diff -u b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/FilePathTest.php b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/FilePathTest.php
--- b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/FilePathTest.php
+++ b/core/modules/migrate_drupal_ui/tests/src/Functional/d7/FilePathTest.php
@@ -7,9 +7,7 @@
 use Drupal\Tests\migrate_drupal_ui\Functional\MigrateUpgradeTestBase;
 
 /**
- * Tests Drupal 7 file migrations from the Migrate UI.
- *
- * Files are created in the test site temp directory.
+ * Tests the Drupal 7 public and private file migrations.
  *
  * @group migrate_drupal_ui
  */
@@ -33,25 +31,11 @@
   protected $fs;
 
   /**
-   * The path to the source private files.
-   *
-   * @var string
-   */
-  protected $private;
-
-  /**
-   * The path to the source public files.
-   *
-   * @var string
-   */
-  protected $public;
-
-  /**
-   * The path to the source temporary files.
+   * The file path variables in the source database.
    *
-   * @var string
+   * @var string[]
    */
-  protected $temporary;
+  protected $basePath = [];
 
   /**
    * The file path variables in the source database.
@@ -71,13 +55,6 @@
   ];
 
   /**
-   * The entity storage for node.
-   *
-   * @var \Drupal\Core\Entity\EntityStorageInterface
-   */
-  protected $nodeStorage;
-
-  /**
    * {@inheritdoc}
    */
   protected function setUp(): void {
@@ -111,9 +88,9 @@
     $this->variable['public'] = $file_public_path;
     $this->variable['temporary'] = $file_temporary_path;
 
-    $this->private = $private;
-    $this->public = $public;
-    $this->temporary = $temporary;
+    $this->basePath['private'] = $private;
+    $this->basePath['public'] = $public;
+    $this->basePath['temporary'] = $temporary;
 
     // Create the source files.
     $this->makeFiles();
@@ -148,8 +125,7 @@
     if (count($drivers) !== 1) {
       $edit['driver'] = $driver;
     }
-    // Set the public and private base paths to be submitted on the Credential
-    // Form.
+    // Set the public and private base paths for the Credential Form.
     $edit['source_private_file_path'] = $this->fs->realpath($this->getSourcePath('private'));
     $edit['source_base_path'] = $this->fs->realpath($this->getSourcePath('public'));
     $edits = $this->translatePostValues($edit);
@@ -169,6 +145,7 @@
     ]);
     $store->set('migrations', $migration_array);
 
+    // Perform the migrations.
     $this->drupalPostForm(NULL, [], 'Perform upgrade');
     $this->resetAll();
     $this->assertFileMigrations();
@@ -219,24 +196,25 @@
 
   /**
    * Creates files for the test.
+   *
+   * The source files are written to a subdirectory of the temporary files
+   * directory of the test sites. The subdirectory path always ends with the
+   * path to the relevant scheme as set in the source variable table.
    */
   protected function makeFiles() {
     // Get file information from the source database.
     $files = $this->getManagedFiles();
     foreach ($files as $file) {
       $scheme = preg_replace('/:.*/', '', $file['uri']);
-      // The source files are written to a subdirectory of the temporary files
-      // directory of the test sites. The subdirectory path always ends with
-      // the path to the relevant scheme as set in the source variable table.
-      $base_path = $this->getSourcePath($scheme);
+
       $path = isset($this->variable[$scheme]) ? $this->variable[$scheme] : '';
-      $base_path = $base_path . '/' . $path;
+      $base_path = $this->getSourcePath($scheme) . '/' . $path;
       $filepath = $base_path . '/' . $file['filename'];
+      // Create the file.
       $source_file = @fopen($filepath, 'w');
       if (!$source_file) {
         // If fopen didn't work, make sure there's a writable directory in
         // place.
-        /** @var \Drupal\Core\File\FileSystem $this ->fs */
         $this->fs = \Drupal::service('file_system');
         $dir = $this->fs->dirname($filepath);
         if (!$this->fs->prepareDirectory($dir, FileSystemInterface:: CREATE_DIRECTORY | FileSystemInterface::MODIFY_PERMISSIONS)) {
@@ -254,31 +232,18 @@
 
   /**
    * Gets the source base path for the Credential form.
+   *
+   * @param string $scheme
+   *   The file scheme.
    */
   public function getSourcePath($scheme) {
-    switch ($scheme) {
-      case 'private':
-        $sub_path = $this->private;
-        break;
-
-      case 'public':
-        $sub_path = $this->public;
-        break;
-
-      case 'temporary':
-        $sub_path = $this->temporary;
-        break;
-
-      default:
-        $sub_path = '';
-        break;
-    }
+    $base_path = isset($this->basePath[$scheme]) ? $this->basePath[$scheme] : '';
     // Puts the source files in the site temp directory.
-    return $this->tempFilesDirectory . '/' . $sub_path;
+    return $this->tempFilesDirectory . '/' . $base_path;
   }
 
   /**
-   * Gets the file data from the source database.
+   * Gets the file data.
    *
    * @return string[][]
    *   Data from the source file_managed table.