convert buyQuest (gold) to the purchase refactoring / check quantity to be a number (#10244)

test/common/ops/buy/buyQuest.js

@@ -1,7 +1,7 @@
 import {
   generateUser,
 } from '../../../helpers/common.helper';
-import buyQuest from '../../../../website/common/script/ops/buy/buyQuest';
+import {BuyQuestWithGoldOperation} from '../../../../website/common/script/ops/buy/buyQuest';
 import {
   BadRequest,
   NotAuthorized,
@@ -13,6 +13,12 @@ describe('shared.ops.buyQuest', () => {
   let user;
   let analytics = {track () {}};
 
+  function buyQuest (_user, _req, _analytics) {
+    const buyOp = new BuyQuestWithGoldOperation(_user, _req, _analytics);
+
+    return buyOp.purchase();
+  }
+
   beforeEach(() => {
     user = generateUser();
     sinon.stub(analytics, 'track');