test approach

using_rspec_stuff.rb

context 'order' do
  let :first_payment do
    Payment.create
  end

  let :last_payment do
    Payment.create
  end

  let :payments do
    [first_payment, last_payment]
  end

  before do
    payments
  end

  it "should be ordered by payment id" do
    expect(Payment.all).to eq payments
  end
end

without_rspec_stuff.rb

it 'returns the payments ordered by the id' do
  first_payment, last_payment = Payment.create, Payment.create

  expect(Payment.all).to eq [first_payment, last_payment]
end