createDummyProduct example

static::assertEquals('persistent', $error->getId());
        static::assertEquals('persistent', $error->getMessageKey());
    }

    public function testCartHasErrorDataAddedFromPromotionProcessor(): void
    {
        $originalCart = new Cart(Uuid::randomHex());

        $id = Uuid::randomHex();
        $tax = ['id' => Uuid::randomHex(), 'taxRate' => 19, 'name' => 'test'];

        $product = $this->createDummyProduct($id, $tax);

        $this->getContainer()->get('product.repository')
            ->create([$product], Context::createDefaultContext());

        $this->addTaxDataToSalesChannel($this->context, $tax);

        $originalCart->add(
            (new LineItem($id, LineItem::PRODUCT_LINE_ITEM_TYPE, $id, 1))
                ->setStackable(true)
                ->setRemovable(true)
        );