Testing a facebook canvas app on rails (using Koala) with cucumber

How can I fake the current_user method to stop my cucumber tests failing?

Something like a Given /^I am logged in$/ step.

class ApplicationController < ActionController::Base
  protect_from_forgery

  helper_method :current_user

  def facebook_cookies
    @facebook_cookies ||= Koala::Facebook::OAuth.new.get_user_info_from_cookie(cookies)
  end

  def current_user
    @graph = Koala::Facebook::GraphAPI.new(facebook_cookies['access_token'])
    @current_user = User.find_by_fbid(开发者_如何转开发@graph.get_object("me")["id"]) || User.create(:fbid => @graph.get_object("me")["id"]) 
  end

end

I'm not familiar with Koala, but these are some ideas I've successfully used with other auth frameworks.

1. Define current_user to behave differently in test mode. It's a little ugly.

   class ApplicationController < ActionController::Base
     ...
     def current_user
       if Rails.env == 'test'
         User.create! :username => 'Tester'
       else
         # do normal stuff
       end
     end
     ..
   end
   

2. Create a step that logs in a user for you, and just use it at the beginning of each scenario

   Given /^I am logged in$/ do
     passwd = 'realgoodpassword'
     user = User.create! :username => 'Tester', :password => passwd
     visit login_path
     fill_in 'Username', :with => user.username
     fill_in 'Password', :with => passwd
     click_button 'Sign in'
   end
   

This assumes you are using Capybara to power Cucumber. Webrat might look different; take a look in features/step_definitions/web_steps.rb to get some ideas.