diff --git a/app/code/Magento/Sales/Controller/Adminhtml/Order/Creditmemo/Save.php b/app/code/Magento/Sales/Controller/Adminhtml/Order/Creditmemo/Save.php
index e55d1e6bfe869..33f1b07e4d567 100644
--- a/app/code/Magento/Sales/Controller/Adminhtml/Order/Creditmemo/Save.php
+++ b/app/code/Magento/Sales/Controller/Adminhtml/Order/Creditmemo/Save.php
@@ -102,7 +102,7 @@ public function execute()
                 $creditmemoManagement = $this->_objectManager->create(
                     \Magento\Sales\Api\CreditmemoManagementInterface::class
                 );
-                $creditmemoManagement->refund($creditmemo, (bool)$data['do_offline'], !empty($data['send_email']));
+                $creditmemoManagement->refund($creditmemo, (bool)$data['do_offline']);
 
                 if (!empty($data['send_email'])) {
                     $this->creditmemoSender->send($creditmemo);
diff --git a/app/code/Magento/Sales/Model/Order/Creditmemo/RefundOperation.php b/app/code/Magento/Sales/Model/Order/Creditmemo/RefundOperation.php
new file mode 100644
index 0000000000000..ef60ad2ce51be
--- /dev/null
+++ b/app/code/Magento/Sales/Model/Order/Creditmemo/RefundOperation.php
@@ -0,0 +1,126 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Sales\Model\Order\Creditmemo;
+
+use Magento\Sales\Api\Data\CreditmemoInterface;
+use Magento\Sales\Api\Data\OrderInterface;
+use Magento\Sales\Model\Order\Creditmemo;
+
+class RefundOperation
+{
+    /**
+     * @var \Magento\Framework\Event\ManagerInterface
+     */
+    private $eventManager;
+
+    /**
+     * @var \Magento\Framework\Pricing\PriceCurrencyInterface
+     */
+    private $priceCurrency;
+
+    /**
+     * @param \Magento\Framework\Model\Context $context
+     * @param \Magento\Framework\Pricing\PriceCurrencyInterface $priceCurrency
+     */
+    public function __construct(
+        \Magento\Framework\Model\Context $context,
+        \Magento\Framework\Pricing\PriceCurrencyInterface $priceCurrency
+    ) {
+        $this->eventManager = $context->getEventDispatcher();
+        $this->priceCurrency = $priceCurrency;
+    }
+
+    /**
+     * @param CreditmemoInterface $creditmemo
+     * @param OrderInterface $order
+     * @param bool $online
+     * @return OrderInterface
+     */
+    public function execute(CreditmemoInterface $creditmemo, OrderInterface $order, $online = false)
+    {
+        if ($creditmemo->getState() == Creditmemo::STATE_REFUNDED
+            && $creditmemo->getOrderId() == $order->getEntityId()
+        ) {
+            foreach ($creditmemo->getItems() as $item) {
+                if ($item->isDeleted()) {
+                    continue;
+                }
+                $item->setCreditMemo($creditmemo);
+                if ($item->getQty() > 0) {
+                    $item->register();
+                } else {
+                    $item->isDeleted(true);
+                }
+            }
+
+            $baseOrderRefund = $this->priceCurrency->round(
+                $order->getBaseTotalRefunded() + $creditmemo->getBaseGrandTotal()
+            );
+            $orderRefund = $this->priceCurrency->round(
+                $order->getTotalRefunded() + $creditmemo->getGrandTotal()
+            );
+            $order->setBaseTotalRefunded($baseOrderRefund);
+            $order->setTotalRefunded($orderRefund);
+
+            $order->setBaseSubtotalRefunded($order->getBaseSubtotalRefunded() + $creditmemo->getBaseSubtotal());
+            $order->setSubtotalRefunded($order->getSubtotalRefunded() + $creditmemo->getSubtotal());
+
+            $order->setBaseTaxRefunded($order->getBaseTaxRefunded() + $creditmemo->getBaseTaxAmount());
+            $order->setTaxRefunded($order->getTaxRefunded() + $creditmemo->getTaxAmount());
+            $order->setBaseDiscountTaxCompensationRefunded(
+                $order->getBaseDiscountTaxCompensationRefunded() + $creditmemo->getBaseDiscountTaxCompensationAmount()
+            );
+            $order->setDiscountTaxCompensationRefunded(
+                $order->getDiscountTaxCompensationRefunded() + $creditmemo->getDiscountTaxCompensationAmount()
+            );
+
+            $order->setBaseShippingRefunded($order->getBaseShippingRefunded() + $creditmemo->getBaseShippingAmount());
+            $order->setShippingRefunded($order->getShippingRefunded() + $creditmemo->getShippingAmount());
+
+            $order->setBaseShippingTaxRefunded(
+                $order->getBaseShippingTaxRefunded() + $creditmemo->getBaseShippingTaxAmount()
+            );
+            $order->setShippingTaxRefunded($order->getShippingTaxRefunded() + $creditmemo->getShippingTaxAmount());
+
+            $order->setAdjustmentPositive($order->getAdjustmentPositive() + $creditmemo->getAdjustmentPositive());
+            $order->setBaseAdjustmentPositive(
+                $order->getBaseAdjustmentPositive() + $creditmemo->getBaseAdjustmentPositive()
+            );
+
+            $order->setAdjustmentNegative($order->getAdjustmentNegative() + $creditmemo->getAdjustmentNegative());
+            $order->setBaseAdjustmentNegative(
+                $order->getBaseAdjustmentNegative() + $creditmemo->getBaseAdjustmentNegative()
+            );
+
+            $order->setDiscountRefunded($order->getDiscountRefunded() + $creditmemo->getDiscountAmount());
+            $order->setBaseDiscountRefunded($order->getBaseDiscountRefunded() + $creditmemo->getBaseDiscountAmount());
+
+            if ($online) {
+                $order->setTotalOnlineRefunded($order->getTotalOnlineRefunded() + $creditmemo->getGrandTotal());
+                $order->setBaseTotalOnlineRefunded(
+                    $order->getBaseTotalOnlineRefunded() + $creditmemo->getBaseGrandTotal()
+                );
+            } else {
+                $order->setTotalOfflineRefunded($order->getTotalOfflineRefunded() + $creditmemo->getGrandTotal());
+                $order->setBaseTotalOfflineRefunded(
+                    $order->getBaseTotalOfflineRefunded() + $creditmemo->getBaseGrandTotal()
+                );
+            }
+
+            $order->setBaseTotalInvoicedCost(
+                $order->getBaseTotalInvoicedCost() - $creditmemo->getBaseCost()
+            );
+
+            if ($online) {
+                $order->getPayment()->refund($creditmemo);
+            }
+
+            $this->eventManager->dispatch('sales_order_creditmemo_refund', ['creditmemo' => $creditmemo]);
+        }
+
+        return $order;
+    }
+}
diff --git a/app/code/Magento/Sales/Model/Order/PaymentAdapter.php b/app/code/Magento/Sales/Model/Order/PaymentAdapter.php
index 84eb0fa07553c..d176ce0566bb3 100644
--- a/app/code/Magento/Sales/Model/Order/PaymentAdapter.php
+++ b/app/code/Magento/Sales/Model/Order/PaymentAdapter.php
@@ -12,20 +12,40 @@
  */
 class PaymentAdapter implements PaymentAdapterInterface
 {
+    /**
+     * @var \Magento\Sales\Model\Order\Creditmemo\RefundOperation
+     */
+    private $refundOperation;
+
     /**
      * @var \Magento\Sales\Model\Order\Invoice\PayOperation
      */
     private $payOperation;
 
