text: from unittest.mock import MagicMock
  
  from wemake_python_styleguide import constants
  from wemake_python_styleguide.visitors.base import BaseFilenameVisitor
  
  
  class _TestingFilenameVisitor(BaseFilenameVisitor):
      def visit_filename(self):
          """Overridden to satisfy abstract base class."""
  
  
  def test_base_filename_run_do_not_call_visit(default_options):
      """Ensures that `run()` does not call `visit()` method for stdin."""
      instance = _TestingFilenameVisitor(
          default_options,
          filename=constants.STDIN,
      )
      instance.visit_filename = MagicMock()
      instance.run()
  
      instance.visit_filename.assert_not_called()
  