diff --git a/Controller/Api/Push.php b/Controller/Api/Push.php
index 43c1c9f..7db16ad 100644
--- a/Controller/Api/Push.php
+++ b/Controller/Api/Push.php
@@ -1,10 +1,12 @@
 <?php
+
 /**
  * Copyright © Klarna Bank AB (publ)
  *
  * For the full copyright and license information, please view the NOTICE
  * and LICENSE files that were distributed with this source code.
  */
+
 declare(strict_types=1);
 
 namespace Klarna\Kco\Controller\Api;
@@ -21,12 +23,10 @@
 use Magento\Framework\App\Action\HttpPostActionInterface;
 use Magento\Framework\App\RequestInterface;
 use Magento\Framework\Controller\Result\Json;
-use Magento\Framework\Controller\ResultInterface;
 use Magento\Framework\DataObjectFactory;
 use Magento\Framework\Exception\AlreadyExistsException;
 use Magento\Framework\Exception\LocalizedException;
 use Klarna\Base\Controller\CsrfAbstract;
-use Magento\Framework\DataObject;
 use Magento\Quote\Model\CartLockedException;
 
 /**
@@ -41,30 +41,32 @@ class Push extends CsrfAbstract implements HttpPostActionInterface
      * @var LoggerInterface
      */
     private $logger;
+
     /**
      * @var CheckoutOrder
      */
     private $checkoutOrder;
-    /**
-     * @var DataObjectFactory
-     */
-    private $dataObjectFactory;
+
     /**
      * @var Result
      */
     private $result;
+
     /**
      * @var Logger
      */
     private $apiLogger;
+
     /**
      * @var Container
      */
     private $container;
+
     /**
      * @var WorkflowProvider
      */
     private WorkflowProvider $workflowProvider;
+
     /**
      * @var RequestInterface
      */
@@ -79,12 +81,11 @@ class Push extends CsrfAbstract implements HttpPostActionInterface
      * @param Container $container
      * @param WorkflowProvider $workflowProvider
      * @param RequestInterface $request
-     * @codeCoverageIgnore
      */
     public function __construct(
         LoggerInterface $logger,
         CheckoutOrder $checkoutOrder,
-        DataObjectFactory $dataObjectFactory,
+        DataObjectFactory $dataObjectFactory, // To be removed as unused in next major release!
         Result $result,
         Logger $apiLogger,
         Container $container,
@@ -93,7 +94,6 @@ public function __construct(
     ) {
         $this->logger = $logger;
         $this->checkoutOrder = $checkoutOrder;
-        $this->dataObjectFactory = $dataObjectFactory;
         $this->result = $result;
         $this->apiLogger = $apiLogger;
         $this->container = $container;
@@ -104,141 +104,118 @@ public function __construct(
     /**
      * Performing the push action logic
      *
-     * @return Json|ResultInterface
-     * @throws KlarnaException
-     * @throws LocalizedException
-     * phpcs:disable Commenting.EmptyCatchComment
+     * @inheritDoc
      */
     public function execute()
     {
         $klarnaOrderId = $this->request->getParam('id');
         $this->workflowProvider->setKlarnaOrderId($klarnaOrderId);
-
-        try {
-            $magentoOrder = $this->workflowProvider->getMagentoOrder();
-            // phpcs:ignore Magento2.CodeAnalysis.EmptyBlock.DetectedCatch
-        } catch (KlarnaException $e) {
-            $this->logger->debug(
-                'No order is created because a payment method is selected with an external redirect.'
-            );
-            // We do nothing since when using for example the IDEAL payment no order is created at this point
-        }
-
         $this->logger->debug('Push: klarna order id: ' . $klarnaOrderId);
 
-        try {
-            $this->checkoutOrder->updateOrderState($klarnaOrderId);
-        } catch (KlarnaException $e) {
-            return $this->createOrder($klarnaOrderId);
-        } catch (LocalizedException $e) {
-            $this->apiLogger->logCallbackException(
-                $this->container,
-                ApiInterface::ACTIONS['push'],
-                $this->request,
-                $e
-            );
-            return $this->cancelKlarnaOrder($klarnaOrderId, $e);
+        $createOrderStatus = $this->canCreateOrder() ? $this->createOrder($klarnaOrderId) : true;
+        if ($createOrderStatus instanceof Json) {
+            return $createOrderStatus;
         }
 
-        $magentoOrder = $this->checkoutOrder->getMagentoOrder();
-        $this->container->setIncrementId($magentoOrder->getIncrementId());
-        $this->container->setService(ServiceInterface::SERVICE_KCO);
-        $this->apiLogger->logCallback($this->container, ApiInterface::ACTIONS['push'], $this->request, []);
-
-        return $this->getSuccessResponse();
-    }
-
-    /**
-     * Canceling the Klarna order
-     *
-     * @param string             $klarnaOrderId
-     * @param LocalizedException $e
-     * @return Json
-     * @throws KlarnaException
-     */
-    private function cancelKlarnaOrder(string $klarnaOrderId, LocalizedException $e): Json
-    {
-        $this->logger->critical('Push: Cancelling order. Error occured: ' . $e->getMessage());
-        $responseCodeObject = $this->getFailureResponseObject(500);
-        $this->checkoutOrder->cancelKlarnaOrder($klarnaOrderId, $e->getMessage());
-
-        return $this->result->getJsonResult(
-            (int)$responseCodeObject->getResponseCode(),
-            ['error' => $e->getMessage()]
-        );
+        return $this->updateOrderState($klarnaOrderId);
     }
 