     /**
+     * PaymentAdapter constructor.
+     * @param \Magento\Sales\Model\Order\Creditmemo\RefundOperation $refundOperation
      * @param \Magento\Sales\Model\Order\Invoice\PayOperation $payOperation
      */
     public function __construct(
+        \Magento\Sales\Model\Order\Creditmemo\RefundOperation $refundOperation,
         \Magento\Sales\Model\Order\Invoice\PayOperation $payOperation
     ) {
+        $this->refundOperation = $refundOperation;
         $this->payOperation = $payOperation;
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function refund(
+        \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo,
+        \Magento\Sales\Api\Data\OrderInterface $order,
+        $isOnline = false
+    ) {
+        return $this->refundOperation->execute($creditmemo, $order, $isOnline);
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/app/code/Magento/Sales/Model/Order/PaymentAdapterInterface.php b/app/code/Magento/Sales/Model/Order/PaymentAdapterInterface.php
index 0e4b193169da8..3636bc2592f3b 100644
--- a/app/code/Magento/Sales/Model/Order/PaymentAdapterInterface.php
+++ b/app/code/Magento/Sales/Model/Order/PaymentAdapterInterface.php
@@ -23,4 +23,16 @@ interface PaymentAdapterInterface
      * @return OrderInterface
      */
     public function pay(OrderInterface $order, InvoiceInterface $invoice, $capture);
+
+    /**
+     * @param \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo
+     * @param \Magento\Sales\Api\Data\OrderInterface $order
+     * @param bool $isOnline
+     * @return \Magento\Sales\Api\Data\OrderInterface
+     */
+    public function refund(
+        \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo,
+        \Magento\Sales\Api\Data\OrderInterface $order,
+        $isOnline = false
+    );
 }
diff --git a/app/code/Magento/Sales/Model/ResourceModel/Order/Creditmemo/Relation/Refund.php b/app/code/Magento/Sales/Model/ResourceModel/Order/Creditmemo/Relation/Refund.php
index 6c38259432780..82df0aa0bebdf 100644
--- a/app/code/Magento/Sales/Model/ResourceModel/Order/Creditmemo/Relation/Refund.php
+++ b/app/code/Magento/Sales/Model/ResourceModel/Order/Creditmemo/Relation/Refund.php
@@ -10,6 +10,7 @@
 
 /**
  * Class Relation
+ * @deprecated
  */
 class Refund implements RelationInterface
 {
diff --git a/app/code/Magento/Sales/Model/Service/CreditmemoService.php b/app/code/Magento/Sales/Model/Service/CreditmemoService.php
index 54bb5a746e51f..4889ccd3750d5 100644
--- a/app/code/Magento/Sales/Model/Service/CreditmemoService.php
+++ b/app/code/Magento/Sales/Model/Service/CreditmemoService.php
@@ -8,6 +8,7 @@
 
 /**
  * Class CreditmemoService
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class CreditmemoService implements \Magento\Sales\Api\CreditmemoManagementInterface
 {
@@ -46,6 +47,26 @@ class CreditmemoService implements \Magento\Sales\Api\CreditmemoManagementInterf
      */
     protected $eventManager;
 
