Refine based on review feedback

backend:
- add empty show method to controller
- add before_actions to controller for authorization
- add specs for controller and policy

frontend:
- use gl-button class
- pass parameters for download path

docs:
- add introduced line on group page
- clarify and reorder CSV description

doc/user/group/index.md

@@ -742,6 +742,8 @@ With [GitLab Issue Analytics](issues_analytics/index.md), you can see a bar char
 
 ## Repositories analytics **(PREMIUM)**
 
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/215104) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.4.
+
 With [GitLab Repositories Analytics](repositories_analytics/index.md), you can download a CSV of the latest coverage data for all the projects in your group.
 
 ## Dependency Proxy **(PREMIUM)**

doc/user/group/repositories_analytics/index.md

@@ -7,17 +7,19 @@ info: To determine the technical writer assigned to the Stage/Group associated w
 
 # Repositories Analytics **(PREMIUM)**
 
-> - [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/215104) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.3.
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/215104) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.4.
 
-To get a CSV of the code coverage data for all of the projects in your group, go to your group's **Analytics > CI/CD** page
+To get a CSV of the code coverage data for all of the projects in your group, go to your group's **Analytics > CI/CD** page, and click **Download historic test coverage data (.csv)**.
 
-Each row in the provided CSV includes:
+For each day that a coverage report was generated by a job in a project's pipeline, there will be a row in the CSV which includes:
 
-- The date when the coverage was calculated (at most one per day, from the latest run that day)
-- The name of the project
+- The date when the coverage job ran
 - The name of the job that generated the coverage report
+- The name of the project
 - The coverage value
 
+If the project's code coverage was calculated more than once in a day, we will take the last value from that day.
+
 <!-- ## Troubleshooting
 
 Include any troubleshooting steps that you can foresee. If you know beforehand what issues

ee/app/controllers/groups/analytics/repository_analytics_controller.rb

 # frozen_string_literal: true
 
 class Groups::Analytics::RepositoryAnalyticsController < Groups::Analytics::ApplicationController
+  layout 'group'
+
+  before_action :load_group
+  before_action -> { check_feature_availability!(:group_coverage_reports) }
+  before_action -> { check_feature_availability!(:group_repository_analytics) }
+  before_action -> { authorize_view_by_action!(:read_group_repository_analytics) }
+
+  def show
+  end
 end

ee/app/helpers/ee/groups_helper.rb

@@ -118,7 +118,7 @@ module EE
     def get_group_sidebar_links
       links = super
 
-      resources = [:cycle_analytics, :merge_request_analytics]
+      resources = [:cycle_analytics, :merge_request_analytics, :repository_analytics]
 
       links += resources.select do |resource|
         can?(current_user, "read_group_#{resource}".to_sym, @group)
@@ -148,10 +148,6 @@ module EE
         links << :iterations
       end
 
-      if @group.feature_available?(:group_repositories_analytics) && can?(current_user, :read_group_repositories_analytics, @group)
-        links << :repositories_analytics
-      end
-
       links
     end
   end

ee/app/views/groups/analytics/repository_analytics/show.html.haml

@@ -7,4 +7,5 @@
 .d-flex.justify-content-between.align-items-center
   %h4.sub-header
     = _("Test Code Coverage")
-  = link_to _("Download historic test coverage data (.csv)"), group_analytics_coverage_reports_path(@group, format: :csv), class: 'btn btn-sm'
+  = link_to _("Download historic test coverage data (.csv)"), group_analytics_coverage_reports_path(@group, format: :csv, ref_path: "refs/heads/master", start_date: Date.today - 1.year, end_date: Date.today),
+      rel: 'nofollow', download: '', method: :get, class: 'gl-button btn-sm'

ee/spec/controllers/groups/analytics/repository_analytics_controller_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Groups::Analytics::RepositoryAnalyticsController do
+  let_it_be(:current_user) { create(:user) }
+  let_it_be(:group) { create :group }
+  let_it_be(:feature_name) { :group_repository_analytics }
+
+  before do
+    sign_in(current_user)
+
+    stub_licensed_features(feature_name => true)
+  end
+
+  describe 'GET show' do
+    subject { get :show, params: { group_id: group } }
+
+    before do
+      group.add_guest(current_user)
+    end
+
+    it { is_expected.to be_successful }
+
+    context 'when license is missing' do
+      before do
+        stub_licensed_features(feature_name => false)
+      end
+
+      it { is_expected.to have_gitlab_http_status(:forbidden) }
+    end
+
+    context 'when the user has no access to the group' do
+      before do
+        current_user.group_members.delete_all
+      end
+
+      it { is_expected.to have_gitlab_http_status(:forbidden) }
+    end
+  end
+end

ee/spec/policies/group_policy_spec.rb

@@ -194,6 +194,26 @@ RSpec.describe GroupPolicy do
     it { is_expected.not_to be_allowed(:read_group_activity_analytics) }
   end
 
+  context 'when group repository analytics is available' do
+    let(:current_user) { guest }
+
+    before do
+      stub_licensed_features(group_repository_analytics: true)
+    end
+
+    it { is_expected.to be_allowed(:read_group_repository_analytics) }
+  end
+
+  context 'when group repository analytics is not available' do
+    let(:current_user) { guest }
+
+    before do
+      stub_licensed_features(group_repository_analytics: false)
+    end
+
+    it { is_expected.not_to be_allowed(:read_group_repository_analytics) }
+  end
+
   context 'when timelogs report feature is enabled' do
     before do
       stub_licensed_features(group_timelogs: true)