Add coverage for misc serializers (#32781)

spec/serializers/rest/extended_description_serializer_spec.rb

@@ -0,0 +1,35 @@
+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe REST::ExtendedDescriptionSerializer do
+  subject { serialized_record_json(record, described_class) }
+
+  describe 'serialization' do
+    context 'with text present' do
+      let(:record) { ExtendedDescription.new text: 'Hello world', updated_at: Date.new(2024, 1, 1) }
+
+      it 'returns expected values' do
+        expect(subject)
+          .to include(
+            'content' => eq(<<~HTML),
+              <p>Hello world</p>
+            HTML
+            'updated_at' => eq('2024-01-01')
+          )
+      end
+    end
+
+    context 'with text missing' do
+      let(:record) { ExtendedDescription.new text: nil, updated_at: Date.new(2024, 1, 1) }
+
+      it 'returns expected values' do
+        expect(subject)
+          .to include(
+            'content' => eq(''),
+            'updated_at' => eq('2024-01-01')
+          )
+      end
+    end
+  end
+end