ruby-on-rails - rails rspec 在测试时访问其他表

Question

我是 Rails 的新手，发现自己在理解数据库表之间的关系时遇到了一些问题(我猜？)。

我的问题如下:

我有一个 Users 表，其中包含有关用户的信息，包括他们的电子邮件地址和另一个包含“游戏”的表，我想管理那些玩过的玩家。当玩家想要提交他们的游戏时，他们必须通过他们的电子邮件地址指定参与游戏的用户。我想验证这些玩家是否真的存在。

我的游戏模型:

class Game < ActiveRecord::Base
  attr_accessible :caster1, :caster2, :faction1, :faction2, :player1, :player2, :points, :won

  before_save { |game| player1 = player1.downcase }
  before_save { |game| player2 = player2.downcase }

  validate :existence_of_both_players

  ...
  (some more validations)
  ...

  private
    def existence_of_both_players
        User.exists?(:email => :player1.downcase) && User.exists?(:email => :player2.downcase)
    end
end

我的测试用例如下:

require 'spec_helper'

describe Game do

  before do
    @game = Game.new( player1:  "foobar@example.com",
                      faction1: "Some faction",
                      caster1:  "Some caster",
                      player2:  "bazbaz@example.com",
                      faction2: "Some other faction",
                      caster2:  "Some other caster",
                      points:   35,
                      won:      true)
  end

  ...
  (some other specs)
  ...

  describe "saving a game" do
    let(:player1) { User.create(name:                   "Example1", 
                                email:                  "example1@foo.bar",
                                password:               "foobar",
                                password_confirmation:  "foobar") }
    let(:player2) { User.create(name:                   "Example2", 
                                email:                  "example2@foo.bar",
                                password:               "foobar",
                                password_confirmation:  "foobar") }

    describe "with invalid players" do

      describe "when both players do not exist" do
        before { @game.player1 = @game.player2 = "some_wrong_user@example.com" }
        it { should_not be_valid }
      end

      describe "when player1 does not exist" do
        before { @game.player2 = player2 }
        it { should_not be_valid }
      end

      describe "when player2 does not exist" do
        before { @game.player1 = player1 }
        it { should_not be_valid }
      end
    end

    describe "with valid players" do
      before do 
        @game.player1 = player1
        @game.player2 = player2
      end

      it { should be_valid }
    end
  end
end

(抱歉代码太多，我只是觉得它会有所帮助)。

我的测试失败了，我很确定原因很明显，遗憾的是对我来说不是。

Failures:

  1) Game saving a game with invalid players when both players do not exist 
     Failure/Error: it { should_not be_valid }
       expected valid? to return false, got true
     # ./spec/models/game_spec.rb:108:in `block (5 levels) in <top (required)>'
...

我真的想不通，为什么这行不通。我阅读了 Rails 书籍并观看了几个截屏视频，但没有一个能正确解释我的问题。

由于这是我在 stackoverflow 上的第一篇文章，如果这篇文章过于冗长，请告诉我。提前致谢。

Answer 1

自定义验证器方法应该调用 errors.add 来发出错误信号。所以在你的情况下是这样的:

    def existence_of_both_players
      player_one_exists = User.find_by_email :player1.downcase
      player_two_exists = User.find_by_email :player2.downcase
      unless player_one_exists and player_two_exists
          errors.add :game, "both players need to exist"
      end
    end

阅读更多关于 ActiveRecord Validations and Callbacks 的指南.