Fix group coverage for default branch

This commits fixes a bug where the group code coverage data was not
being rendered correctly if the default branch was not master.

app/finders/ci/daily_build_group_report_results_finder.rb

@@ -4,7 +4,7 @@ module Ci
   class DailyBuildGroupReportResultsFinder
     include Gitlab::Allowable
 
-    def initialize(current_user:, project:, ref_path:, start_date:, end_date:, limit: nil)
+    def initialize(current_user:, project:, ref_path: nil, start_date:, end_date:, limit: nil)
       @current_user = current_user
       @project = project
       @ref_path = ref_path
@@ -35,11 +35,18 @@ module Ci
     end
 
     def query_params
-      {
+      params = {
         project_id: project,
-        ref_path: ref_path,
         date: start_date..end_date
       }
+
+      if ref_path
+        params[:ref_path] = ref_path
+      else
+        params[:default_branch] = true
+      end
+
+      params
     end
 
     def none

doc/user/group/repositories_analytics/index.md

@@ -25,7 +25,9 @@ To see the latest code coverage for each project in your group:
 
 > [Introduced](https://gitlab.com/gitlab-org/gitlab/-/issues/215104) in [GitLab Premium](https://about.gitlab.com/pricing/) 13.4.
 
-You can get a CSV of the code coverage data for all of the projects in your group. This report has a maximum of 1000 records. To get the report:
+You can get a CSV of the code coverage data for all of the projects in your group. This report has a maximum of 1000 records. The code coverage data is from the default branch in each project.
+
+To get the report:
 
 1. Go to your group's **Analytics > Repositories** page
 1. Click **Download historic test coverage data (.csv)**,
@@ -44,6 +46,9 @@ For each day that a coverage report was generated by a job in a project's pipeli
 
 If the project's code coverage was calculated more than once in a day, we will take the last value from that day.
 
+NOTE:
+[In GitLab 13.7 and later](https://gitlab.com/gitlab-org/gitlab/-/issues/270102), group code coverage data is taken from the configured [default branch](../../project/repository/branches/index.md#default-branch). In earlier versions, it is taken from the `master` branch.
+
 <!-- ## Troubleshooting
 
 Include any troubleshooting steps that you can foresee. If you know beforehand what issues

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

@@ -40,7 +40,7 @@ class Groups::Analytics::CoverageReportsController < Groups::Analytics::Applicat
       current_user: current_user,
       group: @group,
       project_ids: params.permit(project_ids: [])[:project_ids],
-      ref_path: params.require(:ref_path),
+      ref_path: params[:ref_path],
       start_date: Date.parse(params.require(:start_date)),
       end_date: Date.parse(params.require(:end_date))
     }

ee/app/finders/ci/daily_build_group_report_results_by_group_finder.rb

@@ -9,7 +9,7 @@ module Ci
     # See thread: https://gitlab.com/gitlab-org/gitlab/-/merge_requests/37768#note_386839633
     GROUP_QUERY_RESULT_LIMIT = 1000.freeze
 
-    def initialize(current_user:, group:, project_ids: [], ref_path:, start_date:, end_date:, limit: nil)
+    def initialize(current_user:, group:, project_ids: [], ref_path: nil, start_date:, end_date:, limit: nil)
       super(current_user: current_user, project: nil, ref_path: ref_path, start_date: start_date, end_date: end_date, limit: limit)
 
       @group = group

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

@@ -4,5 +4,5 @@
   %h3
     = _("Repositories Analytics")
 
-#js-group-repository-analytics{ data: { group_analytics_coverage_reports_path: group_analytics_coverage_reports_path(@group, format: :csv, ref_path: "refs/heads/master"),
+#js-group-repository-analytics{ data: { group_analytics_coverage_reports_path: group_analytics_coverage_reports_path(@group, format: :csv),
   group_full_path: @group.full_path } }

ee/changelogs/unreleased/mo-fix-group-coverage-for-default-branch.yml

+---
+title: Fix group code coverage for default branch
+merge_request: 49630
+author:
+type: fixed

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

@@ -94,6 +94,17 @@ RSpec.describe Groups::Analytics::CoverageReportsController do
         end
       end
 
+      context 'when ref_path is nil' do
+        let(:ref_path) { nil }
+
+        it 'responds HTTP 200' do
+          get :index, params: valid_request_params
+
+          expect(response).to have_gitlab_http_status(:ok)
+          expect(csv_response.size).to eq(3)
+        end
+      end
+
       it 'executes the same number of queries regardless of the number of records returned' do
         control = ActiveRecord::QueryRecorder.new do
           get :index, params: valid_request_params

spec/finders/ci/daily_build_group_report_results_finder_spec.rb

@@ -4,57 +4,77 @@ require 'spec_helper'
 
