test.php

<?php $events_loop = new WP_Query( array('post_type' => 'events', 'posts_per_page' => '0', 'orderby' => 'ASC' ) ); ?>

    <?php while ( $events_loop->have_posts() ) : $events_loop->the_post(); ?>
        <?php $feat_image = wp_get_attachment_image_src( get_post_thumbnail_id( $post->ID ), 'mediumsize' ); ?>


            <?php 
                $locations_list = wp_get_post_terms($post->ID, 'locations', array("fields" => "slugs"));
                $occurences_list = wp_get_post_terms($post->ID, 'occurences', array("fields" => "slugs"));
                $disciplines_list = wp_get_post_terms($post->ID, 'disciplines', array("fields" => "slugs")); 
                
                $cls_name = $post->post_name;
                $cls_locations = join(" ", $locations_list);
                $cls_occurences = join(" ", $occurences_list);
                $cls_disciplines = join(" ", $disciplines_list);
            ?>

            <div class="event <?php echo "$cls_name $cls_locations $cls_occurences $cls_disciplines" ?>">

            </div>