     /**
-     * Getting back the success response
-     *
-     * @return Json
+     * @return bool
      */
-    private function getSuccessResponse(): Json
+    private function canCreateOrder(): bool
     {
-        $this->logger->debug('Push: success');
-        return $this->result->getJsonResult(200);
-    }
+        // TODO: We shouldn't need to rely on exception + it can result in false positives, let's eventually add
+        // possibility to figure out existence of these instances by something more simplified
 
-    /**
-     * Getting back the failure response object with the given response code
-     *
-     * @param int $responseCode
-     * @return DataObject
-     */
-    private function getFailureResponseObject(int $responseCode): DataObject
-    {
-        $object = $this->dataObjectFactory->create();
-        $object->setResponseCode($responseCode);
+        try {
+            $this->workflowProvider->getMagentoOrder();
+            $this->workflowProvider->getKlarnaOrder();
 
-        return $object;
+            return false;
+        } catch (KlarnaException $exception) {
+            return true;
+        }
     }
 
     /**
      * @param string $klarnaOrderId
-     * @param CartLockedException $e
      *
-     * @return Json
+     * @return Json|true
      */
-    private function getCartLockedResponse(string $klarnaOrderId, CartLockedException $e): Json
+    private function createOrder(string $klarnaOrderId)
     {
-        $this->logger->debug(
-            'Push: Retry order ' . $klarnaOrderId . ' - Exception: ' . $e->getMessage()
-        );
-        return $this->result->getJsonResult(
-            503,
-            ['error' => $e->getMessage()]
-        );
+        $this->logger->debug('Push: Attempting to create order by id ' . $klarnaOrderId);
+
+        try {
+            $this->checkoutOrder->createMagentoOrder($klarnaOrderId);
+            $this->checkoutOrder->sendCustomerMail();
+        } catch (AlreadyExistsException $exception) {
+            $this->logger->debug('Push: Order already exists for this Klarna order id: ' . $klarnaOrderId);
+        } catch (CartLockedException $exception) {
+            $this->logger->debug('Push: Retry order ' . $klarnaOrderId . ' - Exception: ' . $exception->getMessage());
+
+            return $this->result->getJsonResult(
+                503,
+                ['error' => $exception->getMessage()]
+            );
+        } catch (LocalizedException $e) {
+            if ($this->checkoutOrder->isMagentoOrderExists($klarnaOrderId)) {
+                $this->logger->debug('Push: Order already created by concurrent request: ' . $klarnaOrderId);
+
+                return true;
+            }
+
+            $this->logger->debug('Push: Order creation failed: ' . $e->getMessage());
+
+            $this->apiLogger->logCallbackException(
+                $this->container,
+                ApiInterface::ACTIONS['push'],
+                $this->request,
+                $e
+            );
+
+            return $this->result->getJsonResult(
+                500,
+                ['error' => 'Failed to create order']
+            );
+        }
+
+        $this->logger->debug('Push: Order created successfully by id ' . $klarnaOrderId);
+
+        return true;
     }
 
     /**
-     * Create order in Magento if it doesn't currently exist.
-     *
-     * This is the case when the customer selected a payment gateway method (for example "iDeal").
-     *
      * @param string $klarnaOrderId
+     *
      * @return Json
-     * @throws KlarnaException
      */
-    private function createOrder(string $klarnaOrderId): Json
+    private function updateOrderState(string $klarnaOrderId): Json
     {
         try {
-            $this->checkoutOrder->createMagentoOrder($klarnaOrderId);
-            $this->checkoutOrder->sendCustomerMail();
             $this->checkoutOrder->updateOrderState($klarnaOrderId);
-        } catch (AlreadyExistsException $e) {
-            $this->logger->debug('Push: Order already exists for this Klarna order id: ' . $klarnaOrderId);
-        } catch (CartLockedException $e) {
-            return $this->getCartLockedResponse($klarnaOrderId, $e);
         } catch (LocalizedException $e) {
-            // Before cancelling, check if a concurrent push already created the order successfully.
-            // If the Magento order exists, return success to avoid voiding a valid Klarna authorization.
-            $magentoOrder = $this->checkoutOrder->getMagentoOrder();
-            if ($magentoOrder !== null && $magentoOrder->getId()) {
-                $this->logger->debug('Push: Order already created by concurrent request: ' . $klarnaOrderId);
-                return $this->getSuccessResponse();
-            }
-            return $this->cancelKlarnaOrder($klarnaOrderId, $e);
+            $this->apiLogger->logCallbackException(
+                $this->container,
+                ApiInterface::ACTIONS['push'],
+                $this->request,
+                $e
+            );
+
+            return $this->result->getJsonResult(
+                500,
+                ['error' => 'Failed to update order state']
+            );
         }
-        return $this->getSuccessResponse();
+
+        $magentoOrder = $this->checkoutOrder->getMagentoOrder();
+        $this->container->setIncrementId($magentoOrder->getIncrementId());
+        $this->container->setService(ServiceInterface::SERVICE_KCO);
+        $this->apiLogger->logCallback($this->container, ApiInterface::ACTIONS['push'], $this->request, []);
+
+        $this->logger->debug('Push: success');
+
+        return $this->result->getJsonResult(200);
     }
 }
diff --git a/Controller/Klarna/Confirmation.php b/Controller/Klarna/Confirmation.php
index 1f8660d..dde10df 100644
--- a/Controller/Klarna/Confirmation.php
+++ b/Controller/Klarna/Confirmation.php
@@ -1,17 +1,18 @@
 <?php
+
 /**
  * Copyright © Klarna Bank AB (publ)
  *
  * For the full copyright and license information, please view the NOTICE
  * and LICENSE files that were distributed with this source code.
  */
+
 declare(strict_types=1);
 
