Create with_plan namespace scope

app/models/ee/namespace.rb

@@ -21,6 +21,8 @@ module EE
     prepended do
       has_one :namespace_statistics, dependent: :destroy
 
+      scope :with_plan, -> { where.not(plan: [nil, '']) }
+
       delegate :shared_runners_minutes, :shared_runners_seconds, :shared_runners_seconds_last_reset,
         to: :namespace_statistics, allow_nil: true
 
@@ -58,7 +60,7 @@ module EE
     def plans
       @ancestors_plans ||=
         if parent_id
-          ancestors.where.not(plan: [nil, '']).reorder(nil).pluck('DISTINCT plan') + [plan]
+          ancestors.with_plan.reorder(nil).pluck('DISTINCT plan') + [plan]
         else
           [plan]
         end

spec/models/ee/namespace_spec.rb

@@ -10,6 +10,38 @@ describe Namespace, models: true do
   it { is_expected.to delegate_method(:shared_runners_seconds_last_reset).to(:namespace_statistics) }
   it { is_expected.to validate_inclusion_of(:plan).in_array(Namespace::EE_PLANS.keys).allow_blank }
 
+  context 'scopes' do
+    describe '.with_plan' do
+      let!(:namespace) { create :namespace, plan: namespace_plan }
+
+      context 'plan is set' do
+        let(:namespace_plan) { EE::Namespace::BRONZE_PLAN }
+
+        it 'returns namespaces with plan' do
+          expect(described_class.with_plan).to eq([namespace])
+        end
+      end
+
+      context 'plan is not set' do
+        context 'plan is empty string' do
+          let(:namespace_plan) { '' }
+
+          it 'returns no namespace' do
+            expect(described_class.with_plan).to be_empty
+          end
+        end
+
+        context 'plan is nil' do
+          let(:namespace_plan) { nil }
+
+          it 'returns no namespace' do
+            expect(described_class.with_plan).to be_empty
+          end
+        end
+      end
+    end
+  end
+
   describe '#feature_available?' do
     let(:group) { create(:group, plan: plan_license) }