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: repository_test.rb
    path of file: ./repos/retest/test/retest
    
    the code of the file until where you have to start completion: require 'test_helper'
require_relative 'repository/multiple_test_files_with_user_input.rb'

module Retest
  class RepositoryTest < MiniTest::Test
    def setup
      @subject = Repository.new
    end

    def test_add_file
      @subject.files = ['c.txt']
      assert_equal ['c.txt'], @subject.files

      
    
    def test_remove_file
      @subject.files = ['c.txt']
      assert_equal ['c.txt'], @subject.files

      @subject.remove('c.txt')

      assert_equal [], @subject.files

      @subject.remove('c.txt')
      assert_equal [], @subject.files

      @subject.remove []
      assert_equal [], @subject.files

      @subject.remove nil
      assert_equal [], @subject.files
    end