使用RSpec和FactoryGirl测试关联验证

Question

我正在尝试为验证方法编写RSpec测试。记录更新，保存或创建时会触发此方法。以下是我迄今为止：

product.rb（模型）

class Product < ActiveRecord::Base 

validate :single_product 

    # Detects if a product has more than one SKU when attempting to set the single product field as true 
    # The sku association needs to map an attribute block in order to count the number of records successfully 
    # The standard self.skus.count is performed using the record ID, which none of the SKUs currently have 
    # 
    # @return [boolean] 
    def single_product 
    if self.single && self.skus.map { |s| s.active }.count > 1 
     errors.add(:single, " product cannot be set if the product has more than one SKU.") 
     return false 
    end 
    end 
end 

products.rb（FactoryGirl测试数据）

FactoryGirl.define do 
    factory :product do 
     sequence(:name) { |n| "#{Faker::Lorem.word}#{Faker::Lorem.characters(8)}#{n}" } 
     meta_description { Faker::Lorem.characters(10) } 
     short_description { Faker::Lorem.characters(15) } 
     description { Faker::Lorem.characters(20) } 
     sku { Faker::Lorem.characters(5) } 
     sequence(:part_number) { |n| "GA#{n}" } 
     featured false 
     active false 
     sequence(:weighting) { |n| n } 
     single false 

     association :category 

     factory :product_skus do 
      after(:build) do |product, evaluator| 
       build_list(:sku, 3, product: product) 
      end 
     end 
    end 
end 

product_spec.rb（单位测试）

require 'spec_helper' 

describe Product do 
    describe "Setting a product as a single product" do 
     let!(:product) { build(:product_skus, single: true) } 

     context "when the product has more than one SKU" do 

      it "should raise an error" do 
       expect(product).to have(1).errors_on(:single) 
      end 
     end 
    end 
end 

从singe_product方法中可以看出，当单个属性设置为true并且产品具有多个关联的SKU时，我试图在单个属性上触发错误。但是，在运行测试时，产品没有关联的SKU，因此上述单元测试失败。

如何在FactoryGirl中创建一个记录并生成相关的SKU（可以计算在内）（例如：product.skus.count）并进行验证？

Answer 1

你可以写这就像

it 'should raise an error' do 
    product = build(:product_skus, single: true) 

    expect(product).not_to be_valid 
    end