In Wordpress, how do I display a single random post of a custom post type in a sidebar widget?
If you want you can directly paste following code snippet in your sidebar.php where you want to show the Testimonials (make sure whether it's testimonials/Testimonials)
<?php $args = array( 'post_type'=>'testimonials', 'orderby'=>'rand', 'posts_per_page'=>'1' ); $testimonials=new WP_Query($args); while ($testimonials->have_posts()) : $testimonials->the_post(); ?> <h2><a href="<?php the_permalink() ?>"><?php the_title(); ?></a></h2> <p><?php the_excerpt(); // or the_content(); ?></p><?php endwhile; wp_reset_postdata();?>