Add test for positive quantity

ee/app/assets/javascripts/subscriptions/buy_minutes/components/order_summary/summary_details.vue

@@ -65,7 +65,7 @@ export default {
     <div class="d-flex justify-content-between bold gl-mt-3 gl-mb-3">
       <div data-testid="selected-plan">
         {{ sprintf($options.i18n.selectedPlanText, { selectedPlanText }) }}
-        <span v-if="quantity > 0" data-testid="quantity">{{
+        <span v-if="quantity" data-testid="quantity">{{
           sprintf($options.i18n.quantity, { quantity })
         }}</span>
       </div>

ee/spec/frontend/subscriptions/buy_minutes/components/order_summary_spec.js

@@ -76,6 +76,10 @@ describe('Order Summary', () => {
         subscription: { quantity: 3 },
       });
     });
+
+    it('renders amount', () => {
+      expect(wrapper.find('[data-testid="amount"]').text()).toBe('$30');
+    });
   });
 
   describe('when quantity is less than or equal to zero', () => {