如何对在循环中采用标准输入的方法进行单元测试？

Question

我在class QuestionList中有如下方法

def ask_all
    @questions.each do |question|
        question.ask
        @player.add_answer(gets.chomp)
    end
end

这些问题有整数答案，并且答案对于这个测试不必是正确的 - 只需要接收一个整数并将其添加到列表@player.answers 中，使用class Player 中的以下方法

def add_answer(answer)
    @answers << answer
end

当对方法进行单元测试时，如何模拟用户对QuestionList.ask_all 的gets.chomp 的输入：

class QuestionListTest < Test::Unit::TestCase

    def setup
        ...
    end

    def test_ask_all
        #unit test for 'QuestionList.ask_all' here
    end

end

Answer 1

1。将ask_all 修改为与输入无关：

def ask_all
    @questions.each do |question|
        question.ask
        @player.add_answer(question.retrieve_answer)
    end
end

2。修改Question类，使其拥有retrieve_answer方法：

class Question
  def ask
    # even better, delegate this to some other class
    #  to make it possible to work with console,
    #  batches, whatever depending on settings
    print "Enter an answer >"
  end
  def retrieve_answer
    # for now it’s enough
    gets.chomp
  end
end

3。模拟Question 类以非交互方式“提问”：

class QuestionListTest < Test::Unit::TestCase

    def setup
      Question.define_method :ask do
        print "I am mock for prompting ... "
      end
      Question.define_method :retrieve_answer do
        # be aware of wrong input as well!
        [*(1..10), 'wrong input', ''].sample.tap do |answer|
          puts "mocked answer is #{answer}." 
        end
      end
    end

    def test_ask_all
      expect(ask_all).to match_array(...)
    end
end