Repository pattern spec example in Ruby for Rails developers

7_brand_in_memory_adapter.rb

class BrandInMemoryAdapter
  attr_accessor :db

  def initialize
    @db = []
  end

  def all
    db
  end
end

8_get_all_brands_spec.rb

RSpec.describe QueryObjects::GetAllBrands do
  let(:adapter)    { BrandInMemoryAdapter.new }
  let(:repository) { Repositories::BrandRepository.new(adapter) }
  let(:subject)    { described_class.new(repository) }

  context 'No records in database' do
    it 'fetches all brands' do
      expect(subject.()).to eq []
    end
  end

  context 'Prefilled records in database' do
    let(:dummy_records) do
      10.times.map do
        OpenStruct.new(
          id:          SecureRandom.uuid,
          name:        Faker::Name.name,
          image:       "#{Faker::Internet.http_url}/image.png",
          description: Faker::Lorem.paragraph,
        )
      end
    end
    let(:index) { rand(dummy_records.length) }

    before { adapter.db = dummy_records }

    it 'fetches all brands' do
      record = subject.()[index]
      expect(record.id)         .to eq dummy_records[index].id
      expect(record.name)       .to eq dummy_records[index].name
      expect(record.image)      .to eq dummy_records[index].image
      expect(record.description).to eq dummy_records[index].description
    end
  end
end