class TestFileUsage

bundle_test.services.yml in drupal/core/modules/system/tests/modules/bundle_test/bundle_test.services.yml

drupal/core/modules/system/tests/modules/bundle_test/bundle_test.services.yml

file.usage in drupal/core/modules/system/tests/modules/bundle_test/bundle_test.services.yml

Drupal\bundle_test\TestFileUsage

class TestFileUsage extends FileUsageBase {

  /**
   * Implements Drupal\file\FileUsage\FileUsageInterface::add().
   */
  public function add(File $file, $module, $type, $id, $count = 1) {
  }

  /**
   * Implements Drupal\file\FileUsage\FileUsageInterface::delete().
   */
  public function delete(File $file, $module, $type = NULL, $id = NULL, $count = 1) {
  }

  /**
   * Implements Drupal\file\FileUsage\FileUsageInterface::listUsage().
   */
  public function listUsage(File $file) {
  }

}