 namespace Klarna\Kco\Controller\Klarna;
 
 use Klarna\Kco\Model\Checkout\Url;
 use Magento\Framework\App\Action\HttpGetActionInterface;
-use Magento\Framework\Controller\ResultInterface;
 use Magento\Framework\Exception\AlreadyExistsException;
 use Magento\Framework\Exception\NoSuchEntityException;
 use Klarna\Kco\Model\Order\Order as CheckoutOrder;
@@ -36,22 +37,27 @@ class Confirmation implements HttpGetActionInterface
      * @var Url
      */
     private $url;
+
     /**
      * @var CheckoutOrder
      */
     private $checkoutOrder;
+
     /**
      * @var LoggerInterface
      */
     private $logger;
+
     /**
      * @var RequestInterface
      */
     private RequestInterface $request;
+
     /**
      * @var RedirectFactory
      */
     private RedirectFactory $redirectFactory;
+
     /**
      * @var ManagerInterface
      */
@@ -64,7 +70,6 @@ class Confirmation implements HttpGetActionInterface
      * @param RequestInterface $request
      * @param RedirectFactory $redirectFactory
      * @param ManagerInterface $messageManager
-     * @codeCoverageIgnore
      */
     public function __construct(
         Url $url,
@@ -83,15 +88,12 @@ public function __construct(
     }
 
     /**
-     * Performing the confirmation action
-     *
-     * @return $this|ResultInterface
-     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
+     * @inheritDoc
      */
     public function execute()
     {
         $klarnaOrderId = $this->request->getParam('id');
-        $this->logger->debug('Klarna order id: ' . $klarnaOrderId);
+        $this->logger->debug('Kustom order id: ' . $klarnaOrderId);
 
         if (!$klarnaOrderId) {
             return $this->getInvalidOrderIdResponse();
@@ -102,18 +104,20 @@ public function execute()
             $this->checkoutOrder->sendCustomerMail();
         } catch (CartLockedException $e) {
             $this->logger->debug('Confirmation: push running concurrently: ' . $klarnaOrderId . ' - Exception: ' . $e->getMessage());
+
             return $this->getSuccessResponse();
         } catch (AlreadyExistsException $e) {
-            return $this->getOrderAlreadyExistsResponse();
+            $this->logger->debug('Confirmation: push running concurrently: ' . $klarnaOrderId . ' - Exception: ' . $e->getMessage());
+
+            return $this->getSuccessResponse();
         } catch (LocalizedException $e) {
-            // Before cancelling, check if a concurrent push already created the order successfully.
-            // If the Magento order exists, return success to avoid voiding a valid Klarna authorization.
-            $magentoOrder = $this->checkoutOrder->getMagentoOrder();
-            if ($magentoOrder !== null && $magentoOrder->getId()) {
+            if ($this->checkoutOrder->isMagentoOrderExists($klarnaOrderId)) {
                 $this->logger->debug('Confirmation: Order already created by concurrent request: ' . $klarnaOrderId);
+
                 return $this->getSuccessResponse();
             }
-            return $this->getErrorResponse($e, $klarnaOrderId);
+
+            return $this->getErrorResponse($e);
         }
 
         return $this->getSuccessResponse();
@@ -127,6 +131,7 @@ public function execute()
     private function getSuccessResponse(): Redirect
     {
         $this->logger->debug('Confirmation: Success');
+
         return $this->redirectFactory->create()->setPath(Url::CHECKOUT_ACTION_PREFIX . '/success');
     }
 
@@ -134,13 +139,12 @@ private function getSuccessResponse(): Redirect
      * Returning a general error response
      *
      * @param KlarnaException|NoSuchEntityException|CouldNotSaveException|LocalizedException $e
-     * @param string $klarnaOrderId
+     *
      * @return Redirect
      */
-    private function getErrorResponse($e, string $klarnaOrderId): Redirect
+    private function getErrorResponse($e): Redirect
     {
         $this->logger->critical($e);
-        $this->checkoutOrder->cancelKlarnaOrder($klarnaOrderId, $e->getMessage());
         $this->messageManager->addErrorMessage($e->getMessage());
 
         return $this->redirectFactory->create()->setUrl($this->url->getFailureUrl());
@@ -154,19 +158,7 @@ private function getErrorResponse($e, string $klarnaOrderId): Redirect
     private function getInvalidOrderIdResponse(): Redirect
     {
         $this->messageManager->addErrorMessage(__('Unable to process order. Please try again'));
-        return $this->redirectFactory->create()->setUrl($this->url->getFailureUrl());
-    }
-
-    /**
-     * Returning a response for the case the order already exists
-     *
-     * @return Redirect
-     */
-    private function getOrderAlreadyExistsResponse(): Redirect
-    {
-        $this->logger->debug('Confirmation: Order already exist');
 
-        $this->messageManager->addErrorMessage(__('Order already exist.'));
         return $this->redirectFactory->create()->setUrl($this->url->getFailureUrl());
     }
 }
diff --git a/Model/Order/Order.php b/Model/Order/Order.php
index 30b262e..2d48306 100644
--- a/Model/Order/Order.php
+++ b/Model/Order/Order.php
@@ -253,7 +253,7 @@ public function createMagentoOrder(string $klarnaOrderId): MagentoOrderInterface
         $this->klarnaOrder = $this->workflowProvider->getKlarnaOrder();
         $this->klarnaOrder->setReservationId($reservationId);
         $this->orderRepository->save($this->klarnaOrder);
-        $this->logger->debug('Saved the klarna order');
+        $this->logger->debug('Saved the Kustom order');
 
         return $this->mageOrder;
     }
@@ -295,7 +295,7 @@ public function setOrderStatus(MagentoOrderInterface $order, string $status = ''
         }
 
         if (SalesOrder::STATE_PROCESSING === $order->getState()) {
-            $order->addStatusHistoryComment(__('Order processed by Klarna.'), $status);
+            $order->addStatusHistoryComment(__('Order processed by Kustom.'), $status);
         }
     }
 
