如何测试模型实例方法？

Question

我在实施 Rspec 时遇到了一些麻烦。我有三个模型； Post、Tagging 和 Tag。

app/models/tag.rb

class Tag < ApplicationRecord
  # associations
  has_many :taggings
  has_many :posts, through: :taggings

  # validations
  validates :name, presence: true, uniqueness: { case_sensitive: false }

  # returns a list of posts that are belonging to tag.
  def posts
      ...
  end
end

我能够为关联和验证编写规范，但坚持为 def posts ... end 的实例方法编写规范。有人可以简要解释如何编写此规范吗？我是 Rspec 的新手，所以请多多包涵。

spec/models/tag_spec.rb

require 'rails_helper'

RSpec.describe Tag, type: :model do
  describe "Associations" do
    it { should have_many(:posts).through(:taggings) }
  end

  describe "Validations" do
    subject { FactoryBot.create(:tag) }

    it { should validate_presence_of(:name) }
    it { should validate_uniqueness_of(:name).case_insensitive }
  end

  describe "#posts" do
    # need help
  end

end

Answer 1

你可以这样做：

describe '#posts' do
  before do
    let(:tag) { Tag.create(some_attribute: 'some_value') }
    let(:tagging) { Tagging.create(tag: tag, some_attribute: 'some_value') }
  end

  it "tag should do something" do
    expect(tag.posts).to eq('something')
  end

  it "tagging should do something" do
    expect(tagging.something).to eq('something')
  end

end

这将允许您在 Tag 上测试实例方法。基本上，您想在 before 块中构建要测试的对象，并在 it 块中调用它们的实例方法。

如何测试模型实例方法？

How to test a model instance method?

rspec

ruby-on-rails

rspec-rails

app/models/tag.rb

spec/models/tag_spec.rb