按类别名称检索wp\U术语

“category\u name”不是get\u术语的有效参数。 这个 WP reference documentation here

'名称'

因此,假设要搜索的名称是$cat,请尝试将get\u terms参数更改为:

$terms = get_terms( array(
        'taxonomy' => 'testimonial',
        'name' => $cat,
        'hide_empty' => true,
        ) );

更新:

get_terms 仅返回有关 您按照原始问题搜索。

获取所有 帖子 get_posts 和 tax_query 具体如下:

    $myposts = get_posts(array(
        'showposts' => -1, // get all posts
        'post_type' => 'post', // change to whatever post type you want, or leave out if you want to get all post types
        'tax_query' => array( 
                          array( 
                            'taxonomy' => 'testimonial', 
                            'field' => 'name', 
                            'terms' => $cat
                         ))
    ));

get_posts documentation in WP Codex

function testimonial_shortcode( $atts ) {

    $cat = $atts['cat'];

            $testim='<div id="owl-demo" class="owl-carousel owl-theme">';    
        $terms = get_terms( array(
            'taxonomy' => 'testimonial',
            'name' => $cat,
            'hide_empty' => true,
            ) );
        foreach($terms as $custom_texonomy){
            $imageid=get_option("testimonial_".$custom_texonomy->term_id."_testimonials__image");

            $imgurl=wp_get_attachment_image_src( $imageid, 'full');

            $testim.=' <div class="item">
    ...

    }
    add_shortcode( 'testimonialcat', 'testimonial_shortcode' );