@@ -332,7 +332,7 @@ public function cancelKlarnaOrder(string $klarnaOrderId, string $cancelReason):
             }
             if ($order->getStatus() !== 'CANCELLED') {
                 $orderManagement->cancel($klarnaId);
-                $this->logger->info('Canceled order with Klarna - ' . $cancelReason);
+                $this->logger->info('Canceled order with Kustom - ' . $cancelReason);
             }
 
             if ($magentoOrder !== null && !$magentoOrder->isCanceled()) {
@@ -369,7 +369,7 @@ public function updateOrderState(string $klarnaOrderId): void
         // TODO: Consider saving cancel status in database klarna table
         if ($klarnaStatus === KcoApiInterface::ORDER_STATUS_CANCELLED) {
             $this->logger->info(
-                'Klarna order is ' . $klarnaStatus . '. Cancelling Magento order: '
+                'Kustom order is ' . $klarnaStatus . '. Cancelling Magento order: '
                 . $this->mageOrder->getIncrementId()
             );
             $this->cancelMagentoOrder($this->mageOrder, $klarnaStatus);
@@ -396,7 +396,7 @@ public function updateOrderState(string $klarnaOrderId): void
     private function cancelOrder(MagentoOrderInterface $order, string $klarnaOrderId): void
     {
         if ($order->isCanceled()) {
-            $this->logger->debug('Cancel the order on the klarna side because it is canceled in the shop');
+            $this->logger->debug('Cancel the order on the Kustom side because it is canceled in the shop');
             $this->cancelKlarnaOrder($klarnaOrderId, 'Order Canceled in Magento');
         }
     }
@@ -432,12 +432,12 @@ private function cancelMagentoOrder(MagentoOrderInterface $order, string $klarna
         $order->setState(SalesOrder::STATE_CANCELED);
         $order->setStatus(SalesOrder::STATE_CANCELED);
         $order->addStatusHistoryComment(
-            __('Order automatically cancelled because Klarna status is: %1', $klarnaStatus)
+            __('Order automatically cancelled because Kustom status is: %1', $klarnaStatus)
         );
         $this->mageOrderRepository->save($order);
 
         $this->logger->info(
-            'Magento order ' . $order->getIncrementId() . ' cancelled due to Klarna status: ' . $klarnaStatus
+            'Magento order ' . $order->getIncrementId() . ' cancelled due to Kustom status: ' . $klarnaStatus
         );
     }
 
@@ -469,7 +469,7 @@ private function updateOrderWithKlarnaReference(
             }
         }
 
-        $this->logger->debug('Updated the order with the klarna reference');
+        $this->logger->debug('Updated the order with the Kustom reference');
     }
 
     /**
@@ -503,7 +503,7 @@ private function acknowledgeOrder(
                 // TODO: Consider: Should we cancel order in Magento here?
                 throw new KlarnaException(__('Acknowledge call failed. Check log for details.'));
             }
-            $order->addStatusHistoryComment('Acknowledged request sent to Klarna');
+            $order->addStatusHistoryComment('Acknowledged request sent to Kustom');
             $klarnaOrder->setIsAcknowledged(1);
             $this->orderRepository->save($klarnaOrder);
         }
@@ -544,7 +544,7 @@ public function checkAndUpdateOrderState(string $orderId): void
 
         $orderDetails = $this->paymentStatus->getStatusUpdate($klarnaOrder);
         if (!$orderDetails->getIsSuccessful()) {
-            throw new LocalizedException(__('An error happened when retrieving the status of the order from Klarna'));
+            throw new LocalizedException(__('An error happened when retrieving the status of the order from Kustom'));
         }
 
         $this->checkOrderState($mageOrder, $orderDetails->getStatus());
@@ -552,7 +552,7 @@ public function checkAndUpdateOrderState(string $orderId): void
             return;
         }
 
-        throw new LocalizedException(__('Order is still PENDING with Klarna'));
+        throw new LocalizedException(__('Order is still PENDING with Kustom'));
     }
 
