title: Devise Test Helper - sign_in does not work
body: <p>For some reason, I can not get the devise helper method sign_in to work. current_user keeps on being null. Any idea what the problem could be?</p>
  
  <p>Test:</p>
  
  <pre><code>  before :each do
      @user = FactoryGirl.create :user
      sign_in @user
    end
  
    describe "GET index" do
      it "assigns all subscribers as @subscribers" do
        subscriber = @user.subscribers.create! valid_attributes
        get :index
        assigns(:subscribers).should eq([subscriber])
      end
    end
  </code></pre>
  
  <p>Implementation:</p>
  
  <pre><code>  def index
      @subscribers = current_user.subscribers.all    &lt;------- ERROR
  
      respond_to do |format|
        format.html # index.html.erb
        format.json { render json: @subscribers }
      end
    end
  
  Error:
   NoMethodError:
         undefined method `subscribers' for nil:NilClass
  </code></pre>
  
  <p>Any help is appreciated. Thanks!</p>