Ruby 初学者：类、实例变量、访问器、rspec答案

【问题标题】：Ruby beginner: class, instance variable, accessor, rspecRuby 初学者：类、实例变量、访问器、rspec
【发布时间】：2016-10-13 08:05:17
【问题描述】：

所以我正在尝试重新创建一款名为 Ciao Ciao 的棋盘游戏。我还没有完成，但我一直被卡住，非常感谢一些帮助。到目前为止，我已经制作了以下 3 个类和 rspec 文件：

播放器类

require_relative 'die'

class Player
attr_reader :name
attr_accessor :token, :position, :point

def initialize(name, token, position, point)
    @name = name
    @token = token
    @position = position
    @point = point
end

def advance
    @position += @number #basically I want the player to advance when he rolls between 1-4 but not sure how to connect it to the Die class here.
end

def lie
    @token -= 1 #here I want the player to lose a token if he rolls between 5-6
    @position == 0 #and have to start again from position 0
end

def score
    @token -= 1
    @position == 0
    @point += 1
end
end

游戏类

require_relative 'player'
require_relative 'die'

class Game
def initialize(title)
    @title = title
    @players = []
end

def join(player)
    @players << player
end

def play
    puts "There are #{@players.size} players in the current round of #{@title}."
    @players.each do |player|
    die = Die.new
    case die.roll
    when 1..4
        puts "#{player.name} just rolled #{die.roll}!"
        player.advance
        puts "#{player.name} advances to #{player.position}!"
    when 5..6
        puts "#{player.name} just rolled #{die.roll}!"
        player.lie
        puts "#{player.name} is down to #{player.token} and starts at #{player.name}!"
    end

    puts "#{player.name} has #{player.point} points and is at #{player.position}. He has #{player.token} token(s) left."

    if player.position >= 10
        player.score
        puts "#{player.name} scores a point for reaching the endzone!"
    end

    if player.token == 0 
        @players.delete(player)
        puts "#{player.name} has been eliminated."
    end
    end
end
end

模具类

class Die
attr_reader :number

def initialize
end

def roll
    @number = rand(1..6)
end
end

rspec 文件

require_relative 'game'

describe Game do
before do
    @game = Game.new("chaochao")

    @initial_token == 4
    @initial_position == 0
    @initial_point == 0
    @player = Player.new("iswg", @initial_token, @initial_position, @initial_point)

    @game.join(@player)
end

it "advances the player if a number between 1 and 4 is rolled" do
    @game.stub(:roll).and_return(3)
    @game.play
    @player.position.should == @initial_position + 3
end

it "makes the player lie if a number between 5 and 6 is rolled" do
    @game.stub(:roll).and_return(5)
    @game.play
    @player.token.should == @initial_token - 1
end
end

我在运行 rspec 文件时不断收到以下错误消息：

失败：

1) 如果掷出 1 到 4 之间的数字，游戏会推进玩家失败/错误：@game.play 无方法错误：未定义的方法-' for nil:NilClass # ./player.rb:19:inlie' # ./game.rb:24:in block in play' # ./game.rb:16:ineach' # ./game.rb:16:in play' # ./game_spec.rb:17:inblock (2 个级别) in '

2) 如果掷出 5 到 6 之间的数字，游戏会使玩家撒谎失败/错误：@game.play 无方法错误：未定义的方法+' for nil:NilClass # ./player.rb:15:inadvance' # ./game.rb:21:in block in play' # ./game.rb:16:ineach' # ./game.rb:16:in play' # ./game_spec.rb:23:inblock (2 个级别) in '

所以错误消息指向 Player 类下的 Advance/lie 方法，但我不知道我做错了什么。也请随时指出其他错误。提前非常感谢。

【问题讨论】：

查看您的示例设置。不是初始化 @initial_token，而是将其与 4 进行比较。无论好坏，当您引用未初始化的实例变量时，它总是返回 nil — 因此，您要求的是 nil，而不是设置实例变量等于某个值并继续前进。

标签： ruby class rspec instance-variables accessor

【解决方案1】：

这不是全部问题，而是一个问题。

你的第一个错误对我来说有点突出。 player.lie 应该只在掷骰为 5 或 6 时被调用，但您将 roll 方法存根以返回 3。或者是吗？

roll 是 Die 类的一个方法，但是您将 @game 存根，它是 Game 类的一个实例。

【讨论】：