+    /**
+     * @var \Magento\Framework\App\ResourceConnection
+     */
+    private $resource;
+
+    /**
+     * @var \Magento\Sales\Model\Order\PaymentAdapterInterface
+     */
+    private $paymentAdapter;
+
+    /**
+     * @var \Magento\Sales\Api\OrderRepositoryInterface
+     */
+    private $orderRepository;
+
+    /**
+     * @var \Magento\Sales\Api\InvoiceRepositoryInterface
+     */
+    private $invoiceRepository;
+
     /**
      * @param \Magento\Sales\Api\CreditmemoRepositoryInterface $creditmemoRepository
      * @param \Magento\Sales\Api\CreditmemoCommentRepositoryInterface $creditmemoCommentRepository
@@ -130,6 +151,7 @@ public function notify($id)
      * @param \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo
      * @param bool $offlineRequested
      * @return \Magento\Sales\Api\Data\CreditmemoInterface
+     * @throws \Magento\Framework\Exception\LocalizedException
      */
     public function refund(
         \Magento\Sales\Api\Data\CreditmemoInterface $creditmemo,
@@ -138,19 +160,31 @@ public function refund(
         $this->validateForRefund($creditmemo);
         $creditmemo->setState(\Magento\Sales\Model\Order\Creditmemo::STATE_REFUNDED);
 
-        foreach ($creditmemo->getAllItems() as $item) {
-            $item->setCreditMemo($creditmemo);
-            if ($item->getQty() > 0) {
-                $item->register();
-            } else {
-                $item->isDeleted(true);
+        $connection = $this->getResource()->getConnection('sales');
+        $connection->beginTransaction();
+        try {
+            $order = $this->getPaymentAdapter()->refund(
+                $creditmemo,
+                $creditmemo->getOrder(),
+                !$offlineRequested
+            );
+            $this->getOrderRepository()->save($order);
+            $invoice = $creditmemo->getInvoice();
+            if ($invoice && !$offlineRequested) {
+                $invoice->setIsUsedForRefund(true);
+                $invoice->setBaseTotalRefunded(
+                    $invoice->getBaseTotalRefunded() + $creditmemo->getBaseGrandTotal()
+                );
+                $creditmemo->setInvoiceId($invoice->getId());
+                $this->getInvoiceRepository()->save($creditmemo->getInvoice());
             }
+            $this->creditmemoRepository->save($creditmemo);
+            $connection->commit();
+        } catch (\Exception $e) {
+            $connection->rollBack();
+            throw new \Magento\Framework\Exception\LocalizedException($e->getMessage());
         }
 
-        $creditmemo->setDoTransaction(!$offlineRequested);
-
-        $this->eventManager->dispatch('sales_order_creditmemo_refund', ['creditmemo' => $creditmemo]);
-        $this->creditmemoRepository->save($creditmemo);
         return $creditmemo;
     }
 
