ruby-on-rails-3之参数数量错误(0 代表 1)(ArgumentError)

我正在使用 devise作为身份验证系统并创建了一个场景。

Scenario: Home page have a login page 
    When I go to the home page 
    And user is not logged in 
    Then I should see "Sign In" 

用于步骤定义

When /^user is not logged in$/ do 
  signed_in? == false 
end 

我还在 cucumber 世界中添加了设计助手。

World(Devise::Controllers::Helpers) 

cucumber 产生了这个错误:

And user is not logged in           # features/step_definitions/web_steps.rb:260 
      wrong number of arguments (0 for 1) (ArgumentError) 
      ./features/step_definitions/web_steps.rb:261:in `/^user is not logged in$/' 
      features/manage_home_page.feature:13:in `And user is not logged in' 

为什么会产生它以及如何修复它？

更新
signed_in?的定义方法是

  # Return true if the given scope is signed in session. If no scope given, return 
  # true if any scope is signed in. Does not run authentication hooks. 
  def signed_in?(scope=nil) 
    [ scope || Devise.mappings.keys ].flatten.any? do |scope|  
      warden.authenticate?(:scope => scope) 
    end 
  end 

它在设计中定义，我通过编写此代码将帮助程序添加到 cucumber World(Devise::Controllers::Helpers)进入 cucumber 的paths.rb文件。

请您参考如下方法:

试试这个

When /^user is not logged in$/ do 
  user_signed_in?.should be_false 
end 

更新
我认为你需要做这样的事情

When /^user is not logged in$/ do |user|  
  #check here user not logged in 
end 

或者
您可以尝试将您的功能修改为

Scenario: Home page has a login page 
  Given I am on the home page 
  And I am not logged in 
  Then I should see "Sign In" 

然后在步骤中

Given /^user is not logged in$/ do 
  visit('users/sign_out')  # this will ensure that the user is not logged in 
end