1 files changed, 53 insertions, 0 deletions
diff --git a/spec/requests/projects/pipelines_controller_spec.rb b/spec/requests/projects/pipelines_controller_spec.rb
index 7bdb66755db..aa3fefdef14 100644
--- a/spec/requests/projects/pipelines_controller_spec.rb
+++ b/spec/requests/projects/pipelines_controller_spec.rb
@@ -75,6 +75,59 @@ RSpec.describe Projects::PipelinesController, feature_category: :continuous_inte
       expect(response).to have_gitlab_http_status(:ok)
     end
 
+    context 'when pipeline_stage_set_last_modified is disabled' do
+      before do
+        stub_feature_flags(pipeline_stage_set_last_modified: false)
+      end
+
+      it 'does not set Last-Modified' do
+        create(:ci_build, :retried, :failed, pipeline: pipeline, stage: 'build')
+
+        request_build_stage
+
+        expect(response).to have_gitlab_http_status(:ok)
+        expect(response.headers['Last-Modified']).to be_nil
+        expect(response.headers['Cache-Control']).to eq('max-age=0, private, must-revalidate')
+      end
+    end
+
+    context 'when pipeline_stage_set_last_modified is enabled' do
+      before do
+        stub_feature_flags(pipeline_stage_set_last_modified: true)
+        stage.statuses.update_all(updated_at: status_timestamp)
+      end
+
+      let(:last_modified) { DateTime.parse(response.headers['Last-Modified']).utc }
+      let(:cache_control) { response.headers['Cache-Control'] }
+      let(:expected_cache_control) { 'max-age=0, private, must-revalidate' }
+
+      context 'when status.updated_at is before stage.updated' do
+        let(:stage) { pipeline.stage('build') }
+        let(:status_timestamp) { stage.updated_at - 10.minutes }
+
+        it 'sets correct Last-Modified of stage.updated_at' do
+          request_build_stage
+
+          expect(response).to have_gitlab_http_status(:ok)
+          expect(last_modified).to be_within(1.second).of stage.updated_at
+          expect(cache_control).to eq(expected_cache_control)
+        end
+      end
+
+      context 'when status.updated_at is after stage.updated' do
+        let(:stage) { pipeline.stage('build') }
+        let(:status_timestamp) { stage.updated_at + 10.minutes }
+
+        it 'sets correct Last-Modified of max(status.updated_at)' do
+          request_build_stage
+
+          expect(response).to have_gitlab_http_status(:ok)
+          expect(last_modified).to be_within(1.second).of status_timestamp
+          expect(cache_control).to eq(expected_cache_control)
+        end
+      end
+    end
+
     context 'with retried builds' do
       it 'does not execute N+1 queries' do
         create(:ci_build, :retried, :failed, pipeline: pipeline, stage: 'build')