add_action('woocommerce_add_to_cart', 'test_hook_firing', 10, 6);
function test_hook_firing($cart_item_key, $product_id, $quantity, $variation_id, $variation, $cart_item_data) {
error_log('TEST: woocommerce_add_to_cart hook fired for product: ' . $product_id);
}
