Issue #3150661 by cburschka: FileFieldRSSContentTest uses XPath incorrectly

(cherry picked from commit 6b769d1e)

core/modules/file/tests/src/Functional/FileFieldRSSContentTest.php

@@ -63,14 +63,13 @@ public function testFileFieldRSSContent() {
 
     // Check that the RSS enclosure appears in the RSS feed.
     $this->drupalGet('rss.xml');
-    $uploaded_filename = str_replace('public://', '', $node_file->getFileUri());
     $selector = sprintf(
-      'enclosure[@url="%s"][@length="%s"][@type="%s"]',
-      file_create_url("public://$uploaded_filename", ['absolute' => TRUE]),
+      '//enclosure[@url="%s" and @length="%s" and @type="%s"]',
+      file_create_url($node_file->getFileUri()),
       $node_file->getSize(),
       $node_file->getMimeType()
     );
-    $this->assertNotNull($this->getSession()->getDriver()->find('xpath', $selector), 'File field RSS enclosure is displayed when viewing the RSS feed.');
+    $this->assertNotEmpty($this->getSession()->getDriver()->find($selector), 'File field RSS enclosure is displayed when viewing the RSS feed.');
   }
 
 }