variant_association.rb

module Algolia
  module Factory
    class VariantAssociation
      def initialize(association, mapper=nil)
        @association = association
        @mapper = mapper || Mapper::Variant.new
      end

      def build
        objects = association.variants.map do |variant|
          mapper.map(variant)
        end

        ObjectList.new(*objects)
      end

      private
      attr_reader :association, :mapper
    end
  end
end

variant_association_spec.rb

require 'spec_helper'

describe Algolia::Factory::VariantAssociation do
  describe "#build" do
    it "returns a list of mapped variants" do
      mapper = instance_double(Algolia::Mapper::Variant)
      variant_one, variant_two = double(Variant), double(Variant)
      association = double('association', variants: [variant_one, variant_two])
      map_one, map_two = double('mapped variant one'), double('mapped variant two')

      allow(mapper).to receive(:map).once.with(variant_one).and_return(map_one)
      allow(mapper).to receive(:map).once.with(variant_two).and_return(map_two)

      result = described_class.new(association, mapper).build

      expect(result).to be_a(Algolia::ObjectList)
      expect(result).to match_array([map_one,map_two])
    end
  end
end