redirect_to :action => :index in Rspec

I tried to google for the exact solution for my problem but didn't found any appropriate result, so I'm asking for the solution here.

Here is the important information
Ruby Version : ruby 2.2.4p230 (2015-12-16 revision 53155) [x86_64-darwin15]
Rails Version : Rails 4.2.0
Rspec Version : 3.5.4

I've a controller which has an action called clearCart which basically functions to clearing the cart session

Here is my action

def clearCart
  session[:cart] = nil
  redirect_to :action => :index
end

The main aim for the above action is to test redirect_to :action => :index.

Routes for the same action (if needed)

get 'cart/clear' => 'cart#clearCart'

Here is the Rspec test to test the same action

describe "GET #clearCart" do
  it "should clear cart" do
    get :clearCart
    subject { get :clearCart }
    subject.should redirect_to :action => :index
    # expect(response).to redirect_to(:index)
    # response.should redirect_to :index
    # before { post :clearCart }
    # render 'index'
    # specify { response.should redirect_to('frontend/cart/index') }
  end
end

(comments are the possible way which I tried to execute the test)

Here is my index action (if needed)

def index
  render 'frontend/cart/index' ,layout: false
end

I usually refer RELISH for guidance.

Thanks in advance for help.