@@ -183,4 +217,60 @@ protected function validateForRefund(\Magento\Sales\Api\Data\CreditmemoInterface
         }
         return true;
     }
+
+    /**
+     * @return \Magento\Sales\Model\Order\PaymentAdapterInterface
+     *
+     * @deprecated
+     */
+    private function getPaymentAdapter()
+    {
+        if ($this->paymentAdapter === null) {
+            $this->paymentAdapter = \Magento\Framework\App\ObjectManager::getInstance()
+                ->get(\Magento\Sales\Model\Order\PaymentAdapterInterface::class);
+        }
+        return $this->paymentAdapter;
+    }
+
+    /**
+     * @return \Magento\Framework\App\ResourceConnection|mixed
+     *
+     * @deprecated
+     */
+    private function getResource()
+    {
+        if ($this->resource === null) {
+            $this->resource = \Magento\Framework\App\ObjectManager::getInstance()
+                ->get(\Magento\Framework\App\ResourceConnection::class);
+        }
+        return $this->resource;
+    }
+
+    /**
+     * @return \Magento\Sales\Api\OrderRepositoryInterface
+     *
+     * @deprecated
+     */
+    private function getOrderRepository()
+    {
+        if ($this->orderRepository === null) {
+            $this->orderRepository = \Magento\Framework\App\ObjectManager::getInstance()
+                ->get(\Magento\Sales\Api\OrderRepositoryInterface::class);
+        }
+        return $this->orderRepository;
+    }
+
+    /**
+     * @return \Magento\Sales\Api\InvoiceRepositoryInterface
+     *
+     * @deprecated
+     */
+    private function getInvoiceRepository()
+    {
+        if ($this->invoiceRepository === null) {
+            $this->invoiceRepository = \Magento\Framework\App\ObjectManager::getInstance()
+                ->get(\Magento\Sales\Api\InvoiceRepositoryInterface::class);
+        }
+        return $this->invoiceRepository;
+    }
 }
diff --git a/app/code/Magento/Sales/Test/Unit/Model/Order/Creditmemo/RefundOperationTest.php b/app/code/Magento/Sales/Test/Unit/Model/Order/Creditmemo/RefundOperationTest.php
new file mode 100644
index 0000000000000..93caeba8643f1
--- /dev/null
+++ b/app/code/Magento/Sales/Test/Unit/Model/Order/Creditmemo/RefundOperationTest.php
@@ -0,0 +1,398 @@
+<?php
+/**
+ * Copyright © 2016 Magento. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+namespace Magento\Sales\Test\Unit\Model\Order\Creditmemo;
+
+use Magento\Sales\Model\Order\Creditmemo;
+
+/**
+ * Unit test for refund operation.
+ */
+class RefundOperationTest extends \PHPUnit_Framework_TestCase
+{
+    /**
+     * @var \Magento\Sales\Model\Order\Creditmemo\RefundOperation
+     */
+    private $subject;
+
+    /**
+     * @var \Magento\Sales\Api\Data\OrderInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $orderMock;
+
+    /**
+     * @var \Magento\Sales\Api\Data\CreditmemoInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $creditmemoMock;
+
+    /**
+     * @var \Magento\Sales\Api\Data\OrderPaymentInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $paymentMock;
+
+    /**
+     * @var \Magento\Framework\Pricing\PriceCurrencyInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $priceCurrencyMock;
+
+    /**
+     * @var \Magento\Framework\Event\ManagerInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $eventManagerMock;
+
+    protected function setUp()
+    {
+        $this->orderMock = $this->getMockBuilder(\Magento\Sales\Api\Data\OrderInterface::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+
+        $this->creditmemoMock = $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['getBaseCost'])
+            ->getMockForAbstractClass();
+
+        $this->paymentMock = $this->getMockBuilder(\Magento\Framework\Pricing\PriceCurrencyInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['refund'])
+            ->getMockForAbstractClass();
+
+        $this->priceCurrencyMock = $this->getMockBuilder(\Magento\Framework\Pricing\PriceCurrencyInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['round'])
+            ->getMockForAbstractClass();
+
+        $contextMock = $this->getMockBuilder(\Magento\Framework\Model\Context::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['getEventDispatcher'])
+            ->getMock();
+
+        $this->eventManagerMock = $this->getMockBuilder(\Magento\Framework\Event\ManagerInterface::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
+        $contextMock->expects($this->once())
+            ->method('getEventDispatcher')
+            ->willReturn($this->eventManagerMock);
+
+        $this->subject = new \Magento\Sales\Model\Order\Creditmemo\RefundOperation(
+            $contextMock,
+            $this->priceCurrencyMock
+        );
+    }
+
+    /**
+     * @param string $state
+     * @dataProvider  executeNotRefundedCreditmemoDataProvider
+     */
+    public function testExecuteNotRefundedCreditmemo($state)
+    {
+        $this->creditmemoMock->expects($this->once())
+            ->method('getState')
+            ->willReturn($state);
+        $this->orderMock->expects($this->never())
+            ->method('getEntityId');
+        $this->assertEquals(
+            $this->orderMock,
+            $this->subject->execute(
+                $this->creditmemoMock,
+                $this->orderMock
+            )
+        );
+    }
+
+    /**
+     * Data provider for testExecuteNotRefundedCreditmemo
+     * @return array
+     */
+    public function executeNotRefundedCreditmemoDataProvider()
+    {
+        return [
+            [Creditmemo::STATE_OPEN],
+            [Creditmemo::STATE_CANCELED],
+        ];
+    }
+
+    public function testExecuteWithWrongOrder()
+    {
+        $creditmemoOrderId = 1;
+        $orderId = 2;
+        $this->creditmemoMock->expects($this->once())
+            ->method('getState')
+            ->willReturn(Creditmemo::STATE_REFUNDED);
+        $this->creditmemoMock->expects($this->once())
+            ->method('getOrderId')
+            ->willReturn($creditmemoOrderId);
+        $this->orderMock->expects($this->once())
+            ->method('getEntityId')
