A Testimonials Custom Post Type in a PHP class

testimonials_custom_post_type.php

<?php
/*
Plugin Name: Pico Themes Testimonials
Plugin URI: http://wwww.picothemes.com/
Description: This plugin generates a custom post type for Testimonials
Author: Bronson Quick
Version: 1.0
Author URI: http://www.picothemes.com/
 */

class Pico_Testimonials {

    public function __construct()
    {
        add_action( 'init', array( &$this, 'register_cpt_testimonial'));
        add_action( 'add_meta_boxes', array ( &$this, 'pico_add_meta_boxes') );
        add_action( 'save_post', array( &$this, 'pico_save_testimonial_meta' ) );
        add_action( 'add_meta_boxes_testimonial',  array( &$this, 'pico_testimonials_add_meta_boxes' ) );
        add_filter( 'admin_post_thumbnail_html', array( &$this, 'pico_testimonials_post_thumbnail_html' ) );
        add_filter( 'post_updated_messages', array( &$this, 'pico_testimonial_updated_messages') );
    }

    public function register_cpt_testimonial() {
    $args = array(
        'public'        => true,
        'query_var'     => 'testimonial',
        'rewrite'       => array(
            'slug'          => 'testimonials',
            'with_front'    => false
        ),
        'supports' => array(
            'title',
            'editor',
            'author',
            'thumbnail',
            'revisions'
        ),
        'labels' => array(
            'name'                  => __( 'Testimonials', 'saas' ),
            'singular_name'         => __( 'Testimonial', 'saas' ),
            'add_new'               => __( 'Add New', 'saas' ),
            'add_new_item'          => __( 'Add New', 'saas' ),
            'edit_item'             => __( 'Edit Testimonial', 'saas' ),
            'new_item'              => __( 'New Testimonial', 'saas' ),
            'view_item'             => __( 'View Testimonial', 'saas' ),
            'search_items'          => __( 'Search Testimonials', 'saas' ),
            'not_found'             => __( 'No testimonials found', 'saas' ),
            'not_found_in_trash'    => __( 'No testimonials found in Trash', 'saas' ),
        ),
    );
    register_post_type( 'testimonial', $args );
    /* Register new image size for the testimonials */
    add_image_size( 'testimonial-thumbnail', 175, 128, true );
    }

    public function pico_add_meta_boxes() {
	    add_meta_box( 'pico_testimonials_meta_box', __( 'Testimonial Details' ), array( &$this, 'pico_testimonials_meta_box'), 'testimonial', 'side', 'core' );
    }

    public function pico_testimonials_meta_box() {
        global $post_ID;?>

        <div id="testimonial_meta">
        <?php wp_nonce_field( plugin_basename( __FILE__ ), 'pico_testimonial_nonce' );
        $business_name = get_post_meta( $post_ID, 'business_name', true );
        // Business Name ?>
        <p>
            <label for="business_name" style="display:inline-block;"><?php _e( "Business Name:" ); ?></label>
            <input type="text" id="business_name" name="business_name" value="<?php esc_attr_e( $business_name ); ?>" size="25" />
        </p>
        </div>
        <?php
    }

    public function pico_save_testimonial_meta() {
        if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE )
            return;
        if ( empty( $_POST[ 'pico_testimonial_nonce' ] ) || ! wp_verify_nonce( $_POST[ 'pico_testimonial_nonce' ], plugin_basename( __FILE__ ) ) )
            return;
        update_post_meta( $_POST[ 'ID' ], 'business_name', sanitize_text_field( $_POST[ 'business_name' ] ) );
    }

    public function pico_testimonials_add_meta_boxes() {
        remove_meta_box( 'postimagediv', 'testimonial', 'side' );
        add_meta_box( 'postimagediv', 'Testimonial Image', 'post_thumbnail_meta_box', 'testimonial', 'side' );
    }

    public function pico_testimonials_post_thumbnail_html( $output ) {
        global $post_type;

        // beware of translated admin
        if ( ! empty ( $post_type ) && 'testimonial' == $post_type ) {
            $output = str_replace( 'Set featured image', 'Select / Upload a testimonial image', $output );
            $output = str_replace( 'Remove featured image', 'Remove testimonial image', $output );
        }

        return $output;
    }
    public function pico_testimonial_updated_messages( $messages ) {
        global $post, $post_ID;
        $messages['testimonial'] = array(
            0 => '', // Unused. Messages start at index 1.
            1 => sprintf( __( 'Testimonial updated. <a href="%s">View testimonial</a>'), esc_url( get_permalink($post_ID) ) ),
            2 => __( 'Custom field updated.' ),
            3 => __( 'Custom field deleted.' ),
            4 => __( 'Testimonial updated.' ),
            /* translators: %s: date and time of the revision */
            5 => isset( $_GET[ 'revision' ]) ? sprintf( __( 'Testimonial restored to revision from %s' ), wp_post_revision_title( (int) $_GET[ 'revision' ], false ) ) : false,
            6 => sprintf( __( 'Testimonial published. <a href="%s">View testimonial</a>'), esc_url( get_permalink( $post_ID ) ) ),
            7 => __( 'Testimonial saved.' ),
            8 => sprintf( __( 'Testimonial submitted. <a target="_blank" href="%s">Preview testimonial</a>'), esc_url( add_query_arg( 'preview', 'true', get_permalink($post_ID) ) ) ),
            9 => sprintf( __( 'Testimonial scheduled for: <strong>%1$s</strong>. <a target="_blank" href="%2$s">Preview testimonial</a>' ),
              // translators: Publish box date format, see http://php.net/date
              date_i18n( __( 'M j, Y @ G:i' ), strtotime( $post->post_date ) ), esc_url( get_permalink( $post_ID ) ) ),
            10 => sprintf( __( 'Testimonial draft updated. <a target="_blank" href="%s">Preview testimonial</a>'), esc_url( add_query_arg( 'preview', 'true', get_permalink( $post_ID ) ) ) ),
        );
        return $messages;
    }
}
$pico_testimonial = new Pico_Testimonials();