rspec中的while循环答案

【问题标题】：While loops in rspecrspec中的while循环
【发布时间】：2016-02-22 07:54:10
【问题描述】：

我试图了解在 rspec 中测试 while 循环的最佳方法是什么。

我允许用户输入他/她想玩的游戏类型。

def get_action
    gets.strip.downcase
end

def type_of_game
    puts "Enter the type of game you would like to play (human v. human, computer v. computer, or human v. computer):"
    gametype = get_action
    until (gametype == "human v. human" || gametype == "computer v. computer" || gametype == "human v. computer")
        puts "Please enter a valid game"
        gametype = get_action
    end
    return gametype
end

目前我在 rspec 中有这个，但它会导致无限循环

require "minitest/spec"  
require "minitest/autorun"


describe Game do 
   before :each do
    @game = Game.new    
   end


   it "should prompt to user to enter their gametype again if not human v. human, computer v. computer, or human v. compouter" do
      def @game.get_action; "human v. machine" end
      expect(@game.type_of_game).to eql("Please enter a valid game")
   end

感谢您的帮助

【问题讨论】：

标签： ruby rspec

【解决方案1】：

我将重写它如下，因为它允许我们存根loop 并屈服（从而避免您遇到的无限循环问题）。这种方法的一个警告是，您将收到游戏类型“人与机器”，因为它在一次迭代后产生。

类

class Game
  def get_action
    gets.strip.downcase
  end

  def type_of_game
    puts 'Enter the type of game you would like to play (human v. human, computer v. computer, or human v. computer):'
    gametype = get_action
    loop do
      break if gametype == 'human v. human' || gametype == 'computer v. computer' || gametype == 'human v. computer'
      puts 'Please enter a valid game'
      gametype = get_action
    end

    gametype
  end
end

Rspec (3.3.0)

require_relative 'path/to/game'

describe Game do
  subject { Game.new }

  it 'prompts the user to enter their gametype again if it is incorrect' do
    allow(subject).to receive(:gets).and_return('human v. machine')
    allow(subject).to receive(:loop).and_yield

    expect { subject.type_of_game }
      .to output(/Please enter a valid game/)
      .to_stdout
  end

  it 'does not prompt the user to enter their gametype if it is correct' do
    allow(subject).to receive(:gets).and_return('human v. human')

    expect { subject.type_of_game }
      .to_not output(/Please enter a valid game/)
      .to_stdout
  end

  it 'returns the specified gametype if valid' do
    allow(subject).to receive(:gets).and_return('human v. human')

    expect(subject.type_of_game).to eq('human v. human')
  end
end

我使用正则表达式匹配器 (//) 的原因是因为stdout 还包括 输入您想玩的游戏类型（人类与人类、计算机与计算机或人类 v .computer)：我们不关心。

【讨论】：

【解决方案2】：

发生的情况是您的方法get_action 已被存根以不断返回无效响应。（干得好！）

所以你的type_of_game 方法会反复调用get_action，一遍又一遍。

您要测试的是您的type_of_game 方法是否正确地向用户发送了一条消息。

要在 rspec (3.0) 中执行此操作，您可以像这样使用 output 匹配器：

expect { @game.type_of_game }.to output("Please enter a valid game").to_stdout

如果您不使用 rspec 3.0 Testing STDOUT output in Rspec，请查看此 SO 答案

【讨论】：