     /**
@@ -570,7 +570,7 @@ private function getKlarnaOrderByMagentoOrder(MagentoOrderInterface $mageOrder):
             $this->denyPayment(
                 $mageOrder,
                 __(
-                    'Canceled the order since no Klarna information could ' .
+                    'Canceled the order since no Kustom information could ' .
                     'be found in the Magento database for the order.'
                 )
             );
@@ -614,7 +614,7 @@ private function checkOrderState(MagentoOrderInterface $mageOrder, string $statu
         if (in_array($status, $stopStatuses)) {
             $this->denyPayment(
                 $mageOrder,
-                __('Canceled the order as Klarna shows it as %1', $status)
+                __('Canceled the order as Kustom shows it as %1', $status)
             );
         }
     }
@@ -652,4 +652,21 @@ public function getMagentoOrder(): ?MagentoOrderInterface
     {
         return $this->mageOrder;
     }
+
+    /**
+     * @param string $klarnaOrderId
+     *
+     * @return bool
+     */
+    public function isMagentoOrderExists(string $klarnaOrderId): bool
+    {
+        try {
+            $this->workflowProvider->setKlarnaOrderId($klarnaOrderId);
+            $order = $this->workflowProvider->getMagentoOrder();
+
+            return (bool) $order->getId();
+        } catch (KlarnaException $exception) {
+            return false;
+        }
+    }
 }
diff --git a/Test/Integration/Controller/Api/PushTest.php b/Test/Integration/Controller/Api/PushTest.php
new file mode 100644
index 0000000..c291ee2
--- /dev/null
+++ b/Test/Integration/Controller/Api/PushTest.php
@@ -0,0 +1,558 @@
+<?php
+
+/**
+ * Copyright © Klarna Bank AB (publ)
+ *
+ * For the full copyright and license information, please view the NOTICE
+ * and LICENSE files that were distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Klarna\Kco\Test\Integration\Controller\Api;
+
+use Klarna\Backend\Model\Api\Rest\Service\Ordermanagement;
+use Klarna\Base\Model\OrderFactory as KlarnaOrderFactory;
+use Klarna\Kco\Model\Api\Rest\Service\Checkout;
+use Magento\Framework\App\Request\Http;
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Lock\LockManagerInterface;
+use Magento\Quote\Model\CartMutex;
+use Magento\Quote\Model\QuoteManagement;
+use Magento\Sales\Model\OrderFactory as MagentoOrderFactory;
+use Magento\TestFramework\TestCase\AbstractController;
+use PHPUnit\Framework\MockObject\MockObject;
+
+class PushTest extends AbstractController
+{
+    /**
+     * @var KlarnaOrderFactory
+     */
+    private $kOrderFactory;
+
+    /**
+     * @var MagentoOrderFactory
+     */
+    private $mOrderFactory;
+
+    /**
+     * @var Checkout|MockObject
+     */
+    private $checkoutMock;
+
+    /**
+     * @var Ordermanagement|MockObject
+     */
+    private $orderManagementMock;
+
+    /**
+     * @inheritDoc
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->kOrderFactory = $this->_objectManager->create(KlarnaOrderFactory::class);
+        $this->mOrderFactory = $this->_objectManager->create(MagentoOrderFactory::class);
+        $this->checkoutMock = $this->createMock(Checkout::class);
+        $this->_objectManager->addSharedInstance($this->checkoutMock, Checkout::class);
+        $this->orderManagementMock = $this->createMock(Ordermanagement::class);
+        $this->_objectManager->addSharedInstance($this->orderManagementMock, Ordermanagement::class);
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/klarna_order_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldSuccessfullyAcknowledgeUnacknowledgedOrder(): void
+    {
+        $expectedResponse = '[]';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'captured_amount' => 0,
+                'captures' => [],
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->any())->method('updateMerchantReferences')
+            ->willReturn([]);
+        $this->orderManagementMock->expects($this->any())->method('acknowledgeOrder')
+            ->willReturn(['is_successful' => true]);
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '1',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                    'klarna_reference' => '12345',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/klarna_order_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldSuccessfullyCancelOrderByCancelStatusInOrderData(): void
+    {
+        $expectedResponse = '[]';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'captured_amount' => 0,
+                'captures' => [],
+                'klarna_reference' => '12345',
+                'status' => 'CANCELLED',
+            ]);
+        $this->orderManagementMock->expects($this->any())->method('updateMerchantReferences')
+            ->willReturn([]);
+        $this->orderManagementMock->expects($this->any())->method('acknowledgeOrder')
+            ->willReturn(['is_successful' => true]);
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'canceled',
+                'status' => 'canceled',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoConfigFixture current_store klarna/api/debug 1
+     * @magentoConfigFixture current_store general/region/state_required ''
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldSuccessfullyCreateOrderByCheckoutApiResponse(): void
+    {
+        $expectedResponse = '[]';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'billing_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'shipping_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'order_id' => $klarnaOrderId,
+                'is_successful' => true,
+                'order_lines' => [
+                    [
+                        'image_url' => '',
+                        'name' => 'Simple Product',
+                        'product_url' => 'http://localhost/index.php/simple-product.html',
+                        'quantity' => 1,
+                        'reference' => 'simple',
+                        'tax_rate' => 0,
+                        'total_amount' => 1000,
+                        'total_discount_amount' => 0,
+                        'total_tax_amount' => 0,
+                        'type' => 'physical',
+                        'unit_price' => 1000,
+                    ]
+                ],
+                'selected_shipping_option' => [
+                    'id' => 'flatrate_flatrate',
+                    'price' => 500,
+                    'tax_amount' => 0,
+                    'tax_rate' => 0,
+                ],
+                'order_amount' => 1500,
+                'status' => 'checkout_complete',
+            ]);
+
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'order_id' => $klarnaOrderId,
