Rspec：如何检查是否调用了另一个类的方法

RSpec：如何检查是否调用了另一个类的方法？

ruby
# app/models/order.rb
class Order
  def initialize(payment_processor)
    @payment_processor = payment_processor
  end
  def process_payment(amount)
    @payment_processor.process(amount)
  end
end
# app/models/payment_processor.rb
class PaymentProcessor
  def process(amount)
    # 这里是支付处理的逻辑
  end
end

ruby
# spec/models/order_spec.rb
require 'rails_helper'
RSpec.describe Order do
  describe '#process_payment' do
    it 'calls the process method on PaymentProcessor' do
      payment_processor = instance_double('PaymentProcessor', process: true)
      order = Order.new(payment_processor)
      
      expect(payment_processor).to receive(:process).with(100)
      order.process_payment(100)
    end
  end
end

shell
bundle exec rspec