Fix for not syncing bidders. (#1598)

* fix for #1582

* fixed typo and add unit tests

modules/prebidServerBidAdapter.js

@@ -215,10 +215,11 @@ function PrebidServer() {
    */
   baseAdapter.queueSync = function({bidderCodes}) {
     let syncedList = StorageManager.get(pbjsSyncsKey) || [];
-    if (_cookiesQueued || syncedList.length === bidderCodes.length) {
+    // filter synced bidders - https://github.com/prebid/Prebid.js/issues/1582
+    syncedList = bidderCodes.filter(bidder => !syncedList.includes(bidder));
+    if (syncedList.length === 0) {
       return;
     }
-    _cookiesQueued = true;
     const payload = JSON.stringify({
       uuid: utils.generateUUID(),
       bidders: bidderCodes

test/spec/modules/prebidServerBidAdapter_spec.js

@@ -5,6 +5,7 @@ import CONSTANTS from 'src/constants.json';
 import * as utils from 'src/utils';
 import cookie from 'src/cookie';
 import { userSync } from 'src/userSync';
+import { StorageManager } from 'src/storagemanager';
 
 let CONFIG = {
   accountId: '1',
@@ -157,6 +158,37 @@ describe('S2S Adapter', () => {
 
   beforeEach(() => adapter = new Adapter());
 
+  describe('queue sync function', () => {
+    let server;
+    let storageManagerAddStub;
+
+    beforeEach(() => {
+      server = sinon.fakeServer.create();
+      storageManagerAddStub = sinon.stub(StorageManager, 'add');
+    });
+
+    afterEach(() => {
+      server.restore();
+      storageManagerAddStub.restore();
+      localStorage.removeItem('pbjsSyncs');
+    });
+
+    it('exists and is a function', () => {
+      expect(adapter.queueSync).to.exist.and.to.be.a('function');
+    });
+
+    it('requests only bidders that are not already synced', () => {
+      server.respondWith(JSON.stringify({status: 'ok', bidderCodes: ['rubicon'] }));
+      const reqBidderCodes = ['appnexus', 'newBidder'];
+      const syncedBidders = ['appnexus', 'rubicon'];
+      localStorage.setItem('pbjsSyncs', JSON.stringify(syncedBidders));
+      adapter.setConfig(CONFIG);
+      adapter.queueSync({bidderCodes: reqBidderCodes});
+      server.respond();
+      sinon.assert.calledTwice(storageManagerAddStub);
+    });
+  });
+
   describe('request function', () => {
     let xhr;
     let requests;