+            ->willReturn($orderId);
+        $this->orderMock->expects($this->never())
+            ->method('setTotalRefunded');
+        $this->assertEquals(
+            $this->orderMock,
+            $this->subject->execute($this->creditmemoMock, $this->orderMock)
+        );
+    }
+
+    /**
+     * @param array $amounts
+     * @dataProvider baseAmountsDataProvider
+     */
+    public function testExecuteOffline($amounts)
+    {
+        $orderId = 1;
+        $this->creditmemoMock->expects($this->once())
+            ->method('getState')
+            ->willReturn(Creditmemo::STATE_REFUNDED);
+        $this->creditmemoMock->expects($this->once())
+            ->method('getOrderId')
+            ->willReturn($orderId);
+        $this->orderMock->expects($this->once())
+            ->method('getEntityId')
+            ->willReturn($orderId);
+
+        $this->registerItems();
+
+        $this->priceCurrencyMock->expects($this->any())
+            ->method('round')
+            ->willReturnArgument(0);
+
+        $this->setBaseAmounts($amounts);
+        $this->orderMock->expects($this->once())
+            ->method('setTotalOfflineRefunded')
+            ->with(2);
+        $this->orderMock->expects($this->once())
+            ->method('getTotalOfflineRefunded')
+            ->willReturn(0);
+        $this->orderMock->expects($this->once())
+            ->method('setBaseTotalOfflineRefunded')
+            ->with(1);
+        $this->orderMock->expects($this->once())
+            ->method('getBaseTotalOfflineRefunded')
+            ->willReturn(0);
+        $this->orderMock->expects($this->never())
+            ->method('setTotalOnlineRefunded');
+
+        $this->orderMock->expects($this->never())
+            ->method('getPayment');
+
+        $this->eventManagerMock->expects($this->once())
+            ->method('dispatch')
+            ->with(
+                'sales_order_creditmemo_refund',
+                ['creditmemo' => $this->creditmemoMock]
+            );
+
+        $this->assertEquals(
+            $this->orderMock,
+            $this->subject->execute($this->creditmemoMock, $this->orderMock, false)
+        );
+    }
+
+    /**
+     * @param array $amounts
+     * @dataProvider baseAmountsDataProvider
+     */
+    public function testExecuteOnline($amounts)
+    {
+        $orderId = 1;
+        $this->creditmemoMock->expects($this->once())
+            ->method('getState')
+            ->willReturn(Creditmemo::STATE_REFUNDED);
+        $this->creditmemoMock->expects($this->once())
+            ->method('getOrderId')
+            ->willReturn($orderId);
+        $this->orderMock->expects($this->once())
+            ->method('getEntityId')
+            ->willReturn($orderId);
+
+        $this->registerItems();
+
+        $this->priceCurrencyMock->expects($this->any())
+            ->method('round')
+            ->willReturnArgument(0);
+
+        $this->setBaseAmounts($amounts);
+        $this->orderMock->expects($this->once())
+            ->method('setTotalOnlineRefunded')
+            ->with(2);
+        $this->orderMock->expects($this->once())
+            ->method('getTotalOnlineRefunded')
+            ->willReturn(0);
+        $this->orderMock->expects($this->once())
+            ->method('setBaseTotalOnlineRefunded')
+            ->with(1);
+        $this->orderMock->expects($this->once())
+            ->method('getBaseTotalOnlineRefunded')
+            ->willReturn(0);
+        $this->orderMock->expects($this->never())
+            ->method('setTotalOfflineRefunded');
+
+        $this->orderMock->expects($this->once())
+            ->method('getPayment')
+            ->willReturn($this->paymentMock);
+        $this->paymentMock->expects($this->once())
+            ->method('refund')
+            ->with($this->creditmemoMock);
+
+        $this->assertEquals(
+            $this->orderMock,
+            $this->subject->execute($this->creditmemoMock, $this->orderMock, true)
+        );
+    }
+
+    /**
+     * @return array
+     * @SuppressWarnings(PHPMD.ExcessiveMethodLength)
+     */
+    public function baseAmountsDataProvider()
+    {
+        return [
+            [[
+                'setBaseTotalRefunded' => [
+                    'result' => 2,
+                    'order' => ['method' => 'getBaseTotalRefunded', 'amount' => 1],
+                    'creditmemo' => ['method' => 'getBaseGrandTotal', 'amount' => 1]
+                ],
+                'setTotalRefunded' => [
+                    'result' => 4,
+                    'order' => ['method' => 'getTotalRefunded', 'amount' => 2],
+                    'creditmemo' => ['method' => 'getGrandTotal', 'amount' => 2]
+                ],
+                'setBaseSubtotalRefunded' => [
+                    'result' => 6,
+                    'order' => ['method' => 'getBaseSubtotalRefunded', 'amount' => 3],
+                    'creditmemo' => ['method' => 'getBaseSubtotal', 'amount' => 3]
+                ],
+                'setSubtotalRefunded' => [
+                    'result' => 6,
+                    'order' => ['method' => 'getSubtotalRefunded', 'amount' => 3],
+                    'creditmemo' => ['method' => 'getSubtotal', 'amount' => 3]
+                ],
+                'setBaseTaxRefunded' => [
+                    'result' => 8,
+                    'order' => ['method' => 'getBaseTaxRefunded', 'amount' => 4],
+                    'creditmemo' => ['method' => 'getBaseTaxAmount', 'amount' => 4]
+                ],
+                'setTaxRefunded' => [
+                    'result' => 10,
+                    'order' => ['method' => 'getTaxRefunded', 'amount' => 5],
+                    'creditmemo' => ['method' => 'getTaxAmount', 'amount' => 5]
+                ],
+                'setBaseDiscountTaxCompensationRefunded' => [
+                    'result' => 12,
+                    'order' => ['method' => 'getBaseDiscountTaxCompensationRefunded', 'amount' => 6],
+                    'creditmemo' => ['method' => 'getBaseDiscountTaxCompensationAmount', 'amount' => 6]
