testing without accessing db.rb

describe "#bar" do
  let(:foo){FactoryGirl.build_stubbed(:foo)}
  let(:bar_id){double("bar_id")}
  let(:bar){double("bar")}
  subject{foo.bar}
  before do
    foo.stub(:bar_id){bar_id}
    Foo.stub(:find).with(bar_id){bar}
  end

  it{should eq bar}
end