rspecでエラーが出ます

Question

rspec specを実行したところ以下のエラーが出ました

Post Validations creates successfully
Failure/Error: expect(post).to be_valid
expected #<Post id: nil, title: "aaaaaaaaaa", content: "aaaaaaaaaaaaaaaaaaaa", category_id: nil, user_id: nil, created_at: nil, updated_at: nil> to be valid, but got errors: Category can't be blank

関係ありそうな箇所を載せます

spec/models/post_spec.rb

context 'Validations' do
    let(:post) { build(:post) }
  
    it 'creates successfully' do 
      expect(post).to be_valid
    end
  
    it 'is not valid without a category' do 
      post.category_id = nil
      expect(post).not_to be_valid
    end
  
    it 'is not valid without a title' do 
      post.title = nil
      expect(post).not_to be_valid
    end
  
    it 'is not valid  without a user_id' do
      post.user_id = nil
      expect(post).not_to be_valid
    end
  
    it 'is not valid  with a title, shorter than 5 characters' do 
      post.title = 'a' * 4
      expect(post).not_to be_valid
    end
  
    it 'is not valid  with a title, longer than 255 characters' do 
      post.title = 'a' * 260
      expect(post).not_to be_valid
    end
  
    it 'is not valid without a content' do 
      post.content = nil
      expect(post).not_to be_valid
    end
  
    it 'is not valid  with a content, shorter than 20 characters' do 
      post.content = 'a' * 10
      expect(post).not_to be_valid
    end
  
    it 'is not valid  with a content, longer than 1000 characters' do 
      post.content = 'a' * 1050
      expect(post).not_to be_valid
    end
  end  

spec/factories/posts.rb

FactoryBot.define do
  factory :post do
    title {'a' * 10}
    content {'a' * 20}
    user
    category
    
  end
end

spec/factories/categories.rb

FactoryBot.define do
  factory :category do
    sequence(:name) { |n| "name#{n}" }
    sequence(:branch) { |n| "branch#{n}" }
    
  end
end

categoryがnilなのがダメかと思いfactoryの内容を変更してみたりしましたが分かりませんでした。何かアドバイスあれがお願いいたします。

Answer 1

PostというのはCategoryの子レコードですか？
おそらく紐付く親が存在していないのでエラーになっているのだと思います。