fixing SRA p_pos (prebid#4337)

modules/rubiconBidAdapter.js

@@ -410,9 +410,8 @@ export const spec = {
  };
 
  // add p_pos only if specified and valid
- if (params.position === 'atf' || params.position === 'btf') {
- data['p_pos'] = params.position;
- }
+ // For SRA we need to explicitly put empty semi colons so AE treats it as empty, instead of copying the latter value
+ data['p_pos'] = (params.position === 'atf' || params.position === 'btf') ? params.position : '';
 
  if ((bidRequest.userId || {}).tdid) {
  data['tpid_tdid'] = bidRequest.userId.tdid;

test/spec/modules/rubiconBidAdapter_spec.js

@@ -375,6 +375,42 @@ describe('the rubicon adapter', function () {
  expect(data['p_pos']).to.equal(undefined);
  });
 
+ it('should correctly send p_pos in sra fashion', function() {
+ sandbox.stub(config, 'getConfig').callsFake((key) => {
+ const config = {
+ 'rubicon.singleRequest': true
+ };
+ return config[key];
+ });
+ // first one is atf
+ var sraPosRequest = utils.deepClone(bidderRequest);
+
+ // second is not present
+ const bidCopy = utils.deepClone(sraPosRequest.bids[0]);
+ delete bidCopy.params.position;
+ sraPosRequest.bids.push(bidCopy);
+
+ // third is btf
+ const bidCopy1 = utils.deepClone(sraPosRequest.bids[0]);
+ bidCopy1.params.position = 'btf';
+ sraPosRequest.bids.push(bidCopy1);
+
+ // fourth is invalid (aka not atf or btf)
+ const bidCopy2 = utils.deepClone(sraPosRequest.bids[0]);
+ bidCopy2.params.position = 'unknown';
+ sraPosRequest.bids.push(bidCopy2);
+
+ // fifth is not present
+ const bidCopy3 = utils.deepClone(sraPosRequest.bids[0]);
+ delete bidCopy3.params.position;
+ sraPosRequest.bids.push(bidCopy3);
+
+ let [request] = spec.buildRequests(sraPosRequest.bids, sraPosRequest);
+ let data = parseQuery(request.data);
+
+ expect(data['p_pos']).to.equal('atf;;btf;;');
+ });
+
  it('ad engine query params should be ordered correctly', function () {
  sandbox.stub(Math, 'random').callsFake(() => 0.1);
  let [request] = spec.buildRequests(bidderRequest.bids, bidderRequest);