ACP2E-3493: fix static and unit test errors, small refactoring

Author: alzota

app/code/Magento/Persistent/Model/CleanExpiredPersistentQuotes.php

@@ -61,7 +61,7 @@ public function execute(int $websiteId): void
     private function processStoreQuotes(StoreInterface $store): void
     {
         $batchSize = 500;
-        $lastProcessedId = 0;
+        $lastProcessedId = $count = 0;
 
         while (true) {
             $quotesToProcess = $this->expiredPersistentQuotesCollection
@@ -72,6 +72,7 @@ private function processStoreQuotes(StoreInterface $store): void
             }
 
             foreach ($quotesToProcess as $quote) {
+                $count++;
                 try {
                     $this->quoteRepository->delete($quote);
                     $lastProcessedId = (int)$quote->getId();
@@ -82,12 +83,14 @@ private function processStoreQuotes(StoreInterface $store): void
                         (string)$e
                     ));
                 }
+                if ($count % $batchSize === 0) {
+                   $this->snapshot->clear($quote);
+                }
                 $quote->clearInstance();
                 unset($quote);
             }
 
             $quotesToProcess->clear();
-            $this->snapshot->clear();
             unset($quotesToProcess);
         }
     }

app/code/Magento/Persistent/Test/Unit/Model/CleanExpiredPersistentQuotesTest.php

@@ -16,11 +16,15 @@
 use Magento\Store\Model\StoreManagerInterface;
 use Magento\Quote\Model\ResourceModel\Quote\Collection;
 use PHPUnit\Framework\MockObject\Exception;
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Psr\Log\LoggerInterface;
 use Magento\Store\Api\Data\StoreInterface;
 use Magento\Store\Model\Website;
 
+/**
+ * @SuppressWarnings(PHPMD.CouplingBetweenObjects)
+ */
 class CleanExpiredPersistentQuotesTest extends TestCase
 {
     /**
@@ -38,6 +42,11 @@ class CleanExpiredPersistentQuotesTest extends TestCase
      */
     private QuoteRepository $quoteRepositoryMock;
 
+    /**
+     * @var MockObject|Snapshot
+     */
+    private MockObject|Snapshot $snapshotMock;
+
     /**
      * @var LoggerInterface
      */