diff --git a/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php b/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php
index 224c907..8cf45a1 100644
--- a/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php
+++ b/core/lib/Drupal/Component/Discovery/YamlDirectoryDiscovery.php
@@ -125,15 +125,12 @@ protected function getIdentifier($file, array $data) {
    */
   protected function findFiles() {
     $file_list = [];
-    $pattern = '/\.yml$/i';
-
     foreach ($this->directories as $provider => $directories) {
       $directories = (array) $directories;
       foreach ($directories as $directory) {
         if (is_dir($directory)) {
-          $files = new RegexDirectoryIterator($directory, $pattern);
           /** @var \SplFileInfo $fileInfo */
-          foreach ($files as $fileInfo) {
+          foreach ($this->getDirectoryIterator($directory) as $fileInfo) {
             $file_list[$fileInfo->getPathname()] = $provider;
           }
         }
@@ -142,4 +139,22 @@ protected function findFiles() {
     return $file_list;
   }
 
+  /**
+   * Gets an iterator to loop over the files in the provided directory.
+   *
+   * This method is exists so that it is easy to replace this functionality in
+   * a class that extends this one. For example, it could be used to make the
+   * scan recursive.
+   *
+   * @param $directory
+   *   The directory to scan.
+   *
+   * @return \Traversable
+   *   An \Traversable object or array where the values are \SplFileInfo
+   *   objects.
+   */
+  protected function getDirectoryIterator($directory) {
+    return new RegexDirectoryIterator($directory, '/\.yml$/i');
+  }
+
 }