RSpec has_many 通过#<ActiveRecord::Associations::CollectionProxy>

Question

我有一个这样的关系模型：

class Physician < ApplicationRecord
  has_many :appointments
  has_many :patients, through: :appointments
end

class Appointment < ApplicationRecord
  belongs_to :physician
  belongs_to :patient
end

class Patient < ApplicationRecord
  has_many :appointments
  has_many :physicians, through: :appointments
end

我需要创建一个有很多患者的医师，对吗？ 等等我的测试：

let!(:physician) { create(:physician) }
let!(:patients) { create_list(:patients, 2) }

我这样做了：

before { physician.patients << patients }

我想用这个测试生成的json

expect(physician.as_json).to eq({
  "id" => physician.id,
  "name" => physician.name,
  "patients" => physician.patients
})

我期待它会通过，但因为这个#<ActiveRecord::Associations::CollectionProxy>而失败了

我使用 binding.pry 进行了检查：

physician.patients == patients 结果是true

您介意帮助我吗，我是不是遗漏了什么？

Answer 1

要将医生和患者联系起来，只需将密钥传递给create_list：

let!(:patients) { create_list(:patients, 2, physician: physician ) }

或者您可以将其声明为：

let(:physician) { create(:physician, patients: build_list(patients: 2)) }

但是正如@TomLord 所提到的，测试本身仍然被破坏。您需要测试生成的散列 - 因为包含关联会导致它被转换为序列化散列：

{
  "id" => 1,
  "name" => "Dr Suess",
  "patients" => [
     {
        "id" => 1,
        "name" => "The Cat in The Hat"
     },
     {
        "id" => 2,
        "name" => "The Grinch"
     },
  ]
}

使用eq 测试准确的输出并不是最优的，因为对序列化的每次更改都会破坏测试。相反，您可以使用 include matcher 指定必须存在的内容：

describe '#as_json' do
   let!(:physician) { create(:physician) }
   let!(:patients) { create_list(:patients, 2) }
   subject(:serialized) { physician.as_json } 

   it { should include({
        "id" => physician.id,
        "name" => physician.name
   }) }
   it "includes the patients" do
      expect(serialized["patients"].length).to eq patients.length
      expect(serialized["patients"]).to include patients.first.as_json
      expect(serialized["patients"]).to include patients.last.as_json
   end
end

除非您已覆盖 as_json 方法，否则此规范应该会失败，因为您需要明确包含与 physician.as_json(include: :patients) 的关联。