+                ],
+                'setDiscountTaxCompensationRefunded' => [
+                    'result' => 14,
+                    'order' => ['method' => 'getDiscountTaxCompensationRefunded', 'amount' => 7],
+                    'creditmemo' => ['method' => 'getDiscountTaxCompensationAmount', 'amount' => 7]
+                ],
+                'setBaseShippingRefunded' => [
+                    'result' => 16,
+                    'order' => ['method' => 'getBaseShippingRefunded', 'amount' => 8],
+                    'creditmemo' => ['method' => 'getBaseShippingAmount', 'amount' => 8]
+                ],
+                'setShippingRefunded' => [
+                    'result' => 18,
+                    'order' => ['method' => 'getShippingRefunded', 'amount' => 9],
+                    'creditmemo' => ['method' => 'getShippingAmount', 'amount' => 9]
+                ],
+                'setBaseShippingTaxRefunded' => [
+                    'result' => 20,
+                    'order' => ['method' => 'getBaseShippingTaxRefunded', 'amount' => 10],
+                    'creditmemo' => ['method' => 'getBaseShippingTaxAmount', 'amount' => 10]
+                ],
+                'setShippingTaxRefunded' => [
+                    'result' => 22,
+                    'order' => ['method' => 'getShippingTaxRefunded', 'amount' => 11],
+                    'creditmemo' => ['method' => 'getShippingTaxAmount', 'amount' => 11]
+                ],
+                'setAdjustmentPositive' => [
+                    'result' => 24,
+                    'order' => ['method' => 'getAdjustmentPositive', 'amount' => 12],
+                    'creditmemo' => ['method' => 'getAdjustmentPositive', 'amount' => 12]
+                ],
+                'setBaseAdjustmentPositive' => [
+                    'result' => 26,
+                    'order' => ['method' => 'getBaseAdjustmentPositive', 'amount' => 13],
+                    'creditmemo' => ['method' => 'getBaseAdjustmentPositive', 'amount' => 13]
+                ],
+                'setAdjustmentNegative' => [
+                    'result' => 28,
+                    'order' => ['method' => 'getAdjustmentNegative', 'amount' => 14],
+                    'creditmemo' => ['method' => 'getAdjustmentNegative', 'amount' => 14]
+                ],
+                'setBaseAdjustmentNegative' => [
+                    'result' => 30,
+                    'order' => ['method' => 'getBaseAdjustmentNegative', 'amount' => 15],
+                    'creditmemo' => ['method' => 'getBaseAdjustmentNegative', 'amount' => 15]
+                ],
+                'setDiscountRefunded' => [
+                    'result' => 32,
+                    'order' => ['method' => 'getDiscountRefunded', 'amount' => 16],
+                    'creditmemo' => ['method' => 'getDiscountAmount', 'amount' => 16]
+                ],
+                'setBaseDiscountRefunded' => [
+                    'result' => 34,
+                    'order' => ['method' => 'getBaseDiscountRefunded', 'amount' => 17],
+                    'creditmemo' => ['method' => 'getBaseDiscountAmount', 'amount' => 17]
+                ],
+                'setBaseTotalInvoicedCost' => [
+                    'result' => 7,
+                    'order' => ['method' => 'getBaseTotalInvoicedCost', 'amount' => 18],
+                    'creditmemo' => ['method' => 'getBaseCost', 'amount' => 11]
+                ],
+            ]],
+        ];
+    }
+
+    private function setBaseAmounts($amounts)
+    {
+        foreach ($amounts as $amountName => $summands) {
+            $this->orderMock->expects($this->once())
+                ->method($amountName)
+                ->with($summands['result']);
+            $this->orderMock->expects($this->once())
+                ->method($summands['order']['method'])
+                ->willReturn($summands['order']['amount']);
+            $this->creditmemoMock->expects($this->any())
+                ->method($summands['creditmemo']['method'])
+                ->willReturn($summands['creditmemo']['amount']);
+        }
+    }
+
+    private function registerItems()
+    {
+        $item1 = $this->getCreditmemoItemMock();
+        $item1->expects($this->once())->method('isDeleted')->willReturn(true);
+        $item1->expects($this->never())->method('setCreditMemo');
+
+        $item2 = $this->getCreditmemoItemMock();
+        $item2->expects($this->at(0))->method('isDeleted')->willReturn(false);
+        $item2->expects($this->once())->method('setCreditMemo')->with($this->creditmemoMock);
+        $item2->expects($this->once())->method('getQty')->willReturn(0);
+        $item2->expects($this->at(3))->method('isDeleted')->with(true);
+        $item2->expects($this->never())->method('register');
+
+        $item3 = $this->getCreditmemoItemMock();
+        $item3->expects($this->once())->method('isDeleted')->willReturn(false);
+        $item3->expects($this->once())->method('setCreditMemo')->with($this->creditmemoMock);
+        $item3->expects($this->once())->method('getQty')->willReturn(1);
+        $item3->expects($this->once())->method('register');
+
+        $this->creditmemoMock->expects($this->any())
+            ->method('getItems')
+            ->willReturn([$item1, $item2, $item3]);
+    }
+
+    private function getCreditmemoItemMock()
+    {
+        return $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoItemInterface::class)
+            ->disableOriginalConstructor()
+            ->setMethods(['isDeleted', 'setCreditMemo', 'getQty', 'register'])
+            ->getMockForAbstractClass();
+    }
+}
diff --git a/app/code/Magento/Sales/Test/Unit/Model/Order/PaymentAdapterTest.php b/app/code/Magento/Sales/Test/Unit/Model/Order/PaymentAdapterTest.php
index 2da2f4bba3f1a..8d4daec7bf8d5 100644
--- a/app/code/Magento/Sales/Test/Unit/Model/Order/PaymentAdapterTest.php
+++ b/app/code/Magento/Sales/Test/Unit/Model/Order/PaymentAdapterTest.php
@@ -16,10 +16,20 @@ class PaymentAdapterTest extends \PHPUnit_Framework_TestCase
     private $subject;
 