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->any())->method('updateMerchantReferences')
+            ->willReturn([]);
+        $this->orderManagementMock->expects($this->any())->method('acknowledgeOrder')
+            ->willReturn(['is_successful' => true]);
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '1',
+            ],
+            [
+                'state' => 'processing',
+                'status' => 'processing',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Kustom Checkout',
+                    'klarna_reference' => '12345',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoConfigFixture current_store general/region/state_required ''
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldNotCreateOrderWhenCartIsLocked(): void
+    {
+        $expectedResponse = '{"error":"The cart is locked for processing. Please try again later."}';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        // MTF overrides lockers with a dummy so this is one way to trigger lock error
+        $lockManagerMock = $this->createMock(LockManagerInterface::class);
+        $cartMutex = $this->_objectManager->create(CartMutex::class, ['lockManager' => $lockManagerMock]);
+        $this->_objectManager->addSharedInstance($cartMutex, CartMutex::class);
+        $quoteManagement = $this->_objectManager->create(QuoteManagement::class, [
+            'cartMutex' => $cartMutex,
+        ]);
+        $this->_objectManager->addSharedInstance($quoteManagement, QuoteManagement::class);
+        $lockManagerMock->expects($this->any())->method('lock')->willReturn(false);
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'billing_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'shipping_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'order_id' => $klarnaOrderId,
+                'is_successful' => true,
+                'order_lines' => [
+                    [
+                        'image_url' => '',
+                        'name' => 'Simple Product',
+                        'product_url' => 'http://localhost/index.php/simple-product.html',
+                        'quantity' => 1,
+                        'reference' => 'simple',
+                        'tax_rate' => 0,
+                        'total_amount' => 1000,
+                        'total_discount_amount' => 0,
+                        'total_tax_amount' => 0,
+                        'type' => 'physical',
+                        'unit_price' => 1000,
+                    ]
+                ],
+                'selected_shipping_option' => [
+                    'id' => 'flatrate_flatrate',
+                    'price' => 500,
+                    'tax_amount' => 0,
+                    'tax_rate' => 0,
+                ],
+                'order_amount' => 1500,
+                'status' => 'checkout_complete',
+            ]);
+
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'order_id' => $klarnaOrderId,
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->any())->method('updateMerchantReferences')
+            ->willReturn([]);
+        $this->orderManagementMock->expects($this->any())->method('acknowledgeOrder')
+            ->willReturn(['is_successful' => true]);
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     */
+    public function testExecuteShouldThrowAnErrorWhenIdMatchesNothing(): void
+    {
+        $expectedResponse = '{"error":"Failed to create order"}';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/klarna_order_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldNotCancelOrderDueToLocalizedException(): void
+    {
+        $expectedResponse = '{"error":"Failed to update order state"}';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'captured_amount' => 0,
+                'captures' => [],
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->any())->method('updateMerchantReferences')
+            ->willThrowException(new LocalizedException(__('Test error')));
+        $this->orderManagementMock->expects($this->never())->method('cancelOrder');
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldNotCancelOrderDueToLocalizedExceptionWhenCreatingOneWithCheckoutApiDetails(): void
+    {
+        $expectedResponse = '{"error":"Failed to create order"}';
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willThrowException(new LocalizedException(__('Test error')));
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'captured_amount' => 0,
+                'captures' => [],
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->never())->method('cancelOrder');
+
+        $this->getRequest()->setMethod(Http::METHOD_POST);
+        $this->dispatch('kco/api/push/id/' . $klarnaOrderId);
+        $this->assertEquals($expectedResponse, $this->getResponse()->getBody());
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+    }
+
+    /**
+     * @param string $klarnaOrderId
+     * @param mixed[] $expectedKlarnaOrder
+     * @param mixed[] $expectedOrder
+     * @param mixed[] $expectedPayment
+     *
+     * @return void
+     * @throws LocalizedException
+     */
+    private function assertOrderData(
+        string $klarnaOrderId,
+        array $expectedKlarnaOrder,
+        array $expectedOrder,
+        array $expectedPayment
+    ): void {
+        $klarnaOrder = $this->kOrderFactory->create()->load($klarnaOrderId, 'klarna_order_id');
+        if (!$expectedKlarnaOrder) {
+            $this->assertNull($klarnaOrder->getId(), 'Assert that order does not exist');
+
+            return;
+        }
+
+        $klarnaOrderData = array_intersect_key($klarnaOrder->getData(), $expectedKlarnaOrder);
+        $this->assertEquals($expectedKlarnaOrder, $klarnaOrderData);
+
+        $magentoOrder = $this->mOrderFactory->create()->load($klarnaOrder->getOrderId());
+        $magentoOrderData = array_intersect_key($magentoOrder->getData(), $expectedOrder);
+        $this->assertEquals($expectedOrder, $magentoOrderData);
+
+        $paymentData = $magentoOrder->getId() ? $magentoOrder->getPayment()->getData() : [];
+        $paymentData = array_intersect_key($paymentData, $expectedPayment);
+        $this->assertEquals($expectedPayment, $paymentData);
+    }
+}
diff --git a/Test/Integration/Controller/Klarna/ConfirmationTest.php b/Test/Integration/Controller/Klarna/ConfirmationTest.php
new file mode 100644
index 0000000..501479f
--- /dev/null
+++ b/Test/Integration/Controller/Klarna/ConfirmationTest.php
@@ -0,0 +1,473 @@
+<?php
+
+/**
+ * Copyright © Klarna Bank AB (publ)
+ *
+ * For the full copyright and license information, please view the NOTICE
+ * and LICENSE files that were distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace Klarna\Kco\Test\Integration\Controller\Klarna;
