Fix for Issue 3130: passing new copy of adUnits object to every adapter (prebid#3131)

* passing new copy of adUnits object to every adapter

* add test to verify bidders can't mutate eachothers bid requests

Author: pm-harshad-mane

src/adaptermanager.js

@@ -194,7 +194,7 @@ exports.makeBidRequests = function(adUnits, auctionStart, auctionId, cbTimeout,
         auctionId,
         bidderRequestId,
         tid,
-        bids: getBids({bidderCode, auctionId, bidderRequestId, 'adUnits': adUnitsS2SCopy, labels}),
+        bids: getBids({bidderCode, auctionId, bidderRequestId, 'adUnits': utils.deepClone(adUnitsS2SCopy), labels}),
         auctionStart: auctionStart,
         timeout: _s2sConfig.timeout,
         src: CONSTANTS.S2S.SRC,
@@ -229,7 +229,7 @@ exports.makeBidRequests = function(adUnits, auctionStart, auctionId, cbTimeout,
       bidderCode,
       auctionId,
       bidderRequestId,
-      bids: getBids({bidderCode, auctionId, bidderRequestId, 'adUnits': adUnitsClientCopy, labels}),
+      bids: getBids({bidderCode, auctionId, bidderRequestId, 'adUnits': utils.deepClone(adUnitsClientCopy), labels}),
       auctionStart: auctionStart,
       timeout: cbTimeout,
       refererInfo

test/spec/unit/core/adapterManager_spec.js

@@ -762,6 +762,26 @@ describe('adapterManager tests', function () {
       })
     });
 
+    it('should make separate bidder request objects for each bidder', () => {
+      adUnits = [utils.deepClone(getAdUnits()[0])];
+
+      let bidRequests = AdapterManager.makeBidRequests(
+        adUnits,
+        Date.now(),
+        utils.getUniqueIdentifierStr(),
+        function callback() {},
+        []
+      );
+
+      let sizes1 = bidRequests[1].bids[0].sizes;
+      let sizes2 = bidRequests[0].bids[0].sizes;
+
+      // mutate array
+      sizes1.splice(0, 1);
+
+      expect(sizes1).not.to.deep.equal(sizes2);
+    });
+
     describe('setBidderSequence', function () {
       beforeEach(function () {
         sinon.spy(utils, 'shuffle');