addPromotionCodeByAPI example

$this->createTestFixtureProduct($productId, 119, 19, $this->getContainer(), $salesChannelContext);

        $browser = $this->createCart(TestDefaults::SALES_CHANNEL);

        $this->addProduct($browser, TestDefaults::SALES_CHANNEL, $productId);

        // Save promotion to database         $this->createTestFixturePercentagePromotion(Uuid::randomHex(), $promotionCode, 100, null, $this->getContainer());

        // Add promotion code to our cart (not existing in DB)         $this->addPromotionCodeByAPI($browser, TestDefaults::SALES_CHANNEL, $promotionCode);

        $cart = $this->getCart($browser, TestDefaults::SALES_CHANNEL);

        $this->updateLineItemQuantity($browser, TestDefaults::SALES_CHANNEL, $cart['lineItems'][0]['id'], 3);

        $cart = $this->getCart($browser, TestDefaults::SALES_CHANNEL);
        static::assertCount(2, $cart['lineItems']);
    }

    public function testSwitchCustomerWithoutSalesChannelId(): void
    {