Add epics list feature specs

spec/ee/spec/features/epics/epics_list_spec.rb

+require 'spec_helper'
+
+describe 'epics list', :js do
+  let(:group) { create(:group, :public) }
+  let(:user) { create(:user) }
+
+  before do
+    sign_in(user)
+  end
+
+  context 'when epics exist for the group' do
+    let!(:epics) { create_list(:epic, 2, group: group) }
+
+    before do
+      visit group_epics_path(group)
+    end
+
+    it 'shows the epics in the navigation sidebar' do
+      expect(first('.nav-sidebar  .active a .nav-item-name')).to have_content('Epics')
+      expect(first('.nav-sidebar .active a .count')).to have_content('2')
+    end
+
+    it 'renders the list correctly' do
+      page.within('.page-with-new-nav .content') do
+        expect(find('.top-area')).to have_content('All 2')
+        within('.issuable-list') do
+          expect(page).to have_content(epics.first.title)
+          expect(page).to have_content(epics.second.title)
+        end
+      end
+    end
+
+    it 'renders the epic detail correctly after clicking the link' do
+      page.within('.page-with-new-nav .content .issuable-list') do
+        click_link(epics.first.title)
+      end
+
+      wait_for_requests
+
+      expect(page.find('.issuable-details h2.title')).to have_content(epics.first.title)
+    end
+  end
+
+  context 'when no epics exist for the group' do
+    it 'renders the empty list page' do
+      visit group_epics_path(group)
+
+      within('#content-body') do
+        expect(find('.empty-state h4'))
+          .to have_content('Epics let you manage your portfolio of projects more efficiently and with less effort')
+      end
+    end
+  end
+end