discourse/spec/models/topic_posters_summary_spec.rb

require 'rails_helper'

describe TopicPostersSummary do
  describe '#summary' do
    let(:summary) { described_class.new(topic).summary }

    let(:topic) do
      Fabricate(:topic,
        user: topic_creator,
        last_poster: last_poster,
        featured_user1: featured_user1,
        featured_user2: featured_user2,
        featured_user3: featured_user3,
        featured_user4: featured_user4
      )
    end

    let(:topic_creator)  { Fabricate(:user) }
    let(:last_poster)    { nil }
    let(:featured_user1) { nil }
    let(:featured_user2) { nil }
    let(:featured_user3) { nil }
    let(:featured_user4) { nil }

    it 'contains only the topic creator when there are no other posters' do
      expect(summary.count).to eq 1

      summary.first.tap do |topic_poster|
        expect(topic_poster.user).to eq topic_creator
        expect(topic_poster.description).to eq(
          "#{I18n.t(:original_poster)}, #{I18n.t(:most_recent_poster)}"
        )
      end
    end

    context 'when the lastest poster is also the topic creator' do
      let(:last_poster)    { topic_creator }
      let(:featured_user1) { Fabricate(:user) }

      before do
        topic.last_poster = topic_creator
        topic.featured_user1 = featured_user1
        topic.save!
      end

      it 'keeps the topic creator at the front of the summary' do
        expect(summary.map(&:user)).to eq([
          topic_creator,
          featured_user1
        ])
      end
    end

    context 'when the topic has many posters' do
      let(:last_poster)    { Fabricate(:user) }
      let(:featured_user1) { Fabricate(:user) }
      let(:featured_user2) { Fabricate(:user) }
      let(:featured_user3) { Fabricate(:user) }
      let(:featured_user4) { Fabricate(:user) }

      it 'contains only five posters with latest poster at the end' do
        expect(summary.map(&:user)).to eq([
          topic_creator,
          featured_user1, featured_user2, featured_user3,
          last_poster
        ])
        # If more than one user, attach the latest class
        expect(summary.last.extras).to eq 'latest'
      end
    end
  end
end