Empty diff in rspec test

download_stats_service_spec.rb

describe 'self.index_download_stats' do
    let(:stat_1) {Stat.create mobile_application_id: update_1.mobile_application.id,
                              store_id: store.id,
                              user_id: store.users[0].id,
                              mobile_application_update_id: update_1.id,
                              version: 1,
                              action: 'download',
                              created_at: 2.day.ago}
    let(:stat_2) {Stat.create mobile_application_id: update_1.mobile_application.id,
                              store_id: store.id,
                              user_id: store.users[0].id,
                              mobile_application_update_id: update_1.id,
                              version: 1,
                              action: 'download',
                              created_at: 3.day.ago}
    let(:stat_3) {Stat.create mobile_application_id: update_1.mobile_application.id,
                              store_id: store.id,
                              user_id: store.users[0].id,
                              mobile_application_update_id: update_1.id,
                              version: 1,
                              action: 'download',
                              created_at: 16.day.ago}
    let(:json_1) {stat_1.as_json(except: [:_id, :indexed])}
    let(:json_2) {stat_2.as_json(except: [:_id, :indexed])}
    let(:json_3) {stat_3.as_json(except: [:_id, :indexed])}

    before do
      json_1['id'] = stat_1.id.to_s
      json_2['id'] = stat_2.id.to_s
      json_3['id'] = stat_3.id.to_s
    end
    
    before do
      # prints to check time equality
      p json_1['created_at'] == stat_1.created_at
      p json_1['updated_at'] == stat_1.updated_at
    end

    before { expect(ElasticSearchUtils).to receive(:index_stat).with(:download, json_1).once }

    subject { DownloadStatsService.index_download_stats }

    it { subject }
  end