Ruby on rails 如何测试自定义验证器？

我有以下验证器：

# Source: http://guides.rubyonrails.org/active_record_validations_callbacks.html#custom-validators
# app/validators/email_validator.rb

class EmailValidator < ActiveModel::EachValidator
  def validate_each(object, attribute, value)
    unless value =~ /^([^@\s]+)@((?:[-a-z0-9]+\.)+[a-z]{2,})$/i
      object.errors[attribute] << (options[:message] || "is not formatted properly") 
    end
  end
end

#来源：http://guides.rubyonrails.org/active_record_validations_callbacks.html#custom-验证器
#app/validators/email_validator.rb
类EmailValidatorobject.errors[attribute]这里是我为该文件编写的一个快速规范，它运行良好。我认为存根可能会被清理，但希望这将足以让你开始

require 'spec_helper'

describe 'EmailValidator' do

  before(:each) do
    @validator = EmailValidator.new({:attributes => {}})
    @mock = mock('model')
    @mock.stub('errors').and_return([])
    @mock.errors.stub('[]').and_return({})
    @mock.errors[].stub('<<')
  end

  it 'should validate valid address' do
    @mock.should_not_receive('errors')    
    @validator.validate_each(@mock, 'email', 'test@test.com')
  end

  it 'should validate invalid address' do
    @mock.errors[].should_receive('<<')
    @validator.validate_each(@mock, 'email', 'notvalid')
  end  
end

require'spec\u helper'
请描述“EmailValidator”的用途
在…之前做
@validator=EmailValidator.new（{:attributes=>{}）
@mock=mock（'模型'）
@mock.stub（'errors'）。和_返回（[]）
@mock.errors.stub（'[]'）和_return（{}）
@mock.errors[]存根（“我不太喜欢另一种方法，因为它将测试与实现联系得太近了。而且，这也很难遵循。这是我最终使用的方法。请记住，这是对我的验证器实际操作的过度简化…只是想更简单地演示一下。肯定有优化拟作出的修订

class OmniauthValidator < ActiveModel::Validator
  def validate(record)
    if !record.omniauth_provider.nil? && !%w(facebook github).include?(record.omniauth_provider)
      record.errors[:omniauth_provider] << 'Invalid omniauth provider'
    end
  end
end

基本上，我的方法是创建一个伪对象“validable”，这样我们就可以实际测试它的结果，而不是对实现的每个部分都有期望。再举一个例子，扩展一个对象，而不是在规范中创建新类。BitcoinAddressValidator是一个自定义的验证器

require 'rails_helper'

module BitcoinAddressTest
  def self.extended(parent)
    class << parent
      include ActiveModel::Validations
      attr_accessor :address
      validates :address, bitcoin_address: true
    end
  end
end

describe BitcoinAddressValidator do
  subject(:model) { Object.new.extend(BitcoinAddressTest) }

  it 'has invalid bitcoin address' do
    model.address = 'invalid-bitcoin-address'
    expect(model.valid?).to be_falsey
    expect(model.errors[:address].size).to eq(1)
  end

  # ...
end

require'rails\u helper'
模块位寻址测试
def自我扩展（父级）
类使用Neals伟大的示例作为基础，我提出了以下内容（对于Rails和RSpec3）

我建议为测试目的创建一个匿名类，例如：

require 'spec_helper'
require 'active_model'
require 'email_validator'

RSpec.describe EmailValidator do
  subject do
    Class.new do
      include ActiveModel::Validations    
      attr_accessor :email
      validates :email, email: true
    end.new
  end

  describe 'empty email addresses' do
    ['', nil].each do |email_address|
      describe "when email address is #{email_address}" do
        it "does not add an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).not_to include 'is not a valid email address'
        end
      end
    end
  end

  describe 'invalid email addresses' do
    ['nope', '@', 'foo@bar.com.', '.', ' '].each do |email_address|
      describe "when email address is #{email_address}" do

        it "adds an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).to include 'is not a valid email address'
        end
      end
    end
  end

  describe 'valid email addresses' do
    ['foo@bar.com', 'foo@bar.bar.co'].each do |email_address|
      describe "when email address is #{email_address}" do
        it "does not add an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).not_to include 'is not a valid email address'
        end
      end
    end
  end
end

