend_Mail_MaildirMessageOldTest');
         $suite->addTestSuite('Zend_Mail_MaildirFolderTest');
         $suite->addTestSuite('Zend_Mail_MaildirWritableTest');
     }
     $suite->addTestSuite('Zend_Mail_SmtpOfflineTest');
     $suite->addTestSuite('Zend_Mail_SmtpProtocolTest');
     if (defined('TESTS_ZEND_MAIL_SMTP_ENABLED') && constant('TESTS_ZEND_MAIL_SMTP_ENABLED') == true) {
         $suite->addTestSuite('Zend_Mail_SmtpTest');
     }
     $suite->addTestSuite('Zend_Mail_FileTransportTest');
     return $suite;
 }