WooCommerce - Custom tab

functions.php

/**
 * Custom tab
 */
add_filter( 'woocommerce_product_tabs', 'ct_custom_tab' );
function ct_custom_tab( $tabs ) {
	
	// Adds the new tab
	$tabs['test_tab'] = array(
		'title' 	=> __( 'Custom Tab', 'woocommerce' ),
		'priority' 	=> 50,
		'callback' 	=> 'ct_custom_tab_content'
	);

	return $tabs;

}
function ct_custom_tab_content() {

	// The new tab content
	echo '<h3>My Custom Tab</h3>';
	echo '<p>Here\'s your new product tab!</p>';
	
}