Question

我有点困惑：

class SessionsController < ApplicationController
    def new
        @user = User.new
    end
end

我原以为所有以下三个期望都会过去：

require 'spec_helper'

describe SessionsController do
    describe '#new' do
        let(:user) { FactoryGirl.build(:user, name: nil, email: nil, password: nil, password_confirmation: nil)}
        before { get :new }

        it { expect(assigns(:user)).to eq user }

        it { expect(assigns(:user)).to eq User.new }

        it "should assign stubbed user" do
            assigns(:user).should eq user
        end
    end
end

然而我明白了： FFF

故障：

  1) SessionsController#new should eq #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>
     Failure/Error: it { expect(assigns(:user)).to eq user }

       expected: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>
            got: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>

       (compared using ==)

       Diff:
     # ./spec/controllers/sessions_controller_spec.rb:8:in `block (3 levels) in <top (required)>'

  2) SessionsController#new should eq #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>
     Failure/Error: it { expect(assigns(:user)).to eq User.new }

       expected: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>
            got: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>

       (compared using ==)

       Diff:
     # ./spec/controllers/sessions_controller_spec.rb:10:in `block (3 levels) in <top (required)>'

  3) SessionsController#new should assign stubbed user
     Failure/Error: assigns(:user).should eq user

       expected: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>
            got: #<User id: nil, name: nil, email: nil, created_at: nil, updated_at: nil, password_digest: nil>

       (compared using ==)

       Diff:
     # ./spec/controllers/sessions_controller_spec.rb:13:in `block (3 levels) in <top (required)>'

我的意思是什么？ Diff部分甚至是空的。如果我使用be匹配器，我会理解，但我正在使用eq，那么发生了什么？

Answer 1

在ActiveRecord中，如果两个模型对象具有相同的类和相同的非零主键值，则认为它们是相等的。

因此，如果两个相同的对象具有零id个值，则它们不相等。

请参阅https://github.com/rails/rails/blob/master/activerecord/lib/active_record/core.rb#L290

这可能看起来很奇怪，但如果您认为那两个对象（如果它们曾经保存过）将由数据库分配两个不同的id值，那么这是有意义的。因此，在分配ActiveRecord模型对象的id之前，无法将其与另一个进行有意义的比较。

Answer 2

尝试使用eq方法比较user.attributes，它应该通过。

rspec的eq方法实际测试的是什么？

2 个答案: