Include recent failures data in test reports response

This affects the test_reports.json endpoint to include
the `recent_failures` data in each test case entity.

app/models/ci/test_case_failure.rb

@@ -4,9 +4,26 @@ module Ci
   class TestCaseFailure < ApplicationRecord
     extend Gitlab::Ci::Model
 
+    REPORT_WINDOW = 14.days
+
     validates :test_case, :build, :failed_at, presence: true
 
     belongs_to :test_case, class_name: "Ci::TestCase", foreign_key: :test_case_id
     belongs_to :build, class_name: "Ci::Build", foreign_key: :build_id
+
+    def self.recent_failures_count(project:, test_case_keys:, date_range: REPORT_WINDOW.ago..Time.current)
+      joins(:test_case)
+        .where(
+          ci_test_cases: {
+            project_id: project.id,
+            key_hash: test_case_keys
+          },
+          ci_test_case_failures: {
+            failed_at: date_range
+          }
+        )
+        .group(:key_hash)
+        .count('ci_test_case_failures.id')
+    end
   end
 end

app/serializers/test_case_entity.rb

@@ -10,6 +10,7 @@ class TestCaseEntity < Grape::Entity
   expose :execution_time
   expose :system_output
   expose :stack_trace
+  expose :recent_failures
   expose :attachment_url, if: -> (*) { can_read_screenshots? } do |test_case|
     expose_url(test_case.attachment_url)
   end

app/services/ci/compare_test_reports_service.rb

@@ -13,5 +13,16 @@ module Ci
     def get_report(pipeline)
       pipeline&.test_reports
     end
+
+    def build_comparer(base_pipeline, head_pipeline)
+      base_report = get_report(base_pipeline)
+      head_report = get_report(head_pipeline)
+
+      # We need to load the test failure history for the head report because we display
+      # this on the MR widget
+      ::Gitlab::Ci::Reports::TestReportFailureHistory.new(head_report, project).load!
+
+      comparer_class.new(base_report, head_report)
+    end
   end
 end

lib/gitlab/ci/reports/test_case.rb

@@ -10,7 +10,7 @@ module Gitlab
         STATUS_ERROR = 'error'
         STATUS_TYPES = [STATUS_ERROR, STATUS_FAILED, STATUS_SUCCESS, STATUS_SKIPPED].freeze
 
-        attr_reader :suite_name, :name, :classname, :execution_time, :status, :file, :system_output, :stack_trace, :key, :attachment, :job
+        attr_reader :suite_name, :name, :classname, :execution_time, :status, :file, :system_output, :stack_trace, :key, :attachment, :job, :recent_failures
 
         def initialize(params)
           @suite_name = params.fetch(:suite_name)
@@ -24,9 +24,15 @@ module Gitlab
           @attachment = params.fetch(:attachment, nil)
           @job = params.fetch(:job, nil)
 
+          @recent_failures = nil
+
           @key = hash_key("#{suite_name}_#{classname}_#{name}")
         end
 
+        def set_recent_failures(count, base_branch)
+          @recent_failures = { count: count, base_branch: base_branch }
+        end
+
         def has_attachment?
           attachment.present?
         end

lib/gitlab/ci/reports/test_report_failure_history.rb

+# frozen_string_literal: true
+
+module Gitlab
+  module Ci
+    module Reports
+      class TestReportFailureHistory
+        include Gitlab::Utils::StrongMemoize
+
+        def initialize(report, project)
+          @report = report
+          @project = project
+        end
+
+        def load!
+          return unless Feature.enabled?(:test_failure_history, project)
+
+          recent_failures_count.each do |key_hash, count|
+            failed_test_cases[key_hash].set_recent_failures(count, project.default_branch_or_master)
+          end
+        end
+
+        private
+
+        attr_reader :report, :project
+
+        def recent_failures_count
+          ::Ci::TestCaseFailure.recent_failures_count(
+            project: project,
+            test_case_keys: failed_test_cases.keys
+          )
+        end
+
+        def failed_test_cases
+          strong_memoize(:failed_test_cases) do
+            report.failed_test_cases
+          end
+        end
+      end
+    end
+  end
+end

lib/gitlab/ci/reports/test_reports.rb

@@ -52,6 +52,14 @@ module Gitlab
             test_suites.values.sum { |suite| suite.public_send("#{status_type}_count") } # rubocop:disable GitlabSecurity/PublicSend
             # rubocop: enable CodeReuse/ActiveRecord
           end
+
+          define_method("#{status_type}_test_cases") do
+            {}.tap do |hash|
+              test_suites.values.each do |test_suite|
+                hash.merge!(test_suite.public_send(status_type)) # rubocop:disable GitlabSecurity/PublicSend
+              end
+            end
+          end
         end
       end
     end

spec/fixtures/api/schemas/entities/test_case.json

@@ -12,7 +12,13 @@
     "execution_time": { "type": "float" },
     "system_output": { "type": ["string", "null"] },
     "stack_trace":  { "type": ["string", "null"] },
-    "attachment_url":  { "type": ["string", "null"] }
+    "attachment_url":  { "type": ["string", "null"] },
+    "recent_failures": {
+      "oneOf": [
+        { "type": "null" },
+        { "$ref": "test_case/recent_failures.json" }
+      ]
+    }
   },
   "additionalProperties": false
 }

spec/fixtures/api/schemas/entities/test_case/recent_failures.json

+{
+  "type": "object",
+  "required": [
+    "count",
+    "base_branch"
+  ],
+  "properties": {
+    "count": { "type": "integer" },
+    "base_branch": { "type": "string" }
+  },
+  "additionalProperties": false
+}

spec/lib/gitlab/ci/reports/test_case_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe Gitlab::Ci::Reports::TestCase do
+RSpec.describe Gitlab::Ci::Reports::TestCase, :aggregate_failures do
   describe '#initialize' do
     let(:test_case) { described_class.new(params) }
 
@@ -82,4 +82,17 @@ RSpec.describe Gitlab::Ci::Reports::TestCase do
       end
     end
   end
+
+  describe '#set_recent_failures' do
+    it 'sets the recent_failures information' do
+      test_case = build(:report_test_case)
+
+      test_case.set_recent_failures(1, 'master')
+
+      expect(test_case.recent_failures).to eq(
+        count: 1,
+        base_branch: 'master'
+      )
+    end
+  end
 end

spec/lib/gitlab/ci/reports/test_report_failure_history_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Ci::Reports::TestReportFailureHistory, :aggregate_failures do
+  include TestReportsHelper
+
+  describe '#load!' do
+    let_it_be(:project) { create(:project) }
+    let(:test_reports) { Gitlab::Ci::Reports::TestReports.new }
+    let(:failed_rspec) { create_test_case_rspec_failed }
+    let(:failed_java) { create_test_case_java_failed }
+
+    subject(:load_history) { described_class.new(test_reports, project).load! }
+
+    before do
+      test_reports.get_suite('rspec').add_test_case(failed_rspec)
+      test_reports.get_suite('java').add_test_case(failed_java)
+
+      allow(Ci::TestCaseFailure)
+        .to receive(:recent_failures_count)
+        .with(project: project, test_case_keys: [failed_rspec.key, failed_java.key])
+        .and_return(
+          failed_rspec.key => 2,
+          failed_java.key => 1
+        )
+    end
+
+    it 'sets the recent failures for each matching failed test case in all test suites' do
+      load_history
+
+      expect(failed_rspec.recent_failures).to eq(count: 2, base_branch: 'master')
+      expect(failed_java.recent_failures).to eq(count: 1, base_branch: 'master')
+    end
+
+    context 'when feature flag is disabled' do
+      before do
+        stub_feature_flags(test_failure_history: false)
+      end
+
+      it 'does not set recent failures' do
+        load_history
+
+        expect(failed_rspec.recent_failures).to be_nil
+        expect(failed_java.recent_failures).to be_nil
+      end
+    end
+  end
+end

spec/lib/gitlab/ci/reports/test_reports_spec.rb

@@ -185,5 +185,30 @@ RSpec.describe Gitlab::Ci::Reports::TestReports do
         end
       end
     end
+
+    describe "##{status_type}_test_cases" do
+      subject { test_reports.public_send("#{status_type}_test_cases") }
+
+      context "when #{status_type} test case exists" do
+        it 'returns the test cases' do
+          rspec_case = public_send("create_test_case_rspec_#{status_type}")
+          java_case = public_send("create_test_case_java_#{status_type}")
+
+          test_reports.get_suite('rspec').add_test_case(rspec_case)
+          test_reports.get_suite('junit').add_test_case(java_case)
+
+          is_expected.to eq(
+            rspec_case.key => rspec_case,
+            java_case.key => java_case
+          )
+        end
+      end
+
+      context "when #{status_type} test case do not exist" do
+        it 'returns nothing' do
+          is_expected.to eq({})
+        end
+      end
+    end
   end
 end

spec/models/ci/test_case_failure_spec.rb

@@ -15,4 +15,59 @@ RSpec.describe Ci::TestCaseFailure do
     it { is_expected.to validate_presence_of(:build) }
     it { is_expected.to validate_presence_of(:failed_at) }
   end
+
+  describe '.recent_failures_count' do
+    let_it_be(:project) { create(:project) }
+
+    subject(:recent_failures) do
+      described_class.recent_failures_count(
+        project: project,
+        test_case_keys: test_case_keys
+      )
+    end
+
+    context 'when test case failures are within the date range and are for the test case keys' do
+      let(:tc_1) { create(:ci_test_case, project: project) }
+      let(:tc_2) { create(:ci_test_case, project: project) }
+      let(:test_case_keys) { [tc_1.key_hash, tc_2.key_hash] }
+
+      before do
+        create_list(:ci_test_case_failure, 3, test_case: tc_1, failed_at: 1.day.ago)
+        create_list(:ci_test_case_failure, 2, test_case: tc_2, failed_at: 3.days.ago)
+      end
+
+      it 'returns the number of failures for each test case key hash for the past 14 days by default' do
+        expect(recent_failures).to eq(
+          tc_1.key_hash => 3,
+          tc_2.key_hash => 2
+        )
+      end
+    end
+
+    context 'when test case failures are within the date range but are not for the test case keys' do
+      let(:tc) { create(:ci_test_case, project: project) }
+      let(:test_case_keys) { ['some-other-key-hash'] }
+
+      before do
+        create(:ci_test_case_failure, test_case: tc, failed_at: 1.day.ago)
+      end
+
+      it 'excludes them from the count' do
+        expect(recent_failures[tc.key_hash]).to be_nil
+      end
+    end
+
+    context 'when test case failures are not within the date range but are for the test case keys' do
+      let(:tc) { create(:ci_test_case, project: project) }
+      let(:test_case_keys) { [tc.key_hash] }
+
+      before do
+        create(:ci_test_case_failure, test_case: tc, failed_at: 15.days.ago)
+      end
+
+      it 'excludes them from the count' do
+        expect(recent_failures[tc.key_hash]).to be_nil
+      end
+    end
+  end
 end

spec/serializers/test_case_entity_spec.rb

@@ -27,12 +27,17 @@ RSpec.describe TestCaseEntity do
     context 'when test case is failed' do
       let(:test_case) { create_test_case_rspec_failed }
 
+      before do
+        test_case.set_recent_failures(3, 'master')
+      end
+
       it 'contains correct test case details' do
         expect(subject[:status]).to eq('failed')
         expect(subject[:name]).to eq('Test#sum when a is 1 and b is 3 returns summary')
         expect(subject[:classname]).to eq('spec.test_spec')
         expect(subject[:file]).to eq('./spec/test_spec.rb')
         expect(subject[:execution_time]).to eq(2.22)
+        expect(subject[:recent_failures]).to eq({ count: 3, base_branch: 'master' })
       end
     end
 

spec/services/ci/compare_test_reports_service_spec.rb

@@ -44,6 +44,33 @@ RSpec.describe Ci::CompareTestReportsService do
         expect(subject.dig(:data, 'suites', 0, 'status') ).to eq('error')
       end
     end
+
+    context 'test failure history' do
+      let!(:base_pipeline) { nil }
+      let!(:head_pipeline) { create(:ci_pipeline, :with_test_reports, project: project) }
+
+      let(:recent_failures_per_test_case) do
+        subject.dig(:data, 'suites', 0, 'new_failures').map { |f| f['recent_failures'] }
+      end
+
+      # Create test case failure records based on the head pipeline build
+      before do
+        build = head_pipeline.builds.last
+        build.update_column(:finished_at, 1.day.ago) # Just to be sure we are included in the report window
+
+        # The JUnit fixture for the given build has 2 failures.
+        # This service will create 1 test case failure record for each.
+        Ci::TestCasesService.new.execute(build)
+      end
+
+      it 'loads on the report', :aggregate_failures do
+        expect(subject[:data]).to match_schema('entities/test_reports_comparer')
+        expect(recent_failures_per_test_case).to eq([
+          { 'count' => 1, 'base_branch' => 'master' },
+          { 'count' => 1, 'base_branch' => 'master' }
+        ])
+      end
+    end
   end
 
   describe '#latest?' do