Improve specs using subject

spec/models/service_spec.rb

@@ -104,22 +104,20 @@ describe Service do
 
   describe "Test Button" do
     describe '#can_test?' do
+      subject { service.can_test? }
+
       let(:service) { create(:service, project: project) }
 
       context 'when repository is not empty' do
         let(:project) { create(:project, :repository) }
 
-        it 'returns true' do
-          expect(service.can_test?).to be true
-        end
+        it { is_expected.to be true }
       end
 
       context 'when repository is empty' do
         let(:project) { create(:project) }
 
-        it 'returns true' do
-          expect(service.can_test?).to be true
-        end
+        it { is_expected.to be true }
       end
 
       context 'when instance-level service' do
@@ -128,9 +126,7 @@ describe Service do
             service_type.constantize.new(instance: true)
           end
 
-          it 'returns false' do
-            expect(service.can_test?).to be_falsey
-          end
+          it { is_expected.to be_falsey }
         end
       end
     end