discourse/spec/requests/application_controller_spec.rb

require 'rails_helper'

RSpec.describe ApplicationController do
  describe '#redirect_to_login_if_required' do
    let(:admin) { Fabricate(:admin) }

    before do
      admin  # to skip welcome wizard at home page `/`
      SiteSetting.login_required = true
    end

    it "should carry-forward authComplete param to login page redirect" do
      get "/?authComplete=true"
      expect(response).to redirect_to('/login?authComplete=true')
    end
  end

  describe 'build_not_found_page' do
    describe 'topic not found' do
      it 'should return 404 and show Google search' do
        get "/t/nope-nope/99999999"
        expect(response.status).to eq(404)
        expect(response.body).to include(I18n.t('page_not_found.search_google'))
      end

      it 'should not include Google search if login_required is enabled' do
        SiteSetting.login_required = true
        sign_in(Fabricate(:user))
        get "/t/nope-nope/99999999"
        expect(response.status).to eq(404)
        expect(response.body).to_not include('google.com/search')
      end
    end
  end
end