 RSpec.describe Ci::DailyBuildGroupReportResultsFinder do
   describe '#execute' do
-    let(:project) { create(:project, :private) }
-    let(:ref_path) { 'refs/heads/master' }
+    let_it_be(:project) { create(:project, :private) }
+    let_it_be(:current_user) { project.owner }
+    let_it_be(:ref_path) { 'refs/heads/master' }
     let(:limit) { nil }
+    let_it_be(:default_branch) { false }
 
-    let!(:rspec_coverage_1) { create_daily_coverage('rspec', 79.0, '2020-03-09') }
-    let!(:karma_coverage_1) { create_daily_coverage('karma', 89.0, '2020-03-09') }
-    let!(:rspec_coverage_2) { create_daily_coverage('rspec', 95.0, '2020-03-10') }
-    let!(:karma_coverage_2) { create_daily_coverage('karma', 92.0, '2020-03-10') }
-    let!(:rspec_coverage_3) { create_daily_coverage('rspec', 97.0, '2020-03-11') }
-    let!(:karma_coverage_3) { create_daily_coverage('karma', 99.0, '2020-03-11') }
+    let_it_be(:rspec_coverage_1) { create_daily_coverage('rspec', 79.0, '2020-03-09') }
+    let_it_be(:karma_coverage_1) { create_daily_coverage('karma', 89.0, '2020-03-09') }
+    let_it_be(:rspec_coverage_2) { create_daily_coverage('rspec', 95.0, '2020-03-10') }
+    let_it_be(:karma_coverage_2) { create_daily_coverage('karma', 92.0, '2020-03-10') }
+    let_it_be(:rspec_coverage_3) { create_daily_coverage('rspec', 97.0, '2020-03-11') }
+    let_it_be(:karma_coverage_3) { create_daily_coverage('karma', 99.0, '2020-03-11') }
 
-    subject do
-      described_class.new(
+    let(:attributes) do
+      {
         current_user: current_user,
         project: project,
         ref_path: ref_path,
         start_date: '2020-03-09',
         end_date: '2020-03-10',
         limit: limit
-      ).execute
+      }
     end
 
-    context 'when current user is allowed to read build report results' do
-      let(:current_user) { project.owner }
+    subject(:coverages) do
+      described_class.new(**attributes).execute
+    end
+
+    context 'when ref_path is present' do
+      context 'when current user is allowed to read build report results' do
+        it 'returns all matching results within the given date range' do
+          expect(coverages).to match_array([
+            karma_coverage_2,
+            rspec_coverage_2,
+            karma_coverage_1,
+            rspec_coverage_1
+          ])
+        end
+
+        context 'and limit is specified' do
+          let(:limit) { 2 }
 
-      it 'returns all matching results within the given date range' do
-        expect(subject).to match_array([
-          karma_coverage_2,
-          rspec_coverage_2,
-          karma_coverage_1,
-          rspec_coverage_1
-        ])
+          it 'returns limited number of matching results within the given date range' do
+            expect(coverages).to match_array([
+              karma_coverage_2,
+              rspec_coverage_2
+            ])
+          end
+        end
       end
 
-      context 'and limit is specified' do
-        let(:limit) { 2 }
+      context 'when current user is not allowed to read build report results' do
+        let(:current_user) { create(:user) }
 
-        it 'returns limited number of matching results within the given date range' do
-          expect(subject).to match_array([
-            karma_coverage_2,
-            rspec_coverage_2
-          ])
+        it 'returns an empty result' do
+          expect(coverages).to be_empty
         end
       end
     end
 
-    context 'when current user is not allowed to read build report results' do
-      let(:current_user) { create(:user) }
+    context 'when ref_path is not present' do
+      let(:ref_path) { nil }
 
-      it 'returns an empty result' do
-        expect(subject).to be_empty
+      context 'when coverages exist for the default branch' do
+        let(:default_branch) { true }
+
+        it 'returns coverage for the default branch' do
+          rspec_coverage_4 = create_daily_coverage('rspec', 66.0, '2020-03-10')
+
+          expect(coverages).to contain_exactly(rspec_coverage_4)
+        end
       end
     end
   end
@@ -65,10 +85,11 @@ RSpec.describe Ci::DailyBuildGroupReportResultsFinder do
     create(
       :ci_daily_build_group_report_result,
       project: project,
-      ref_path: ref_path,
+      ref_path: ref_path || 'feature-branch',
       group_name: group_name,
       data: { 'coverage' => coverage },
-      date: date
+      date: date,
+      default_branch: default_branch
     )
   end
 end