这将防止硬编码类，如
validable
，它们可以在多个规范中引用，由于不相关的验证之间的交互而导致意外和难以调试的行为，您正试图单独测试这些行为。
受@Gazler的答案启发，我提出了以下建议：模拟模型，但是t使用
ActiveModel:：Errors
作为Errors对象。这大大减少了模拟

require 'spec_helper'

RSpec.describe EmailValidator, type: :validator do
  subject { EmailValidator.new(attributes: { any: true }) }

  describe '#validate_each' do
    let(:errors) { ActiveModel::Errors.new(OpenStruct.new) }
    let(:record) {
      instance_double(ActiveModel::Validations, errors: errors)
    }

    context 'valid email' do
      it 'does not increase error count' do
        expect {
          subject.validate_each(record, :email, 'test@example.com')
        }.to_not change(errors, :count)
      end
    end

    context 'invalid email' do
      it 'increases the error count' do
        expect {
          subject.validate_each(record, :email, 'fakeemail')
        }.to change(errors, :count)
      end

      it 'has the correct error message' do
        expect {
          subject.validate_each(record, :email, 'fakeemail')
        }.to change { errors.first }.to [:email, 'is not an email']
      end
    end
  end
end

很好。不知道mock（‘model’）我将尝试了解更多信息。这是旧的RSpec文档，但模拟构造函数保持不变。模型只是模拟的标识符。你也可以用工厂在功能上实现它。我认为工厂太过分了。我们只需要一个空类来包含错误数组。在更新版本的Rails上（我使用的是4.1）您需要为验证器指定一些属性，以避免出现ArgumentError—只要属性不为空，传入什么并不重要，因此类似于
@validator=EmailValidator.new（{:attributes=>{:foo=>:bar}）
会成功的。我喜欢这样做，因为我喜欢通过ActiveModel:：Validations模块测试验证。否则，你会将测试绑定到脆弱的ActiveModel实现上。对于Rails 4.1.6，我得到了“：attributes cannot be blank”在我更改validates_with调用以包含属性名称之前，例如使用OmniauthValidator验证属性：“omniauth_provider”
使用Rails 4.1.7，我能够绕过：属性不能为空
validates:omniauth\u provider出错，omniauth:true
嘿，我希望看到优化！关于验证测试的文档不多。很好，我认为这是一个比公认答案更干净的解决方案。您不需要包括
ActiveModel:：Model
，而且创建一个非ymous类，例如
subject{class.new{include-ActiveModel:：Validations；attr\u访问器：slug；validate:slug，slug:true}.new}
这是2020年的好答案（rspec-rails
4.0
）。
require 'spec_helper'
require 'active_model'
require 'email_validator'

RSpec.describe EmailValidator do
  subject do
    Class.new do
      include ActiveModel::Validations    
      attr_accessor :email
      validates :email, email: true
    end.new
  end

  describe 'empty email addresses' do
    ['', nil].each do |email_address|
      describe "when email address is #{email_address}" do
        it "does not add an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).not_to include 'is not a valid email address'
        end
      end
    end
  end

  describe 'invalid email addresses' do
    ['nope', '@', 'foo@bar.com.', '.', ' '].each do |email_address|
      describe "when email address is #{email_address}" do

        it "adds an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).to include 'is not a valid email address'
        end
      end
    end
  end

  describe 'valid email addresses' do
    ['foo@bar.com', 'foo@bar.bar.co'].each do |email_address|
      describe "when email address is #{email_address}" do
        it "does not add an error" do
          subject.email = email_address
          subject.validate
          expect(subject.errors[:email]).not_to include 'is not a valid email address'
        end
      end
    end
  end
end

require 'spec_helper'

RSpec.describe EmailValidator, type: :validator do
  subject { EmailValidator.new(attributes: { any: true }) }

  describe '#validate_each' do
    let(:errors) { ActiveModel::Errors.new(OpenStruct.new) }
    let(:record) {
      instance_double(ActiveModel::Validations, errors: errors)
    }

    context 'valid email' do
      it 'does not increase error count' do
        expect {
          subject.validate_each(record, :email, 'test@example.com')
        }.to_not change(errors, :count)
      end
    end

    context 'invalid email' do
      it 'increases the error count' do
        expect {
          subject.validate_each(record, :email, 'fakeemail')
        }.to change(errors, :count)
      end

      it 'has the correct error message' do
        expect {
          subject.validate_each(record, :email, 'fakeemail')
        }.to change { errors.first }.to [:email, 'is not an email']
      end
    end
  end
end