Post Type Shortcode

//This ishortcode will print different type of post [post_list type="post/page"]
<?php
/*
Plugin Name: Stock Toolkit
*/
//This is registration of custom post type
add_action( 'init', 'rusho_custom_post' );
function rusho_custom_post() {
    register_post_type( 'testimonial',
        array(
            'labels' => array(
                'name' => __( 'Testimonials' ),
                'singular_name' => __( 'Testimonial' )
            ),
            'supports' => array('title', 'editor', 'thumbnail', 'page-attributes'),
            'public' => false,
            'show_ui' => true
        )
    );
}

function post_list_shortcode($atts){
    extract( shortcode_atts( array(
        'count' => -1,
        'type' => 'page',
    ), $atts) );

    $q = new WP_Query(
        array('posts_per_page' => $count,
              'post_type' => $type
              )
        );

    $list = '<ul>';
    while($q->have_posts()) : $q->the_post();
        $idd = get_the_ID();
        $post_content = get_the_content();
        $list .= '<li><a href="'.get_permalink().'">'.get_the_title().'</a></li>';
    endwhile;
    $list.= '</ul>';
    wp_reset_query();
    return $list;
}
add_shortcode('post_list', 'post_list_shortcode');