Add compare_accessibility_report to MergeRequest

app/models/merge_request.rb

@@ -1317,6 +1317,14 @@ class MergeRequest < ApplicationRecord
     actual_head_pipeline&.has_reports?(Ci::JobArtifact.terraform_reports)
   end
 
+  def compare_accessibility_reports
+    unless has_accessibility_reports?
+      return { status: :error, status_reason: _('This merge request does not have accessibility reports') }
+    end
+
+    compare_reports(Ci::CompareAccessibilityReportsService)
+  end
+
   # TODO: this method and compare_test_reports use the same
   # result type, which is handled by the controller's #reports_response.
   # we should minimize mistakes by isolating the common parts.

locale/gitlab.pot

@@ -21626,6 +21626,9 @@ msgstr ""
 msgid "This means you can not push code until you create an empty repository or import existing one."
 msgstr ""
 
+msgid "This merge request does not have accessibility reports"
+msgstr ""
+
 msgid "This merge request is locked."
 msgstr ""
 

spec/models/merge_request_spec.rb

@@ -1889,6 +1889,62 @@ describe MergeRequest do
     end
   end
 
+  describe '#compare_accessibility_reports' do
+    let_it_be(:project) { create(:project, :repository) }
+    let_it_be(:merge_request, reload: true) { create(:merge_request, :with_accessibility_reports, source_project: project) }
+    let_it_be(:pipeline) { merge_request.head_pipeline }
+
+    subject { merge_request.compare_accessibility_reports }
+
+    context 'when head pipeline has accessibility reports' do
+      let(:job) do
+        create(:ci_build, options: { artifacts: { reports: { pa11y: ['accessibility.json'] } } }, pipeline: pipeline)
+      end
+
+      let(:artifacts_metadata) { create(:ci_job_artifact, :metadata, job: job) }
+
+      context 'when reactive cache worker is parsing results asynchronously' do
+        it 'returns parsing status' do
+          expect(subject[:status]).to eq(:parsing)
+        end
+      end
+
+      context 'when reactive cache worker is inline' do
+        before do
+          synchronous_reactive_cache(merge_request)
+        end
+
+        it 'returns parsed status' do
+          expect(subject[:status]).to eq(:parsed)
+          expect(subject[:data]).to be_present
+        end
+
+        context 'when an error occurrs' do
+          before do
+            merge_request.update!(head_pipeline: nil)
+          end
+
+          it 'returns an error status' do
+            expect(subject[:status]).to eq(:error)
+            expect(subject[:status_reason]).to eq("This merge request does not have accessibility reports")
+          end
+        end
+
+        context 'when cached result is not latest' do
+          before do
+            allow_next_instance_of(Ci::CompareAccessibilityReportsService) do |service|
+              allow(service).to receive(:latest?).and_return(false)
+            end
+          end
+
+          it 'raises an InvalidateReactiveCache error' do
+            expect { subject }.to raise_error(ReactiveCaching::InvalidateReactiveCache)
+          end
+        end
+      end
+    end
+  end
+
   describe '#all_commit_shas' do
     context 'when merge request is persisted' do
       let(:all_commit_shas) do