1 files changed, 52 insertions, 0 deletions
diff --git a/spec/requests/projects/merge_requests_discussions_spec.rb b/spec/requests/projects/merge_requests_discussions_spec.rb
new file mode 100644
index 00000000000..5945561aa7b
--- /dev/null
+++ b/spec/requests/projects/merge_requests_discussions_spec.rb
@@ -0,0 +1,52 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe 'merge requests discussions' do
+  # Further tests can be found at merge_requests_controller_spec.rb
+  describe 'GET /:namespace/:project/merge_requests/:iid/discussions' do
+    let(:project) { create(:project, :repository) }
+    let(:user) { project.owner }
+    let(:merge_request) { create(:merge_request_with_diffs, target_project: project, source_project: project) }
+
+    before do
+      project.add_developer(user)
+      login_as(user)
+    end
+
+    def send_request
+      get discussions_namespace_project_merge_request_path(namespace_id: project.namespace, project_id: project, id: merge_request.iid)
+    end
+
+    it 'returns 200' do
+      send_request
+
+      expect(response.status).to eq(200)
+    end
+
+    # https://docs.gitlab.com/ee/development/query_recorder.html#use-request-specs-instead-of-controller-specs
+    it 'avoids N+1 DB queries', :request_store do
+      control = ActiveRecord::QueryRecorder.new { send_request }
+
+      create(:diff_note_on_merge_request, noteable: merge_request,
+             project: merge_request.project)
+
+      expect do
+        send_request
+      end.not_to exceed_query_limit(control)
+    end
+
+    it 'limits Gitaly queries', :request_store do
+      Gitlab::GitalyClient.allow_n_plus_1_calls do
+        create_list(:diff_note_on_merge_request, 7, noteable: merge_request,
+                    project: merge_request.project)
+      end
+
+      # The creations above write into the Gitaly counts
+      Gitlab::GitalyClient.reset_counts
+
+      expect { send_request }
+        .to change { Gitlab::GitalyClient.get_request_count }.by_at_most(4)
+    end
+  end
+end