You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: authentication_generator.rb
    path of file: ./repos/authentication-zero/lib/generators/authentication
    
    the code of the file until where you have to start completion: require "rails/generator
    
  def create_test_files
    directory "test_unit/controllers/#{format}", "test/controllers"
    directory "test_unit/mailers/", "test/mailers"
    directory "test_unit/system", "test/system" unless options.api?
    template  "test_unit/test_helper.rb", "test/test_helper.rb", force: true
    template  "test_unit/application_system_test_case.rb", "test/application_system_test_case.rb", force: true unless options.api?
  end