Let tie breaker order follow global sort direction

Related issue: https://gitlab.com/gitlab-org/gitlab/issues/195881

changelogs/unreleased/ab-tie-breaker-order.yml

+---
+title: Let tie breaker order follow primary sort direction (API)
+merge_request: 22795
+author:
+type: changed

lib/api/helpers.rb

@@ -316,7 +316,7 @@ module API
 
     def order_options_with_tie_breaker
       order_options = { params[:order_by] => params[:sort] }
-      order_options['id'] ||= 'desc'
+      order_options['id'] ||= params[:sort] || 'asc'
       order_options
     end
 

spec/lib/api/helpers_spec.rb

@@ -188,4 +188,46 @@ describe API::Helpers do
       subject.track_event('my_event', category: nil)
     end
   end
+
+  describe '#order_options_with_tie_breaker' do
+    let(:subject) { Class.new.include(described_class).new.order_options_with_tie_breaker }
+
+    before do
+      allow_any_instance_of(described_class).to receive(:params).and_return(params)
+    end
+
+    context 'with non-id order given' do
+      context 'with ascending order' do
+        let(:params) { { order_by: 'name', sort: 'asc' } }
+
+        it 'adds id based ordering with same direction as primary order' do
+          expect(subject).to eq({ 'name' => 'asc', 'id' => 'asc' })
+        end
+      end
+
+      context 'with descending order' do
+        let(:params) { { order_by: 'name', sort: 'desc' } }
+
+        it 'adds id based ordering with same direction as primary order' do
+          expect(subject).to eq({ 'name' => 'desc', 'id' => 'desc' })
+        end
+      end
+    end
+
+    context 'with non-id order but no direction given' do
+      let(:params) { { order_by: 'name' } }
+
+      it 'adds ID ASC order' do
+        expect(subject).to eq({ 'name' => nil, 'id' => 'asc' })
+      end
+    end
+
+    context 'with id order given' do
+      let(:params) { { order_by: 'id', sort: 'asc' } }
+
+      it 'does not add an additional order' do
+        expect(subject).to eq({ 'id' => 'asc' })
+      end
+    end
+  end
 end