WordPress Text Editor Buttons not showing

Question

So, I have here a custom post type in WordPress and everything is working except when I tried to add a new item and switch from visual editor to text editor and I found out that there are no buttons available. Usually in the Text Editor have these buttons "B", "i", "link", "ins", "img", "ul" and etc..

it's kind of weird, since the Pages and Posts had those buttons. Below is the code where I tried to add a custom post type function.

add_action( 'init', '___regPostType' ) ;

function ___regPostType() {

$labels = array(

    'name' => _x('Custom Post Type', 'post type general name'),
    'singular_name' => _x('Test Post', 'post type singular name'),
    'add_new' => _x('Add New Item', 'test item'),
    'add_new_item' => __('Add New Item'),
    'edit_item' => __('Edit Item'),
    'new_item' => __('New Item'),
    'view_item' => __('View Item Page'),
    'search_items' => __('Search Item'),
    'not_found' =>  __('Nothing found'),
    'not_found_in_trash' => __('Nothing found in Trash'),
    'parent_item_colon' => ''

);

$args = array(

    'labels' => $labels,
    'public' => true,
    'publicly_queryable' => true,
    'show_ui' => true,
    'query_var' => true,
    'menu_icon' => 'dashicons-welcome-learn-more',
    'rewrite' => true,
    'capability_type' => 'post',
    'hierarchical' => false,
    'menu_position' => null,
    'supports' => array('title','editor','thumbnail')

); 

register_post_type( 'test' , $args );

}

I am not sure if there's a parameter missing or a function missing here but I hope someone can figure it out...