MC-33069: Stabilize Unit tests

Author: zakdma

app/code/Magento/ImportExport/Helper/Report.php

@@ -111,11 +111,13 @@ public function getReportAbsolutePath($fileName)
      * Retrieve report file size
      *
      * @param string $filename
-     * @return int|mixed
+     * @return int|null
      */
     public function getReportSize($filename)
     {
-        return $this->varDirectory->stat($this->getFilePath($filename))['size'];
+        $statResult = $this->varDirectory->stat($this->getFilePath($filename));
+
+        return $statResult['size'] ?? null;
     }
 
     /**

app/code/Magento/ImportExport/Test/Unit/Helper/ReportTest.php

@@ -93,7 +93,7 @@ protected function setUp(): void
         $this->varDirectory->expects($this->any())->method('getRelativePath')->willReturn('path');
         $this->varDirectory->expects($this->any())->method('readFile')->willReturn('contents');
         $this->varDirectory->expects($this->any())->method('isFile')->willReturn(true);
-        $this->varDirectory->expects($this->any())->method('stat')->willReturn(100);
+        $this->varDirectory->expects($this->any())->method('stat')->willReturn(false);
         $this->filesystem->expects($this->any())->method('getDirectoryWrite')->willReturn($this->varDirectory);
         $this->objectManagerHelper = new ObjectManagerHelper($this);
         $this->report = $this->objectManagerHelper->getObject(