RSpec snippets. More info at http://karolgalanciak.com/blog/2014/03/03/test-driven-rails-part-2/

articles_controller_spec.rb

describe ArticlesController do

  describe "inactive article" do

    let(:article) { double(:article, active?: false, id: 1) }

    before(:each) do
      allow(Article).to receive(:find) { article }
    end

    describe "user is logged in" do

      context "user is an admin" do

        let(:user) { double(:user, admin?: true) }

        it "renders article" do
          allow(controller).to receive(:current_user).and_return(admin)
          get :show, id: article.id
          expect(response).to render_template :show
        end
      end

      context "user is not an admin" do

        let(:user) { double(User, admin?: false) }

        it "redirects to articles path" do
          allow(controller).to receive(:current_user).and_return(user)
          get :show, id: article.id
          expect(response).to redirect_to articles_path
        end
      end

      context "user is not logged in" do

        before(:each) do
          allow(controller).to receive(:current_user).and_return(nil)
        end

        it "redirects to articles path" do
          get :show, id: article.id
          expect(flash[:error]).not_to be nil
          expect(response).to redirect_to root_path
        end
      end
    end
  end
end

capybara_spec.rb

feature "User Registration" do

  context "when visiting new user path" do

    background do
      visit new_user_path
    end

    context "registering with valid data" do

      given(:email) { "[email protected]" }

      background do
        fill_form_with_valid_data(email: email)
      end

      scenario "new user is created" do
        expect do
          register
        end.to change(User, :count).by(1)
      end

      context "notifications" do

        background do
          register
        end

        scenario "confirmation email is sent to the user" do
          expect(all_email_addresses).to include email
        end

        scenario "notification is sent to the admin" do
          expect(all_email_addresses).to include "[email protected]"
        end

        scenario "2 emails are sent" do
          expect(all_emails.count).to eq 2
        end

      end

    end

  end

end

def fill_form_with_valid_data(args={})
  email = args.fetch(:email, "[email protected]")
  fill_in "email", with: email
  fill_in "user_password", with: "my-super-secret-password"
  fill_in "user_password_confirmation", with: "my-super-secret-password"
  fill_in "age", with: 22
  select "Poland", from: "country"
  check "policy"
end

def register
  click_button "Register"
end

mailer_macros.rb

module MailerMacros

  def last_email
    ActionMailer::Base.deliveries.last
  end

  def last_email_address
    last_email.to.join
  end

  def reset_email
    ActionMailer::Base.deliveries = []
  end

  def reset_with_delayed_job_deliveries
    ActionMailer::Base.deliveries = []
  end

  def all_emails
    ActionMailer::Base.deliveries
  end

  def all_emails_sent_count
    ActionMailer::Base.deliveries.count
  end

  def all_email_addresses
    all_emails.map(&:to).flatten
  end

end

user_spec.rb

let(:user) { FactoryGirl.create(:inactive_user) }

describe “#activate” do

  it “makes user active” do
    expect(user.activate).to change { user.active }.from(false).to(true)
  end

end