+
+use Klarna\Backend\Model\Api\Rest\Service\Ordermanagement;
+use Klarna\Base\Exception;
+use Klarna\Base\Model\OrderFactory as KlarnaOrderFactory;
+use Klarna\Kco\Model\Api\Rest\Service\Checkout;
+use Magento\Framework\App\Request\Http;
+use Magento\Framework\Exception\LocalizedException;
+use Magento\Framework\Lock\LockManagerInterface;
+use Magento\Quote\Model\CartMutex;
+use Magento\Quote\Model\QuoteManagement;
+use Magento\Sales\Model\OrderFactory as MagentoOrderFactory;
+use Magento\TestFramework\TestCase\AbstractController;
+use PHPUnit\Framework\MockObject\MockObject;
+
+class ConfirmationTest extends AbstractController
+{
+    /**
+     * @var KlarnaOrderFactory
+     */
+    private $kOrderFactory;
+
+    /**
+     * @var MagentoOrderFactory
+     */
+    private $mOrderFactory;
+
+    /**
+     * @var Checkout|MockObject
+     */
+    private $checkoutMock;
+
+    /**
+     * @var Ordermanagement|MockObject
+     */
+    private $orderManagementMock;
+
+    /**
+     * @inheritDoc
+     */
+    protected function setUp(): void
+    {
+        parent::setUp();
+
+        $this->kOrderFactory = $this->_objectManager->create(KlarnaOrderFactory::class);
+        $this->mOrderFactory = $this->_objectManager->create(MagentoOrderFactory::class);
+        $this->checkoutMock = $this->createMock(Checkout::class);
+        $this->_objectManager->addSharedInstance($this->checkoutMock, Checkout::class);
+        $this->orderManagementMock = $this->createMock(Ordermanagement::class);
+        $this->_objectManager->addSharedInstance($this->orderManagementMock, Ordermanagement::class);
+    }
+
+    /**
+     * @magentoAppArea frontend
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoConfigFixture current_store klarna/api/debug 1
+     * @magentoConfigFixture current_store general/region/state_required ''
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldSuccessfullyCreateOrderByCheckoutApiResponse(): void
+    {
+        $expectedRedirect = 'checkout/klarna/success';
+        $expectedMessages = [];
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'billing_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'shipping_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'order_id' => $klarnaOrderId,
+                'is_successful' => true,
+                'order_lines' => [
+                    [
+                        'image_url' => '',
+                        'name' => 'Simple Product',
+                        'product_url' => 'http://localhost/index.php/simple-product.html',
+                        'quantity' => 1,
+                        'reference' => 'simple',
+                        'tax_rate' => 0,
+                        'total_amount' => 1000,
+                        'total_discount_amount' => 0,
+                        'total_tax_amount' => 0,
+                        'type' => 'physical',
+                        'unit_price' => 1000,
+                    ]
+                ],
+                'selected_shipping_option' => [
+                    'id' => 'flatrate_flatrate',
+                    'price' => 500,
+                    'tax_amount' => 0,
+                    'tax_rate' => 0,
+                ],
+                'order_amount' => 1500,
+                'status' => 'checkout_complete',
+            ]);
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/' . $klarnaOrderId);
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'processing',
+                'status' => 'processing',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Kustom Checkout',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoConfigFixture current_store general/region/state_required ''
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldJustRedirectUserToSuccessPageWhenCartIsLocked(): void
+    {
+        $expectedRedirect = 'checkout/klarna/success';
+        $expectedMessages = [];
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        // MTF overrides lockers with a dummy so this is one way to trigger lock error
+        $lockManagerMock = $this->createMock(LockManagerInterface::class);
+        $cartMutex = $this->_objectManager->create(CartMutex::class, ['lockManager' => $lockManagerMock]);
+        $this->_objectManager->addSharedInstance($cartMutex, CartMutex::class);
+        $quoteManagement = $this->_objectManager->create(QuoteManagement::class, [
+            'cartMutex' => $cartMutex,
+        ]);
+        $this->_objectManager->addSharedInstance($quoteManagement, QuoteManagement::class);
+        $lockManagerMock->expects($this->any())->method('lock')->willReturn(false);
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'billing_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'shipping_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'order_id' => $klarnaOrderId,
+                'is_successful' => true,
+                'order_lines' => [
+                    [
+                        'image_url' => '',
+                        'name' => 'Simple Product',
+                        'product_url' => 'http://localhost/index.php/simple-product.html',
+                        'quantity' => 1,
+                        'reference' => 'simple',
+                        'tax_rate' => 0,
+                        'total_amount' => 1000,
+                        'total_discount_amount' => 0,
+                        'total_tax_amount' => 0,
+                        'type' => 'physical',
+                        'unit_price' => 1000,
+                    ]
+                ],
+                'selected_shipping_option' => [
+                    'id' => 'flatrate_flatrate',
+                    'price' => 500,
+                    'tax_amount' => 0,
+                    'tax_rate' => 0,
+                ],
+                'order_amount' => 1500,
+                'status' => 'checkout_complete',
+            ]);
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/' . $klarnaOrderId);
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/klarna_order_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldJustRedirectUserToSuccessPageWhenOrderAlreadyExists(): void
+    {
+        $expectedRedirect = 'checkout/klarna/success';
+        $expectedMessages = [];
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'billing_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'shipping_address' => [
+                    'city' => 'City',
+                    'country' => 'US',
+                    'email' => 'customer@example.com',
+                    'family_name' => 'Lastname',
+                    'given_name' => 'Firstname',
