MAGETWO-91701: Newsletter subscription is not correctly updated when …

…user is registered on 2 stores

- Adding additional checking for guest customers

dev/tests/integration/testsuite/Magento/Newsletter/Model/Plugin/PluginTest.php

@@ -63,14 +63,14 @@ public function testCustomerCreated()
             ->setFirstname('Firstname')
             ->setLastname('Lastname')
             ->setEmail('[email protected]');
-        $createdCustomer = $this->customerRepository->save(
+        $this->customerRepository->save(
             $customerDataObject,
             $this->accountManagement->getPasswordHash('password')
         );
 
         $subscriber->loadByEmail('[email protected]');
         $this->assertTrue($subscriber->isSubscribed());
-        $this->assertEquals((int)$createdCustomer->getId(), (int)$subscriber->getCustomerId());
+        $this->assertEquals(0, (int)$subscriber->getCustomerId());
     }
 
     /**

dev/tests/integration/testsuite/Magento/Newsletter/Model/ResourceModel/SubscriberTest.php

@@ -40,15 +40,13 @@ public function testLoadByCustomerDataWithCustomerId()
      * @magentoDataFixture Magento/Newsletter/_files/subscribers.php
      * @magentoDataFixture Magento/Customer/_files/two_customers.php
      */
-    public function testLoadByCustomerDataWithoutCustomerId()
+    public function testTryLoadByCustomerDataWithoutCustomerId()
     {
         /** @var \Magento\Customer\Api\CustomerRepositoryInterface $customerRepository */
         $customerRepository = Bootstrap::getObjectManager()
             ->create(\Magento\Customer\Api\CustomerRepositoryInterface::class);
         $customerData = $customerRepository->getById(2);
         $result = $this->_resourceModel->loadByCustomerData($customerData);
-
-        $this->assertEquals(0, $result['customer_id']);
-        $this->assertEquals('[email protected]', $result['subscriber_email']);
+        $this->assertEmpty($result);
     }
 }