model_spec.rb

  # mock-based (interaction)
  # db independent, but tied to implementation (I can change the AR call without affecting the behavior and this will fail)
  context "data gathering" do
    it "finds all indicators associated with the given sector and includes indicators not associated with any sectors" do
      sector = stub_model(Sector, :id => 6)

      Indicator.should_receive(:where).with("sector_id is null or sector_id = ?", sector.id)

      Indicator.for_sector(sector)
    end
  end


  # traditional (data-based)
  # slower but focused on behavior, doesn't verify the interaction, but also doesn't ties the spec to the AR finder
  context "data gathering" do
    it "finds all indicators associated with the given sector and includes indicators not associated with any sectors" do
      sector = Factory(:sector)
      indicators = Array.new(2) { Factory(:indicator, :sector => sector) }
      indicators << Factory(:indicator)

      2.times { Factory(:indicator, :sector => Factory(:sector)) }

      Indicator.for_sector(sector).should eq(indicators)
    end
  end

  # integrated with model with fine-grained assertions
  context "#for_sector" do
    let(:sector) { Factory(:sector) }
  
    it "finds indicators with no sector" do
      indicator = Factory(:indicator)
      Indicator.for_sector(sector).should == [indicator]
    end
  
    it "finds indicators with the given sector" do
      indicator = Factory(:indicator, :sector => sector)
      Indicator.for_sector(sector).should == [indicator]
    end
  
    it "ignores indicators associated with other sectors" do
      indicator = Factory(:indicator, :sector => Factory(:sector))
      Indicator.for_sector(sector).should == []
    end
  end