the-power-of-let.rb

describe Wombat do
  let(:active_user) do
    user = User.new
    user.tap(&:make_active)
  end

  context "with an active user" do
    it "is a cuddly creator" do
      expect(Wombat.new(active_user)).to be_cuddly
    end
  end
  
  context "with an active overriden user" do
    let(:active_user) do
      # we do something here to override the global active user
      # and since it isn't 'fetched' until you call upon it
      # this one will be used instead of the one in the outer
      # block.
    end
    
    it "is a cuddly creator" do
      # until active_user is hit in the next line it is not created
      expect(Wombat.new(active_user)).to be_cuddly
    end
  end
end