Rails/RSpec - writing tests for original helper me

Question

I'm on the chapter 5 exercises for Michael Hartl's Rails Tutorial and am trying to wrap my head around how Rails/Rspec is testing a helper method full_title in app/helpers/application_helper.rb. All of my tests are in spec/requests/static_pages_spec.rb and within them, I'm calling full_title to cut down on code bloat.

So, in order to test the original full_title I create a test in spec/helpers/application_helpers_spec.rb and include it via spec/support/utilities.rb. The code is passing, but I want to understand the process (order to operations) to what is going on. Thank you.

Can I think of it like this?

1. Rspec begins to run static_pages_spec.rb (including utilities.rb)
2. Rspec sees the full_title method in static_pages_spec.rb
3. Rspec begins to run application_helper_spec.rb
4. Rspec sees describe "full_title" do in application_helper_spec.rb
5. Rspec looks up original full_title method and finishes test for application_helper_spec.rb
6. Rspec finishes tests in static_pages_spec.rb, iterating through above process whenfull_title` is called.

static_pages_spec.rb

require 'spec_helper'

describe "Static pages" do

  subject { page }

  shared_examples_for "all static pages" do
    it { should have_selector('h1',    text: heading) }
    it { should have_selector('title', text: full_title(page_title)) }
  end

  describe "Home page" do
    before { visit root_path }
    let(:heading)    { 'Sample App' }
    let(:page_title) { '' }

    it_should_behave_like "all static pages"
    it { should_not have_selector 'title', text: '| Home' }
  end

  describe "Help page" do
    before { visit help_path }
    let(:heading) { 'Help' }
    let(:page_title) { 'Help' }

    it_should_behave_like "all static pages"
  end

  describe "About page" do
    before { visit about_path }
    let(:heading) { 'About' }
    let(:page_title) { 'About Us' }

    it_should_behave_like "all static pages"
  end

  describe "Contact page" do
    before { visit contact_path }
    let(:heading) { 'Contact' }
    let(:page_title) { 'Contact' }

    it_should_behave_like "all static pages"   
  end

  it "should have the right links on the layout" do
    visit root_path
    click_link "About"
    page.should have_selector 'title', text: full_title('About Us')
    click_link "Help"
    page.should have_selector 'title', text: full_title('Help')
    click_link "Contact"
    page.should have_selector 'title', text: full_title('Contact')
    click_link "Home"
    page.should have_selector 'title', text: full_title('')
    click_link "Sign up now!"
    page.should have_selector 'title', text: full_title('Sign up')
    click_link "sample app"
    page.should_not have_selector 'title', text: full_title('| Home')
  end
end

application_helper_spec.rb

require 'spec_helper'

describe ApplicationHelper do

  describe "full_title" do
    it "should include the page title" do
      full_title("foo").should =~ /foo/
    end

    it "should include the base title" do
      full_title("foo").should =~ /^Ruby on Rails Tutorial Sample App/
    end

    it "should not include a bar for the home page" do
      full_title("").should_not =~ /\|/
    end
  end
end

application_helper.rb

module ApplicationHelper

    #Returns the full title on a per-page basis.
    def full_title(page_title)
        base_title = "Ruby on Rails Tutorial Sample App"
        if page_title.empty?
            base_title
        else
            "#{base_title} | #{page_title}"
        end
    end
end

Answer 1

Think about it this way:

The 'full_title' called in static_pages_spec.rb (including utilities.rb) is running the 'full_title' method described in application_helper.rb.

The application_helper_spec.rb is validating the string/value (page_title) passed through full_title. If I'm not mistaken, it does this each time the full_title method is called in your tests.