hogehgoe

hoge_spec.rb

RSpec.configure do |config|
  config.mock_with :rspec
end

class PriceCalc
  def initialize(order)
    @order = order
  end

  def price_with_tax
    @order.total_price * 1.08
  end
end

describe 'Hoge' do
  let(:order_mock) { double('order') }
  before do
    allow(order_mock).to receive(:total_price) { 1000 }
    expect(order_mock).to receive(:total_price).once
  end

  subject { PriceCalc.new(order_mock).price_with_tax }
  it { is_expected.to eq 1080 }
end