PHP Mail Script Test

<?php

    /*
    DONT FORGET TO DELETE THIS SCRIPT WHEN FINISHED!
    */

    ini_set( 'display_errors', 1 );
    error_reporting( E_ALL );

    $from = '[email protected]';

    /*
    ini_set( 'SMTP', 'smtp.example.com' );
    ini_set( 'SMTP_PORT', 25 );
    ini_set( 'sendmail_from', $from );
    */

    $server = array(
        'HTTP_HOST', 'SERVER_NAME', 'SERVER_ADDR', 'SERVER_PORT',
        'SERVER_ADMIN', 'SERVER_SIGNATURE', 'SERVER_SOFTWARE',
        'REMOTE_ADDR', 'DOCUMENT_ROOT', 'REQUEST_URI',
        'SCRIPT_NAME', 'SCRIPT_FILENAME',
    );

    $to      = ( isset( $_GET['email'] ) ? $_GET['email'] : FALSE );
    $subject = 'Mail Test Successful for ' . $_SERVER['HTTP_HOST'];
    $message = '';

    if ( ! $to )
    {
        echo '<strong>Set $_GET[\'email\'].</strong>';
        exit;
    };

    foreach ( $server as $s )
    {
        $message .= sprintf( '%s: %s', $s, $_SERVER[$s] ) . PHP_EOL;
    };

    $headers = 'From: ' . $from . PHP_EOL
         . 'Reply-To: ' . $from . PHP_EOL
         . 'X-Mailer: PHP/' . phpversion();

    if ( isset( $_GET['send'] ) && $_GET['send'] === 'true' )
    {
        $success = mail( $to, $subject, $message, $headers );
    }
    else
    {
        echo '<strong>&quot;<a href="/mail_test.php?email=' . $to . '&send=true">'
         . '/mail_test.php?email=' . $to . '&send=true</a>&quot; to send a test e-mail.</strong>';
    };

    if ( isset( $success ) )
    {
        echo 'E-mail sent to: ' . $to;
        echo '<br />';
        echo 'Successful mail?: <strong ' . ( $success ? 'style="color:green;">YES' : 'style="color:red;">NO' ) . '</strong>';
    }
    else
    {
        echo '<br />';
        echo 'E-mail set as: '.$to;
    };

    echo '<hr />';
    echo '<style>   * { font-family: Helvetica, Arial, sans-serif;  } th { text-align: left; } td { padding: 3px 5px; } </style>';
    echo '<table>';

    foreach ( $server as $s )
    {
        echo '<tr><th>$_SERVER[\'' . $s . '\']</th><td>' . $_SERVER[$s] . '</td></tr>';
    };

    echo '</table>';

    if ( isset( $success ) )
    {
        echo '<!--';
        var_dump( $success );
        echo '-->';
    };
?>