黄瓜-RackTest无法进行Selenium和WebKit都成功进行的测试

Question

I am using Cucumber with Capybara to build my testing framework for a site. I have found a way using hooks to switch between the Capybara driver in Cucumber. I want to be able just to use RackTest when I am not testing for JavaScript because I was lead to believe RackTest is faster since it doesn't render the page. Right now I have create 3 identical test that jump to Google and check that the title says Google. Each test uses a different driver. The Selenium and WebKit test work fine but the RackTest fails on the " I should see the title "Google" " test. I have attached a copy of my feature and steps and testing gems to this post.

Feature:

Feature: Rack Test
  In order to run test faster
  As a tester
  I want to use Rack Test to preform all non-javascript related test

  Scenario: Visit a page and check title
    When  I go to "http://www.google.com"
    Then  I should see the title "Google"

  @firefox
  Scenario: Visit a page and check title in Firefox
    When  I go to "http://www.google.com"
    Then  I should see the title "Google"

  @webkit
  Scenario: Visit a page and check title in WebKit
    When  I go to "http://www.google.com"
    Then  I should see the title "Google"

Steps:

When /^I go to "(http:\/\/[^"]*)"$/ do |url|
  visit url
end


Then /^I should see the title "([^"]*)"$/ do |title_cont|
  page.should have_selector "title", text: title_cont
end

Hooks:

Before('@firefox') do
  Capybara.current_driver = :selenium
end

Before('@webkit') do
  Capybara.current_driver = :webkit
end

After('@firefox, @webkit') do
  Capybara.use_default_driver
end

Gemfile:

group :test do
  gem 'capybara'
  gem 'capybara-webkit'
  gem 'cucumber'
  gem 'cucumber-rails'
  gem 'database_cleaner'
  gem 'factory_girl_rails'
  gem "rack-test", require: "rack/test"
  gem 'rspec'
  gem 'selenium-webdriver'
end

Answer 1

That's because rack-test can only test Rack applications (eg your Ruby On Rails website). It's not browser-based solution, while both Selenium and WebKit are. That's why rack-test can't access external websites (Google in your case).