Add unit test coverage for this changes.

Author: ktpl-prakash

app/code/Magento/Integration/Model/CustomerTokenService.php

@@ -66,15 +66,15 @@ class CustomerTokenService implements \Magento\Integration\Api\CustomerTokenServ
     public function __construct(
         TokenModelFactory $tokenModelFactory,
         AccountManagementInterface $accountManagement,
-        TokenCollectionFactory $tokenModelCollectionFactory,      
+        TokenCollectionFactory $tokenModelCollectionFactory,
         CredentialsValidator $validatorHelper,
         ManagerInterface $eventManager
     ) {
         $this->tokenModelFactory = $tokenModelFactory;
         $this->accountManagement = $accountManagement;
         $this->tokenModelCollectionFactory = $tokenModelCollectionFactory;
-        $this->eventManager = $eventManager;
         $this->validatorHelper = $validatorHelper;
+        $this->eventManager = $eventManager;
     }
 
     /**

app/code/Magento/Integration/Test/Unit/Model/CustomerTokenServiceTest.php

@@ -32,6 +32,9 @@ class CustomerTokenServiceTest extends \PHPUnit\Framework\TestCase
     /** @var \Magento\Integration\Model\Oauth\Token|\PHPUnit_Framework_MockObject_MockObject */
     private $_tokenMock;
 
+    /** @var \Magento\Framework\Event\ManagerInterface|\PHPUnit_Framework_MockObject_MockObject */
+    protected $manager;
+
     protected function setUp()
     {
         $this->_tokenFactoryMock = $this->getMockBuilder(\Magento\Integration\Model\Oauth\TokenFactory::class)
@@ -67,11 +70,14 @@ protected function setUp()
             \Magento\Integration\Model\CredentialsValidator::class
         )->disableOriginalConstructor()->getMock();
 
+        $this->manager = $this->createMock(\Magento\Framework\Event\ManagerInterface::class);
+        
         $this->_tokenService = new \Magento\Integration\Model\CustomerTokenService(
             $this->_tokenFactoryMock,
             $this->_accountManagementMock,
             $this->_tokenModelCollectionFactoryMock,
-            $this->validatorHelperMock
+            $this->validatorHelperMock,
+            $this->manager
         );
     }