Implement epics index action

app/controllers/concerns/issuable_collections.rb

@@ -143,6 +143,8 @@ module IssuableCollections
                            'Issue'
                          when MergeRequestsFinder
                            'MergeRequest'
+                         when EpicsFinder
+                           'Epic'
                          end
   end
 
@@ -155,6 +157,8 @@ module IssuableCollections
                                     :source_project, :target_project, :author, :assignee, :labels, :milestone,
                                     head_pipeline: :project, target_project: :namespace, merge_request_diff: :merge_request_diff_commits
                                   ]
+                                when 'Epic'
+                                  [:group, :author]
                                 end
   end
 end

config/application.rb

@@ -40,6 +40,7 @@ module Gitlab
     config.eager_load_paths.push(*%W[
       #{config.root}/ee/lib
       #{config.root}/ee/app/controllers
+      #{config.root}/ee/app/finders
       #{config.root}/ee/app/helpers
       #{config.root}/ee/app/mailers
       #{config.root}/ee/app/models

ee/app/controllers/groups/epics_controller.rb

 class Groups::EpicsController < Groups::ApplicationController
   include IssuableActions
+  include IssuableCollections
 
-  before_action :epic
+  before_action :epic, except: :index
+  before_action :set_issuables_index, only: :index
   before_action :authorize_update_issuable!, only: :update
 
   skip_before_action :labels
 
+  def index
+    @epics = @issuables
+
+    respond_to do |format|
+      format.html do
+        render 'groups/ee/epics/index'
+      end
+      format.json do
+        render json: {
+          html: view_to_html_string("groups/ee/epics/_epics")
+        }
+      end
+    end
+  end
+
   private
 
   def epic
@@ -41,4 +58,8 @@ class Groups::EpicsController < Groups::ApplicationController
   def show_view
     'groups/ee/epics/show'
   end
+
+  def finder_type
+    EpicsFinder
+  end
 end

ee/app/finders/epics_finder.rb

+class EpicsFinder < IssuableFinder
+  def klass
+    Epic
+  end
+
+  def execute
+    raise ArgumentError, 'group_id argument is missing' unless group
+
+    items = init_collection
+    items = by_created_at(items)
+    items = by_search(items)
+    items = by_author(items)
+    items = by_iids(items)
+
+    sort(items)
+  end
+
+  def row_count
+    execute.count
+  end
+
+  def group
+    return nil unless params[:group_id]
+    return @group if defined?(@group)
+
+    group = Group.find(params[:group_id])
+    group = nil unless Ability.allowed?(current_user, :read_epic, group)
+
+    @group = group
+  end
+
+  def init_collection
+    group.epics
+  end
+end

ee/app/views/groups/ee/epics/_epics.html.haml

+%ul.content-list.issues-list.issuable-list

ee/app/views/groups/ee/epics/index.html.haml

+- page_title "Epics"
+

spec/ee/spec/controllers/groups/epics_controller_spec.rb

@@ -9,6 +9,42 @@ describe Groups::EpicsController do
     sign_in(user)
   end
 
+  describe "GET #index" do
+    let!(:epic_list) { create_list(:epic, 2, group: group) }
+
+    before do
+      sign_in(user)
+      group.add_developer(user)
+    end
+
+    it "returns index" do
+      get :index, group_id: group
+
+      expect(response).to have_gitlab_http_status(200)
+    end
+
+    context 'with page param' do
+      let(:last_page) { group.epics.page.total_pages }
+
+      before do
+        allow(Kaminari.config).to receive(:default_per_page).and_return(1)
+      end
+
+      it 'redirects to last_page if page number is larger than number of pages' do
+        get :index, group_id: group, page: (last_page + 1).to_param
+
+        expect(response).to redirect_to(group_epics_path(page: last_page, state: controller.params[:state], scope: controller.params[:scope]))
+      end
+
+      it 'renders the specified page' do
+        get :index, group_id: group, page: last_page.to_param
+
+        expect(assigns(:epics).current_page).to eq(last_page)
+        expect(response).to have_gitlab_http_status(200)
+      end
+    end
+  end
+
   describe 'GET #show' do
     def show_epic(format = :html)
       get :show, group_id: group, id: epic.to_param, format: format

spec/ee/spec/finders/epics_finder_spec.rb

+require 'spec_helper'
+
+describe EpicsFinder do
+  let(:user) { create(:user)  }
+  let(:search_user) { create(:user)  }
+  let(:group) { create(:group, :private) }
+  let(:another_group) { create(:group) }
+  let!(:epic1) { create(:epic, group: group, title: 'This is awesome epic', created_at: 1.week.ago) }
+  let!(:epic2) { create(:epic, group: group, created_at: 4.days.ago, author: user) }
+  let!(:epic3) { create(:epic, group: group, description: 'not so awesome') }
+  let!(:epic4) { create(:epic, group: another_group) }
+
+  describe '#execute' do
+    def epics(params = {})
+      params[:group_id] = group.id
+
+      described_class.new(search_user, params).execute
+    end
+
+    context 'without param' do
+      it 'raises an error when group_id param is missing' do
+        expect { described_class.new(search_user).execute }.to raise_error { ArgumentError }
+      end
+    end
+
+    context 'when user can not read epics of a group' do
+      it 'raises an error when group_id param is missing' do
+        expect { epics }.to raise_error { ArgumentError }
+      end
+    end
+
+    context 'wtih correct params' do
+      before do
+        group.add_developer(search_user)
+      end
+
+      it 'returns all epics that belong to the given group' do
+        expect(epics).to contain_exactly(epic1, epic2, epic3)
+      end
+
+      context 'by created_at' do
+        it 'returns all epics created before the given date' do
+          expect(epics(created_before: 2.days.ago)).to contain_exactly(epic1, epic2)
+        end
+
+        it 'returns all epics created after the given date' do
+          expect(epics(created_after: 2.days.ago)).to contain_exactly(epic3)
+        end
+
+        it 'returns all epics created within the given interval' do
+          expect(epics(created_after: 5.days.ago, created_before: 1.day.ago)).to contain_exactly(epic2)
+        end
+      end
+
+      context 'by search' do
+        it 'returns all epics that match the search' do
+          expect(epics(search: 'awesome')).to contain_exactly(epic1, epic3)
+        end
+      end
+
+      context 'by author' do
+        it 'returns all epics authored by the given user' do
+          expect(epics(author_id: user.id)).to contain_exactly(epic2)
+        end
+      end
+
+      context 'by iids' do
+        it 'returns all epics by the given iids' do
+          expect(epics(iids: [epic1.iid, epic3.iid])).to contain_exactly(epic1, epic3)
+        end
+      end
+    end
+  end
+end