ruby-on-rails – Ruby新手的可变范围问题

require 'spec_helper'

describe PagesController do
  render_views

  pages = ['home','contact','about','help']

  before(:each) do
    @base_title = "Ruby on Rails Tutorial Sample App | "
  end

  pages.each do |page|
    describe "GET '#{page}'" do
      it "should be successful" do
        get "#{page}"
        response.should be_success
      end

      it "should have the right title" do
        get "#{page}"
        response.should have_selector("title",:content => @base_title + page.capitalize)
      end
    end
  end

end

我在上面的例子中感到困惑的是,我可以用这个替换’pages’变量：

@pages = ['home','help']

它仍然有效.这是为什么？ ‘@pages’和’pages’有何不同？

另一个令人困惑的事情是,这两个导致测试失败：

pages = ['home','help']
@base_title = "Ruby on Rails Tutorial Sample App | "

和

before(:each) do
  pages = ['home','help']
  @base_title = "Ruby on Rails Tutorial Sample App | "
end

为什么以上两个例子失败了？为什么代码看起来必须像我在第一个代码片段中发布的那样？我认为这与变量范围有关,但我仍然是Ruby的新手,所以我正在寻找更深入的理解.

FWIW,我是一名经验丰富的C#开发人员,因此获得可比较的Java或C#代码将有助于我理解这个或写得很好的描述.

谢谢你的支持.

编辑：
我将@base_title移到’before’块之外时添加了错误消息.

Failure/Error: response.should have_selector("title",:content => @base_title + page.capitalize)
NoMethodError:
   You have a nil object when you didn't expect it!
   You might have expected an instance of Array.
   The error occurred while evaluating nil.+
 # ./spec/controllers/pages_controller_spec.rb:21:in `block (4 levels) in <top (required)>'