application_controller_spec.rb

require 'spec_helper'

describe ApplicationController do

  describe "#require_login" do
    context "when the user is logged in" do
      it "does nothing" do
      end
    end
    context "when the user is not logged in" do
      before do
        controller.stub(:logged_in?).and_return(false)
      end

      it "redirect to the login path" do
        controller.should_receive(:redirect_to).with(login_path)
        controller.send(:require_login)
      end
    end
  end
end

articles_controller_spec.rb

require 'spec_helper'
require 'ostruct'

describe ArticlesController do

  describe '#index' do
    it "assigns articles" do
      # Article.stub(:all).and_return([ :article1, :article2 ])
      # Article.should_receive(:all).

      get :index

      expect(assigns(:articles)).to_not be_nil
      # expect(assigns(:articles)).to eq([ :article1, :article2 ])
    end
  end

  context "when the user logged in" do

    before do
      controller.stub(:require_login).and_return(true)
    end

    describe "#create" do

      context "when the article params are valid" do
        it "creates the article" do
          post :create, article: { title: "title", body: "body" }

          # asserts
          expect(response).to redirect_to(article_path(Article.last))

        end

        it "redirects to the show page for the article"
      end

      context "when the article params are invalid" do
        it "renders new" do
          fake_article = stub('Fake Article',valid?: false)
          Article.stub(:create).and_return(fake_article)

          post :create

          expect(response).to render_template(:new)
        end
      end



      context "when the article does exist"
      context "when the article is not valid"
    end
  end

  context "when the user is not logged in" do

  end


end