1 files changed, 71 insertions, 0 deletions
diff --git a/spec/requests/projects/issues_controller_spec.rb b/spec/requests/projects/issues_controller_spec.rb
new file mode 100644
index 00000000000..f44b1f4d502
--- /dev/null
+++ b/spec/requests/projects/issues_controller_spec.rb
@@ -0,0 +1,71 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Projects::IssuesController do
+  let_it_be(:issue) { create(:issue) }
+  let_it_be(:group) { create(:group) }
+  let_it_be(:project) { issue.project }
+  let_it_be(:user) { issue.author }
+
+  before do
+    login_as(user)
+  end
+
+  describe 'GET #discussions' do
+    let_it_be(:discussion) { create(:discussion_note_on_issue, noteable: issue, project: issue.project) }
+    let_it_be(:discussion_reply) { create(:discussion_note_on_issue, noteable: issue, project: issue.project, in_reply_to: discussion) }
+    let_it_be(:state_event) { create(:resource_state_event, issue: issue) }
+    let_it_be(:discussion_2) { create(:discussion_note_on_issue, noteable: issue, project: issue.project) }
+    let_it_be(:discussion_3) { create(:discussion_note_on_issue, noteable: issue, project: issue.project) }
+
+    context 'pagination' do
+      def get_discussions(**params)
+        get discussions_project_issue_path(project, issue, params: params.merge(format: :json))
+      end
+
+      it 'returns paginated notes and cursor based on per_page param' do
+        get_discussions(per_page: 2)
+
+        discussions = Gitlab::Json.parse(response.body)
+        notes = discussions.flat_map { |d| d['notes'] }
+
+        expect(discussions.count).to eq(2)
+        expect(notes).to match([
+          a_hash_including('id' => discussion.id.to_s),
+          a_hash_including('id' => discussion_reply.id.to_s),
+          a_hash_including('type' => 'StateNote')
+        ])
+
+        cursor = response.header['X-Next-Page-Cursor']
+        expect(cursor).to be_present
+
+        get_discussions(per_page: 1, cursor: cursor)
+
+        discussions = Gitlab::Json.parse(response.body)
+        notes = discussions.flat_map { |d| d['notes'] }
+
+        expect(discussions.count).to eq(1)
+        expect(notes).to match([
+          a_hash_including('id' => discussion_2.id.to_s)
+        ])
+      end
+
+      context 'when paginated_issue_discussions is disabled' do
+        before do
+          stub_feature_flags(paginated_issue_discussions: false)
+        end
+
+        it 'returns all discussions and ignores per_page param' do
+          get_discussions(per_page: 2)
+
+          discussions = Gitlab::Json.parse(response.body)
+          notes = discussions.flat_map { |d| d['notes'] }
+
+          expect(discussions.count).to eq(4)
+          expect(notes.count).to eq(5)
+        end
+      end
+    end
+  end
+end