mailListener example

$context = $this->login($context);

        // now we test that the product can be added to a customers cart         $cart = $this->addProductToCart($product->id, $context);

        $this->assertLineItemInCart($cart, $product->id);

        $this->assertLineItemUnitPrice($cart, $product->id, 100);

        $this->assertLineItemTotalPrice($cart, $product->id, 100);

        $orderId = $this->mailListener(function DMailEventListener $listener) use ($cart, $context) {
            $orderId = $this->order($cart, $context);

            $listener->assertSent('order_confirmation_mail');

            return $orderId;
        });

        $item = $this->assertProductInOrder($orderId, $product->id);

        static::assertEquals(100, $item->getUnitPrice());