Test: Fix default value of targeting.hb_pb (#4191)

Author: osulzhenko

src/test/groovy/org/prebid/server/functional/tests/TargetingSpec.groovy

@@ -62,6 +62,7 @@ class TargetingSpec extends BaseSpec {
     private static final String HB_ENV_AMP = "amp"
     private static final Integer MAIN_RANK = 1
     private static final Integer SUBORDINATE_RANK = 2
+    private static final String EMPTY_CPM = "0.0"
 
     def "PBS should include targeting bidder specific keys when alwaysIncludeDeals is true and deal bid wins"() {
         given: "Bid request with alwaysIncludeDeals = true"
@@ -543,6 +544,30 @@ class TargetingSpec extends BaseSpec {
         assert targetingKeyMap["hb_pb"] == String.format("%,.2f", max.setScale(precision, RoundingMode.DOWN))
     }
 
+    def "PBS auction shouldn't delete bid and update targeting if price equal zero and dealId present"() {
+        given: "Default bid request with stored response"
+        def bidRequest = BidRequest.defaultBidRequest.tap {
+            ext.prebid.targeting = Targeting.createWithAllValuesSetTo(true)
+        }
+
+        and: "Bid response with zero price"
+        def bidResponse = BidResponse.getDefaultBidResponse(bidRequest).tap {
+            seatbid[0].bid[0].price = 0
+            seatbid[0].bid[0].dealid = PBSUtils.randomString
+        }
+
+        and: "Set bidder response"
+        bidder.setResponse(bidRequest.id, bidResponse)
+
+        when: "PBS processes auction request"
+        def response = defaultPbsService.sendAuctionRequest(bidRequest)
+
+        then: "Response should contain proper targeting hb_pb"
+        def targetingKeyMap = response.seatbid?.first()?.bid?.first()?.ext?.prebid?.targeting
+        assert targetingKeyMap["hb_pb"] == EMPTY_CPM
+        assert targetingKeyMap["hb_pb_generic"] == EMPTY_CPM
+    }
+
     def "PBS auction should use default targeting prefix when ext.prebid.targeting.prefix is biggest that twenty"() {
         given: "Bid request with long targeting prefix"
         def prefix = PBSUtils.getRandomString(30)