move dfp_ad_unit_code to imp.ext (prebid#7637)

modules/ixBidAdapter.js

@@ -646,7 +646,7 @@ function buildRequest(validBidRequests, bidderRequest, impressions, version) {
     }
 
     if (impressionObjects.length && BANNER in impressionObjects[0]) {
-      const { id, banner: { topframe } } = impressionObjects[0];
+      const { id, banner: { topframe }, ext } = impressionObjects[0];
       const _bannerImpression = {
         id,
         banner: {
@@ -655,6 +655,12 @@ function buildRequest(validBidRequests, bidderRequest, impressions, version) {
         },
       }
 
+      if (ext.dfp_ad_unit_code) {
+        _bannerImpression.ext = {
+          dfp_ad_unit_code: ext.dfp_ad_unit_code
+        }
+      }
+
       if ('bidfloor' in impressionObjects[0]) {
         _bannerImpression.bidfloor = impressionObjects[0].bidfloor;
       }

test/spec/modules/ixBidAdapter_spec.js

@@ -1405,16 +1405,16 @@ describe('IndexexchangeAdapter', function () {
         }
       };
       const requests = spec.buildRequests(validBids, DEFAULT_OPTION);
-      const { dfp_ad_unit_code } = JSON.parse(requests[0].data.r).imp[0].banner.format[0].ext;
+      const { ext: { dfp_ad_unit_code } } = JSON.parse(requests[0].data.r).imp[0];
       expect(dfp_ad_unit_code).to.equal(AD_UNIT_CODE);
     });
 
     it('should not send dfp_adunit_code in request if ortb2Imp.ext.data.adserver.adslot does not exists', function () {
       const validBids = utils.deepClone(DEFAULT_BANNER_VALID_BID);
       const requests = spec.buildRequests(validBids, DEFAULT_OPTION);
-      const { dfp_ad_unit_code } = JSON.parse(requests[0].data.r).imp[0].banner.format[0].ext;
+      const { ext } = JSON.parse(requests[0].data.r).imp[0];
 
-      expect(dfp_ad_unit_code).to.not.exist;
+      expect(ext).to.not.exist;
     });
 
     it('payload should have correct format and value', function () {