+                    'phone' => '040123456',
+                    'postal_code' => '12345',
+                    'street_address' => 'Street',
+                    'region' => 'California',
+                ],
+                'order_id' => $klarnaOrderId,
+                'is_successful' => true,
+                'order_lines' => [
+                    [
+                        'image_url' => '',
+                        'name' => 'Simple Product',
+                        'product_url' => 'http://localhost/index.php/simple-product.html',
+                        'quantity' => 1,
+                        'reference' => 'simple',
+                        'tax_rate' => 0,
+                        'total_amount' => 1000,
+                        'total_discount_amount' => 0,
+                        'total_tax_amount' => 0,
+                        'type' => 'physical',
+                        'unit_price' => 1000,
+                    ]
+                ],
+                'selected_shipping_option' => [
+                    'id' => 'flatrate_flatrate',
+                    'price' => 500,
+                    'tax_amount' => 0,
+                    'tax_rate' => 0,
+                ],
+                'order_amount' => 1500,
+                'status' => 'checkout_complete',
+            ]);
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/' . $klarnaOrderId);
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [
+                'klarna_order_id' => $klarnaOrderId,
+                'is_acknowledged' => '0',
+            ],
+            [
+                'state' => 'new',
+                'status' => 'pending',
+                'increment_id' => '100000001',
+            ],
+            [
+                'additional_information' => [
+                    'method_title' => 'Check / Money order',
+                ],
+            ]
+        );
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     */
+    public function testExecuteShouldThrowAnErrorWhenIdMatchesNothing(): void
+    {
+        $expectedRedirect = 'checkout/cart';
+        $expectedMessages = ['No Kustom Kco quote could be found with the provided Kustom order id: 123456-1234-1234-1234-1234567890'];
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/' . $klarnaOrderId);
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     */
+    public function testExecuteShouldThrowAnErrorWhenNoIdIsGiven(): void
+    {
+        $expectedRedirect = 'checkout/cart';
+        $expectedMessages = ['Unable to process order. Please try again'];
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/');
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+    }
+
+    /**
+     * @magentoAppIsolation enabled
+     * @magentoDbIsolation enabled
+     * @magentoConfigFixture current_store payment/klarna_kco/active 1
+     * @magentoDataFixture Klarna_Base::Test/Integration/_files/fixtures/quote_setup1_single_simple_product.php
+     */
+    public function testExecuteShouldNotCancelOrderDueToLocalizedException(): void
+    {
+        $expectedRedirect = 'checkout/cart';
+        $expectedMessages = ['Test error'];
+        $klarnaOrderId = '123456-1234-1234-1234-1234567890';
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+
+        $this->checkoutMock->expects($this->any())->method('getOrder')
+            ->willThrowException(new LocalizedException(__('Test error')));
+        $this->orderManagementMock->expects($this->any())->method('getOrder')
+            ->willReturn([
+                'captured_amount' => 0,
+                'captures' => [],
+                'klarna_reference' => '12345',
+            ]);
+        $this->orderManagementMock->expects($this->never())->method('cancelOrder');
+
+        $this->getRequest()->setMethod(Http::METHOD_GET);
+        $this->dispatch('checkout/klarna/confirmation/id/' . $klarnaOrderId);
+        $this->assertRedirect($this->stringContains($expectedRedirect));
+        $this->assertSessionMessages($this->equalTo($expectedMessages));
+
+        $this->assertOrderData(
+            $klarnaOrderId,
+            [],
+            [],
+            []
+        );
+    }
+
+    /**
+     * @param string $klarnaOrderId
+     * @param mixed[] $expectedKlarnaOrder
+     * @param mixed[] $expectedOrder
+     * @param mixed[] $expectedPayment
+     *
+     * @return void
+     * @throws LocalizedException
+     */
+    private function assertOrderData(
+        string $klarnaOrderId,
+        array $expectedKlarnaOrder,
+        array $expectedOrder,
+        array $expectedPayment
+    ): void {
+        $klarnaOrder = $this->kOrderFactory->create()->load($klarnaOrderId, 'klarna_order_id');
+        if (!$expectedKlarnaOrder) {
+            $this->assertNull($klarnaOrder->getId(), 'Assert that order does not exist');
+
+            return;
+        }
+
+        $klarnaOrderData = array_intersect_key($klarnaOrder->getData(), $expectedKlarnaOrder);
+        $this->assertEquals($expectedKlarnaOrder, $klarnaOrderData);
+
+        $magentoOrder = $this->mOrderFactory->create()->load($klarnaOrder->getOrderId());
+        $magentoOrderData = array_intersect_key($magentoOrder->getData(), $expectedOrder);
+        $this->assertEquals($expectedOrder, $magentoOrderData);
+
+        $paymentData = $magentoOrder->getId() ? $magentoOrder->getPayment()->getData() : [];
+        $paymentData = array_intersect_key($paymentData, $expectedPayment);
+        $this->assertEquals($expectedPayment, $paymentData);
+    }
+}
diff --git a/Test/Unit/Model/Cart/FullUpdateTest.php b/Test/Unit/Model/Cart/FullUpdateTest.php
index a646471..0877f62 100644
--- a/Test/Unit/Model/Cart/FullUpdateTest.php
+++ b/Test/Unit/Model/Cart/FullUpdateTest.php
@@ -6,7 +6,7 @@
  * and LICENSE files that were distributed with this source code.
  */
 
-namespace Klarna\Kco\Test\Unit\Model\Checkout;
+namespace Klarna\Kco\Test\Unit\Model\Cart;
 
 use Klarna\Kco\Model\Cart\FullUpdate;
 use Klarna\Base\Test\Unit\Mock\MockFactory;
@@ -112,7 +112,12 @@ protected function setUp(): void
         $this->quote->method('getShippingAddress')
             ->willReturn($quoteShippingAddress);
 
-        $extensionAttributes = $this->mockFactory->create(CartExtension::class, [], ['getShippingAssignments']);
+        if (method_exists(CartExtension::class, 'getShippingAssignments')) {
+            $extensionAttributes = $this->mockFactory->create(CartExtension::class, ['getShippingAssignments']);
+        } else {
+            $extensionAttributes = $this->mockFactory->create(CartExtension::class, [], ['getShippingAssignments']);
+        }
+
         $extensionAttributes->method('getShippingAssignments')
             ->willReturn([]);