Variations and Colour Swatches custom class or ID

customize_class_id.php

// change output $args in variation swatches 
function change_class_or_id( $args ) {
	$args = array(
	    'options' => false,
	    'attribute' => false,
	    'product' => false,
	    'selected' => false,
	    'name' => '',
	    'id' => 'testyyy',
	    'class' => 'test',
	    'show_option_none' => __( 'Choose an option', 'woocommerce' )
		);
	return $args;
}

add_filter( 'woocommerce_dropdown_variation_attribute_options_args', 'change_class_or_id' );