黄瓜;硒的webdriver - 如何使用谷歌浏览器作为测试的浏览器，而不是Firefox的

有关我的Rails应用程序3.1黄瓜情况下，我用了@javascript标记，因此硒被激活。
我收到以下错误：

For a Cucumber scenario on my Rails 3.1 app, I used the @javascript tag, so Selenium is activated. I get the following error:

Could not find Firefox binary (os=macosx). Make sure Firefox is installed or set the path manually with Selenium::WebDriver::Firefox::Binary.path= (Selenium::WebDriver::Error::WebDriverError)

如果可能的话，我想使用谷歌浏览器浏览器 - 火狐没有（我还没有安装）。这可能吗？可以做些什么？

If possible, I'd like to use Google Chrome as the browser - not Firefox (which I haven't installed). Is this possible? What could be done?

其实，不应该黄瓜/硒检测浏览器并使用它吗？

In fact, shouldn't Cucumber/Selenium detect a browser and use it?

==== ====编辑

====EDIT====

后加入

Capybara.register_driver :selenium do |app|
  Capybara::Selenium::Driver.new(app, :browser => :chrome)
end

...到功能/支持/ env.rb，
现在我得到这个错误：

...to features/support/env.rb, I now get this error:

Unable to find the chromedriver executable. Please download the server from http://code.google.com/p/chromium/downloads/list and place it somewhere on your PATH. More info at http://code.google.com/p/selenium/wiki/ChromeDriver. (Selenium::WebDriver::Error::WebDriverError)
  ./features/step_definitions/web_steps.rb:45:in `/^(?:|I )am on (.+)$/'
  features/update_memories.feature:11:in `Given I am on the home page'

我从here,我尝试了把chromedriver可执行文件在/ usr / bin中，但我仍然得到上述错误。

I've downloaded from here, and I've tried putting the chromedriver executable in /usr/bin, but I still get the above error.

====编辑2 ====

====EDIT 2====

往前一步并运行后命令搭配chmod + X的/ usr /斌/ chromedriver，如下的建议，我现在正在运行后，黄瓜得到一个新的错误：

After going one step further and running "sudo chmod +x /usr/bin/chromedriver" as suggested below, I now get a new error after running cucumber:

@javascript
  Scenario: navigate to memory update page from home page              # features/update_memories.feature:11
    Given I am on the home page                                        # features/step_definitions/web_steps.rb:44
      unable to connect to chromedriver http://127.0.0.1:57870 (Selenium::WebDriver::Error::WebDriverError)
      ./features/step_definitions/web_steps.rb:45:in `/^(?:|I )am on (.+)$/'
      features/update_memories.feature:12:in `Given I am on the home page'
    When I activate the edit memory switch for the memory "I played"   # features/step_definitions/memories/memory_steps.rb:5
    Then I should be on the edit memory page for the memory "I played" # features/step_definitions/web_steps.rb:187
      PGError: server closed the connection unexpectedly
        This probably means the server terminated abnormally
        before or while processing the request.
      : ROLLBACK (ActiveRecord::StatementInvalid)

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