ruby – initialize’：rack-test需要一个机架应用程序,但没有给

从Selenium切换到PhantomJs / Poltergeist时,我一直收到此错误.
谁知道我做错了什么？如果我将驱动程序切换到selenium,脚本可以正常工作.每当我注释掉default_driver =：selenium并替换为 javascript_driver =：poltergeist时,我会遇到这个错误.

initialize': rack-test requires a rack application,but none was given (ArgumentError)

这都是ruby文件,没有rails.

require 'rubygems'
require 'capybara'
require 'capybara/dsl'
require "open-uri"
# require "date"
# require 'active_support/core_ext/integer/inflections'
require 'capybara/poltergeist'
# require 'selenium-webdriver'
require 'pry'
require 'phantomjs'
# require 'database_cleaner'

Capybara.run_server = false
Capybara.javascript_driver = :poltergeist
# Capybara.default_driver = :selenium
Capybara.app_host = 'https://www.sameplsite.com'


module MyCapybaraTest
  class Test
    include Capybara::DSL

    def login_site
        visit('https://www.sameplsite.com')
        # binding.pry
        click_link('Log in')
        fill_in('email',:with => 'joefrank@sharklasers.com')
        fill_in('password',:with => 'passwordpassword')
        check('checkbox_remember')
        click_button('Log in')
    end

    def click_right_game
        click_link('Create Contest')
        all('.boxed')[1].click
        check('Free practice')
        click_link('Create 1 Head-to-Head')
        save_and_open_page
    end

    def output_game_link
        url = URI.parse(current_url)
        puts url
    end

  end
end


t = MyCapybaraTest::Test.new
t.login_fanduel
t.click_right_game
t.output_game_link