Taxonomy category shortcode

funcation.php

<?php // Taxonomy category shortcode
function cat_func($atts) {
    extract(shortcode_atts(array(
            'class_name'    => 'cat-post',
            'totalposts'    => '-1',
            'category'      => '',
            'thumbnail'     => 'false',
            'excerpt'       => 'true',
            'orderby'       => 'post_date'
            ), $atts));

    $output = '<div class="'.$class_name.'">';
    global $post;
    $args = array(
        'posts_per_page' => $totalposts, 
        'orderby' => $orderby,
        'post_type' => 'inventory',
        'tax_query' => array(
            array(
                'taxonomy' => 'inventory-category',
                'field' => 'slug',
                'terms' => array( $category)
            )
        ));
    $myposts = NEW WP_Query($args);


    while($myposts->have_posts()) {
        $myposts->the_post();
        $output .= '<div class="cat-post-list">';
        if($thumbnail == 'true') {
        $output .= '<div class="cat-post-images">'.get_the_post_thumbnail($post->ID, 'thumbnail').'</div>';
        }
        $output .= '<div class="cat-content"><span class="cat-post-title"><a href="'.get_permalink().'">'.get_the_title().'</a></span>';
        if ($excerpt == 'true') {
            $output .= '<span class="cat-post-excerpt">'.get_the_excerpt().'</span>';
        }
        $output .= '</div>
            <div class="cat-clear"></div>
        </div>';
    };
    $output .= '</div>';
    wp_reset_query();
    return $output;
}
add_shortcode('inventory-category', 'cat_func');
?>

[inventory-category totalposts="3" category="bulk-racks" thumbnail="true" excerpt="true" ]