Relationship validations

再繼續之前，我們要先增加一些 Relationship model 的驗證機制。

下面的 test 和應用程式碼非常直觀。就像之前產生的 user fixture（Section 6.2.5），relationship fixture 也違反了遷移的唯一約束性。這個問題的解決方法也和之前一樣，刪除自動產生的 fixture。

Listing 12.4: 測試 Relationship model 的驗證機制

test/models/relationship_test.rb

require 'test_helper'

class RelationshipTest < ActiveSupport::TestCase

  def setup
    @relationship = Relationship.new(follower_id: 1, followed_id: 2)
  end

  test "should be valid" do
    assert @relationship.valid?
  end

  test "should require a follower_id" do
    @relationship.follower_id = nil
    assert_not @relationship.valid?
  end

  test "should require a followed_id" do
    @relationship.followed_id = nil
    assert_not @relationship.valid?
  end
end

Listing 12.5: 增加 Relationship model 驗證機制

app/models/relationship.rb

class Relationship < ActiveRecord::Base
  belongs_to :follower, class_name: "User"
  belongs_to :followed, class_name: "User"
  validates :follower_id, presence: true
  validates :followed_id, presence: true
end

Listing 12.6: 移除 relationship fixture 內容

test/fixtures/relationships.yml

# empty

現在執行測試應該會通過：

Listing 12.7: Green

$ bundle exec rake test