1 files changed, 43 insertions, 0 deletions
diff --git a/spec/lib/atlassian/jira_connect/serializers/pull_request_entity_spec.rb b/spec/lib/atlassian/jira_connect/serializers/pull_request_entity_spec.rb
new file mode 100644
index 00000000000..872ba1ab43d
--- /dev/null
+++ b/spec/lib/atlassian/jira_connect/serializers/pull_request_entity_spec.rb
@@ -0,0 +1,43 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Atlassian::JiraConnect::Serializers::PullRequestEntity do
+  let_it_be(:project) { create_default(:project, :repository) }
+  let_it_be(:merge_requests) { create_list(:merge_request, 2, :unique_branches) }
+  let_it_be(:notes) { create_list(:note, 2, system: false, noteable: merge_requests.first) }
+
+  subject { described_class.represent(merge_requests).as_json }
+
+  it 'exposes commentCount' do
+    expect(subject.first[:commentCount]).to eq(2)
+  end
+
+  context 'with user_notes_count option' do
+    let(:user_notes_count) { merge_requests.map { |merge_request| [merge_request.id, 1] }.to_h }
+
+    subject { described_class.represent(merge_requests, user_notes_count: user_notes_count).as_json }
+
+    it 'avoids N+1 database queries' do
+      control_count = ActiveRecord::QueryRecorder.new do
+        described_class.represent(merge_requests, user_notes_count: user_notes_count)
+      end.count
+
+      merge_requests << create(:merge_request, :unique_branches)
+
+      expect { subject }.not_to exceed_query_limit(control_count)
+    end
+
+    it 'uses counts from user_notes_count' do
+      expect(subject.map { |entity| entity[:commentCount] }).to match_array([1, 1, 1])
+    end
+
+    context 'when count is missing for some MRs' do
+      let(:user_notes_count) { [[merge_requests.last.id, 1]].to_h }
+
+      it 'uses 0 as default when count for the MR is not available' do
+        expect(subject.map { |entity| entity[:commentCount] }).to match_array([0, 0, 1])
+      end
+    end
+  end
+end