     /**
-     * @var \Magento\Sales\Model\Order|\PHPUnit_Framework_MockObject_MockObject
+     * @var \Magento\Sales\Api\Data\OrderInterface|\PHPUnit_Framework_MockObject_MockObject
      */
     private $orderMock;
 
+    /**
+     * @var \Magento\Sales\Api\Data\CreditmemoInterface|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $creditmemoMock;
+
+    /**
+     * @var \Magento\Sales\Model\Order\Creditmemo\RefundOperation|\PHPUnit_Framework_MockObject_MockObject
+     */
+    private $refundOperationMock;
+
     /**
      * @var \Magento\Sales\Api\Data\InvoiceInterface|\PHPUnit_Framework_MockObject_MockObject
      */
@@ -36,6 +46,14 @@ protected function setUp()
             ->disableOriginalConstructor()
             ->getMockForAbstractClass();
 
+        $this->creditmemoMock = $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoInterface::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+
+        $this->refundOperationMock = $this->getMockBuilder(\Magento\Sales\Model\Order\Creditmemo\RefundOperation::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+
         $this->invoiceMock = $this->getMockBuilder(\Magento\Sales\Api\Data\InvoiceInterface::class)
             ->disableOriginalConstructor()
             ->getMockForAbstractClass();
@@ -45,10 +63,24 @@ protected function setUp()
             ->getMock();
 
         $this->subject = new \Magento\Sales\Model\Order\PaymentAdapter(
+            $this->refundOperationMock,
             $this->payOperationMock
         );
     }
 
+    public function testRefund()
+    {
+        $isOnline = true;
+        $this->refundOperationMock->expects($this->once())
+            ->method('execute')
+            ->with($this->creditmemoMock, $this->orderMock, $isOnline)
+            ->willReturn($this->orderMock);
+        $this->assertEquals(
+            $this->orderMock,
+            $this->subject->refund($this->creditmemoMock, $this->orderMock, $isOnline)
+        );
+    }
+
     public function testPay()
     {
         $isOnline = true;
diff --git a/app/code/Magento/Sales/Test/Unit/Model/Service/CreditmemoServiceTest.php b/app/code/Magento/Sales/Test/Unit/Model/Service/CreditmemoServiceTest.php
index daf71daf4a569..73aa1a34c29b0 100644
--- a/app/code/Magento/Sales/Test/Unit/Model/Service/CreditmemoServiceTest.php
+++ b/app/code/Magento/Sales/Test/Unit/Model/Service/CreditmemoServiceTest.php
@@ -5,15 +5,11 @@
  */
 namespace Magento\Sales\Test\Unit\Model\Service;
 
-use Magento\Framework\Pricing\PriceCurrencyInterface;
-use Magento\Framework\TestFramework\Unit\Helper\ObjectManager as ObjectManagerHelper;
-use Magento\Sales\Api\Data\CreditmemoInterface;
 use Magento\Sales\Model\Order;
-use Magento\Sales\Model\Order\Creditmemo;
-use Magento\Sales\Model\Order\Creditmemo\Item;
 
 /**
  * Class CreditmemoServiceTest
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  */
 class CreditmemoServiceTest extends \PHPUnit_Framework_TestCase
 {
@@ -43,7 +39,7 @@ class CreditmemoServiceTest extends \PHPUnit_Framework_TestCase
     protected $creditmemoNotifierMock;
 
     /**
-     * @var PriceCurrencyInterface|\PHPUnit_Framework_MockObject_MockObject
+     * @var \Magento\Framework\Pricing\PriceCurrencyInterface|\PHPUnit_Framework_MockObject_MockObject
      */
     private $priceCurrencyMock;
 
@@ -52,13 +48,16 @@ class CreditmemoServiceTest extends \PHPUnit_Framework_TestCase
      */
     protected $creditmemoService;
 
+    /**
+     * @var \Magento\Framework\TestFramework\Unit\Helper\ObjectManager
+     */
+    private $objectManagerHelper;
+
     /**
      * SetUp
      */
     protected function setUp()
     {
-        $objectManager = new ObjectManagerHelper($this);
-
         $this->creditmemoRepositoryMock = $this->getMockForAbstractClass(
             \Magento\Sales\Api\CreditmemoRepositoryInterface::class,
             ['get'],
@@ -92,9 +91,11 @@ protected function setUp()
             '',
             false
         );
-        $this->priceCurrencyMock = $this->getMockBuilder(PriceCurrencyInterface::class)->getMockForAbstractClass();
+        $this->priceCurrencyMock = $this->getMockBuilder(\Magento\Framework\Pricing\PriceCurrencyInterface::class)
+            ->getMockForAbstractClass();
+        $this->objectManagerHelper = new \Magento\Framework\TestFramework\Unit\Helper\ObjectManager($this);
 
-        $this->creditmemoService = $objectManager->getObject(
+        $this->creditmemoService = $this->objectManagerHelper->getObject(
             \Magento\Sales\Model\Service\CreditmemoService::class,
             [
                 'creditmemoRepository' => $this->creditmemoRepositoryMock,
@@ -198,21 +199,71 @@ public function testNotify()
 
