MC-33165: Cannot change customer group

Author: tsviklinskyi

app/code/Magento/Sales/Test/Unit/Model/AdminOrder/CreateTest.php

@@ -30,13 +30,14 @@
 use Magento\Sales\Model\Order\Item as OrderItem;
 use Magento\Sales\Model\ResourceModel\Order\Item\Collection as ItemCollection;
 use Magento\Store\Api\Data\StoreInterface;
-use PHPUnit_Framework_MockObject_MockObject as MockObject;
+use PHPUnit\Framework\TestCase;
+use PHPUnit\Framework\MockObject\MockObject;
 
 /**
  * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
  * @SuppressWarnings(PHPMD.TooManyFields)
  */
-class CreateTest extends \PHPUnit\Framework\TestCase
+class CreateTest extends TestCase
 {
     const CUSTOMER_ID = 1;
 
@@ -46,12 +47,12 @@ class CreateTest extends \PHPUnit\Framework\TestCase
     private $adminOrderCreate;
 
     /**
-     * @var CartRepositoryInterface|\PHPUnit_Framework_MockObject_MockObject
+     * @var CartRepositoryInterface|MockObject
      */
     private $quoteRepository;
 
     /**
-     * @var QuoteFactory|\PHPUnit_Framework_MockObject_MockObject
+     * @var QuoteFactory|MockObject
      */
     private $quoteFactory;
 
@@ -111,7 +112,7 @@ protected function setUp()
             ->setMethods(['getForCustomer'])
             ->getMockForAbstractClass();
 
-        $this->sessionQuote = $this->getMockBuilder(\Magento\Backend\Model\Session\Quote::class)
+        $this->sessionQuote = $this->getMockBuilder(SessionQuote::class)
             ->disableOriginalConstructor()
             ->setMethods(
                 [