Add test for when course.enrichments are not loaded

app/models/required_qualifications_summary.rb

@@ -8,7 +8,6 @@ def initialize(course)
   end
 
   def extract
-    # This performance improvement saves ~100 database queries in the courses api endpoint
     legacy_qualifications_attribute = if course.enrichments.loaded?
                                         course.enrichments.max_by(&:created_at)&.required_qualifications
                                       else

spec/models/required_qualifications_summary_spec.rb

@@ -14,6 +14,18 @@
       end
     end
 
+    context 'when the course enrichments are not loaded' do
+      let(:enrichment) { build(:course_enrichment, :published, required_qualifications: 'GCSE Computer Science') }
+      let(:course) { create(:course, enrichments: [enrichment]) }
+
+      it 'returns the expected value' do
+        course.reload
+        expect(course.enrichments.loaded?).to be_falsey
+        summary = described_class.new(course).extract
+        expect(summary).to eq 'GCSE Computer Science'
+      end
+    end
+
     context 'when required_qualifications enrichment attribute is blank' do
       it 'assembles a whole summary based on course attributes' do
         course = create(:course, :primary)