Add specs for Package.sort_by_attribute

ee/spec/models/packages/package_spec.rb

@@ -13,6 +13,61 @@ RSpec.describe Packages::Package, type: :model do
     it { is_expected.to have_one(:maven_metadatum).inverse_of(:package) }
   end
 
+  describe '.sort_by_attribute' do
+    let_it_be(:group) { create(:group, :public) }
+    let_it_be(:project) { create(:project, :public, namespace: group, name: 'project A') }
+    let!(:package1) { create(:npm_package, project: project, version: '3.1.0', name: "@#{project.root_namespace.path}/foo1") }
+    let!(:package2) { create(:nuget_package, project: project, version: '2.0.4') }
+    let(:package3) { create(:maven_package, project: project, version: '1.1.1', name: 'zzz') }
+
+    before do
+      travel_to(1.day.ago) do
+        package3
+      end
+    end
+
+    RSpec.shared_examples 'package sorting by attribute' do |order_by|
+      subject { described_class.where(id: packages.map(&:id)).sort_by_attribute("#{order_by}_#{sort}").to_a }
+
+      context "sorting by #{order_by}" do
+        context 'ascending order' do
+          let(:sort) { 'asc' }
+
+          it { is_expected.to eq packages }
+        end
+
+        context 'descending order' do
+          let(:sort) { 'desc' }
+
+          it { is_expected.to eq packages.reverse }
+        end
+      end
+    end
+
+    it_behaves_like 'package sorting by attribute', 'name' do
+      let(:packages) { [package1, package2, package3] }
+    end
+
+    it_behaves_like 'package sorting by attribute', 'created_at' do
+      let(:packages) { [package3, package1, package2] }
+    end
+
+    it_behaves_like 'package sorting by attribute', 'version' do
+      let(:packages) { [package3, package2, package1] }
+    end
+
+    it_behaves_like 'package sorting by attribute', 'type' do
+      let(:packages) { [package3, package1, package2] }
+    end
+
+    it_behaves_like 'package sorting by attribute', 'project_path' do
+      let(:another_project) { create(:project, :public, namespace: group, name: 'project B') }
+      let!(:package4) { create(:npm_package, project: another_project, version: '3.1.0', name: "@#{project.root_namespace.path}/bar") }
+
+      let(:packages) { [package1, package2, package3, package4] }
+    end
+  end
+
   describe 'validations' do
     subject { create(:package) }