This is a helpful RSpec pattern I've been playing with lately with great success

rspec_attributes.rb

let(:vehicle)             { FactoryGirl.create(:vehicle, vehicle_attributes) }
let(:vehicle_attributes)  { {} }

describe "#to_s"
  subject { vehicle.to_s }
  let(:vehicle_attributes) { {name: "Carzilla"} }
  it { should == "Carzilla" }
end