diff -u b/core/tests/Drupal/KernelTests/Core/File/UnmanagedCopyTest.php b/core/tests/Drupal/KernelTests/Core/File/UnmanagedCopyTest.php
--- b/core/tests/Drupal/KernelTests/Core/File/UnmanagedCopyTest.php
+++ b/core/tests/Drupal/KernelTests/Core/File/UnmanagedCopyTest.php
@@ -86,9 +86,9 @@
     $this->assertFilePermissions($new_filepath, Settings::get('file_chmod_file', FileSystem::CHMOD_FILE));
 
     // Copy the file into a subdirectory that does not exist.
-    $new_filepath = file_unmanaged_copy($uri, drupal_dirname($uri) . '/sub/' . drupal_basename($uri), FILE_EXISTS_ERROR);
+    $new_filepath = file_unmanaged_copy($uri, \Drupal::service('file_system')->dirname($uri) . '/sub/' . \Drupal::service('file_system')->basename($uri), FILE_EXISTS_ERROR);
     $this->assertTrue($new_filepath, 'Copying into same directory works.');
-    $this->assertNotEqual($new_filepath, $uri, 'Copied file has a new name.');
+    self::assertNotEquals($new_filepath, $uri, 'Copied file has a new name.');
     $this->assertTrue(file_exists($uri), 'Original file exists after copying onto itself.');
     $this->assertTrue(file_exists($new_filepath), 'Copied file exists after copying onto itself.');
     $this->assertFilePermissions($new_filepath, Settings::get('file_chmod_file', FileSystem::CHMOD_FILE));
diff -u b/core/tests/Drupal/KernelTests/Core/File/UnmanagedMoveTest.php b/core/tests/Drupal/KernelTests/Core/File/UnmanagedMoveTest.php
--- b/core/tests/Drupal/KernelTests/Core/File/UnmanagedMoveTest.php
+++ b/core/tests/Drupal/KernelTests/Core/File/UnmanagedMoveTest.php
@@ -40,9 +40,9 @@
 
     // Moving the file into a subdirectory that does not exist.
     $desired_filepath = 'public://sub/' . $this->randomMachineName();
-    $newest_filepath= file_unmanaged_move($newer_filepath, $desired_filepath, FILE_EXISTS_ERROR);
+    $newest_filepath = file_unmanaged_move($newer_filepath, $desired_filepath, FILE_EXISTS_ERROR);
     $this->assertTrue($newest_filepath, 'Move was successful.');
-    $this->assertEqual($newest_filepath, $desired_filepath, 'Returned expected filepath.');
+    self::assertEquals($newest_filepath, $desired_filepath, 'Returned expected filepath.');
     $this->assertTrue(file_exists($newest_filepath), 'File exists at the new location.');
     $this->assertFalse(file_exists($newer_filepath), 'No file remains at the old location.');
     $this->assertFilePermissions($newest_filepath, Settings::get('file_chmod_file', FileSystem::CHMOD_FILE));