public function test_get_the_order_currency()
 {
     $currency = get_the_order_currency_name(self::$order->get_id());
     $this->assertEquals($currency, APP_Currencies::get_name(self::$order->get_currency()));
     $this->expectOutputString($currency);
     the_order_currency(self::$order->get_id());
 }
/**
 * Displays the name of the current order's currency
 * @return void
 */
function the_order_currency($order_id = null)
{
    echo get_the_order_currency_name($order_id);
}