Fix failed static tests

Author: Nazar65

app/code/Magento/Sitemap/Model/Observer.php

@@ -6,7 +6,7 @@
 namespace Magento\Sitemap\Model;
 
 use Magento\Store\Model\App\Emulation;
-use Magento\Framework\App\ObjectManager;
+
 /**
  * Sitemap module observer
  *
@@ -71,32 +71,31 @@ class Observer
     /**
      * @var \Magento\Store\Model\App\Emulation $appEmulation
      */
-    protected $appEmulation;
+    private $appEmulation;
 
     /**
      * Observer constructor.
-     * @param Emulation|null $appEmulation
      * @param \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig
      * @param ResourceModel\Sitemap\CollectionFactory $collectionFactory
      * @param \Magento\Store\Model\StoreManagerInterface $storeManager
      * @param \Magento\Framework\Mail\Template\TransportBuilder $transportBuilder
      * @param \Magento\Framework\Translate\Inline\StateInterface $inlineTranslation
+     * @param Emulation|null $appEmulation
      */
     public function __construct(
-        Emulation $appEmulation = null,
         \Magento\Framework\App\Config\ScopeConfigInterface $scopeConfig,
-        \Magento\Sitemap\Model\ResourceModel\Sitemap\CollectionFactory $collectionFactory,
+        ResourceModel\Sitemap\CollectionFactory $collectionFactory,
         \Magento\Store\Model\StoreManagerInterface $storeManager,
         \Magento\Framework\Mail\Template\TransportBuilder $transportBuilder,
-        \Magento\Framework\Translate\Inline\StateInterface $inlineTranslation
+        \Magento\Framework\Translate\Inline\StateInterface $inlineTranslation,
+        Emulation $appEmulation
     ) {
         $this->_scopeConfig = $scopeConfig;
         $this->_collectionFactory = $collectionFactory;
         $this->_storeManager = $storeManager;
         $this->_transportBuilder = $transportBuilder;
         $this->inlineTranslation = $inlineTranslation;
-        $this->appEmulation = $appEmulation ?: ObjectManager::getInstance()
-            ->get(\Magento\Store\Model\App\Emulation::class);
+        $this->appEmulation = $appEmulation;
     }
 
     /**
@@ -124,10 +123,9 @@ public function scheduledGenerateSitemaps()
         foreach ($collection as $sitemap) {
             /* @var $sitemap \Magento\Sitemap\Model\Sitemap */
             try {
-
                 $this->appEmulation->startEnvironmentEmulation(
                     $sitemap->getStoreId(),
-                    \Magento\Framework\App\Area::AREA_FRONTEND,
+                    'frontend',
                     true
                 );
 
@@ -137,7 +135,6 @@ public function scheduledGenerateSitemaps()
             } finally {
                 $this->appEmulation->stopEnvironmentEmulation();
             }
-
         }
 
         if ($errors && $this->_scopeConfig->getValue(