     public function testRefund()
     {
-        $creditMemoMock = $this->getMockBuilder(Creditmemo::class)
-            ->setMethods(['getId', 'getOrder', 'getBaseGrandTotal', 'getAllItems', 'setDoTransaction'])
+        $creditMemoMock = $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoInterface::class)
+            ->setMethods(['getId', 'getOrder', 'getInvoice'])
             ->disableOriginalConstructor()
-            ->getMock();
+            ->getMockForAbstractClass();
         $creditMemoMock->expects($this->once())->method('getId')->willReturn(null);
         $orderMock = $this->getMockBuilder(Order::class)->disableOriginalConstructor()->getMock();
+
         $creditMemoMock->expects($this->atLeastOnce())->method('getOrder')->willReturn($orderMock);
-        $itemMock = $this->getMockBuilder(
-            Item::class
-        )->disableOriginalConstructor()->getMock();
-        $creditMemoMock->expects($this->once())->method('getAllItems')->willReturn([$itemMock]);
-        $itemMock->expects($this->once()) -> method('setCreditMemo')->with($creditMemoMock);
-        $itemMock->expects($this->once()) -> method('getQty')->willReturn(1);
-        $itemMock->expects($this->once()) -> method('register');
-        $creditMemoMock->expects($this->once())->method('setDoTransaction')->with(false);
+        $orderMock->expects($this->once())->method('getBaseTotalRefunded')->willReturn(0);
+        $orderMock->expects($this->once())->method('getBaseTotalPaid')->willReturn(10);
+        $creditMemoMock->expects($this->once())->method('getBaseGrandTotal')->willReturn(10);
+
+        $this->priceCurrencyMock->expects($this->any())
+            ->method('round')
+            ->willReturnArgument(0);
+
+        // Set payment adapter dependency
+        $paymentAdapterMock = $this->getMockBuilder(\Magento\Sales\Model\Order\PaymentAdapterInterface::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+        $this->objectManagerHelper->setBackwardCompatibleProperty(
+            $this->creditmemoService,
+            'paymentAdapter',
+            $paymentAdapterMock
+        );
+
+        // Set resource dependency
+        $resourceMock = $this->getMockBuilder(\Magento\Framework\App\ResourceConnection::class)
+            ->disableOriginalConstructor()
+            ->getMock();
+        $this->objectManagerHelper->setBackwardCompatibleProperty(
+            $this->creditmemoService,
+            'resource',
+            $resourceMock
+        );
+
+        // Set order repository dependency
+        $orderRepositoryMock = $this->getMockBuilder(\Magento\Sales\Api\OrderRepositoryInterface::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+        $this->objectManagerHelper->setBackwardCompatibleProperty(
+            $this->creditmemoService,
+            'orderRepository',
+            $orderRepositoryMock
+        );
+
+        $adapterMock = $this->getMockBuilder(\Magento\Framework\DB\Adapter\AdapterInterface::class)
+            ->disableOriginalConstructor()
+            ->getMockForAbstractClass();
+        $resourceMock->expects($this->once())->method('getConnection')->with('sales')->willReturn($adapterMock);
+        $adapterMock->expects($this->once())->method('beginTransaction');
+        $paymentAdapterMock->expects($this->once())
+            ->method('refund')
+            ->with($creditMemoMock, $orderMock, false)
+            ->willReturn($orderMock);
+        $orderRepositoryMock->expects($this->once())
+            ->method('save')
+            ->with($orderMock);
+        $creditMemoMock->expects($this->once())
+            ->method('getInvoice')
+            ->willReturn(null);
+        $adapterMock->expects($this->once())->method('commit');
+        $this->creditmemoRepositoryMock->expects($this->once())
+            ->method('save');
+
         $this->assertSame($creditMemoMock, $this->creditmemoService->refund($creditMemoMock, true));
     }
 
@@ -225,8 +276,8 @@ public function testRefundExpectsMoneyAvailableToReturn()
         $baseGrandTotal = 10;
         $baseTotalRefunded = 9;
         $baseTotalPaid = 10;
-        $creditMemoMock = $this->getMockBuilder(CreditmemoInterface::class)
-            ->setMethods(['getId', 'getOrder', 'getBaseGrandTotal', 'formatBasePrice'])
+        $creditMemoMock = $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoInterface::class)
+            ->setMethods(['getId', 'getOrder', 'formatBasePrice'])
             ->getMockForAbstractClass();
         $creditMemoMock->expects($this->once())->method('getId')->willReturn(null);
         $orderMock = $this->getMockBuilder(Order::class)->disableOriginalConstructor()->getMock();
@@ -254,7 +305,7 @@ public function testRefundExpectsMoneyAvailableToReturn()
      */
     public function testRefundDoNotExpectsId()
     {
-        $creditMemoMock = $this->getMockBuilder(CreditmemoInterface::class)
+        $creditMemoMock = $this->getMockBuilder(\Magento\Sales\Api\Data\CreditmemoInterface::class)
             ->setMethods(['getId'])
             ->getMockForAbstractClass();
         $creditMemoMock->expects($this->once())->method('getId')->willReturn(444);
diff --git a/app/code/Magento/Sales/etc/di.xml b/app/code/Magento/Sales/etc/di.xml
index bd5fcf871d11b..383650c8688fc 100644
--- a/app/code/Magento/Sales/etc/di.xml
+++ b/app/code/Magento/Sales/etc/di.xml
@@ -430,7 +430,6 @@
         <arguments>
             <argument name="relationProcessors" xsi:type="array">
                 <item name="default" xsi:type="object">Magento\Sales\Model\ResourceModel\Order\Creditmemo\Relation</item>
-                <item name="creditmemo_refund" xsi:type="object">Magento\Sales\Model\ResourceModel\Order\Creditmemo\Relation\Refund</item>
             </argument>
         </arguments>
     </virtualType>