chore: Add code coverage for CustomFractionalFeeAssessor (#13278)

Signed-off-by: Neeharika-Sompalli <[email protected]>
Signed-off-by: Bilyana Gospodinova <[email protected]>

hedera-node/hedera-token-service-impl/src/main/java/com/hedera/node/app/service/token/impl/handlers/transfer/customfees/CustomFractionalFeeAssessor.java

@@ -200,7 +200,7 @@ private Map<AccountID, Long> filteredByExemptions(
      * @param fractionalFee the fractional fee
      * @return the amount owned to be paid as fractional custom fee
      */
-    private long amountOwed(final long givenUnits, @NonNull final FractionalFee fractionalFee) {
+    public long amountOwed(final long givenUnits, @NonNull final FractionalFee fractionalFee) {
         final var numerator = fractionalFee.fractionalAmountOrThrow().numerator();
         final var denominator = fractionalFee.fractionalAmountOrThrow().denominator();
         var nominalFee = 0L;

hedera-node/hedera-token-service-impl/src/main/java/com/hedera/node/app/service/token/impl/handlers/transfer/customfees/CustomRoyaltyFeeAssessor.java

@@ -106,14 +106,19 @@ public void assessRoyaltyFees(
                 }
             }
         }
+        // We check this outside the for loop above because a sender should only be marked as paid royalty, after
+        // assessing
+        // all the fees for the given token. If a sender is sending multiple NFTs of the same token, royalty fee
+        // should be paid only once.
         // We don't want to charge the fallback fee for each nft transfer, if the receiver has already
-        // paid it for this token. This should be added only once per token transfer, so this is
-        // added here.
+        // paid it for this token.
+
         if (exchangedValue.isEmpty()) {
             // Receiver pays fallback fees
             result.addToRoyaltiesPaid(Pair.of(receiver, tokenId));
         } else {
-            // Sender effectively pays percent royalties
+            // Sender effectively pays percent royalties. Here we don't check isPayerExempt because
+            // the sender could be exempt for one fee on token, but not other fees(if any) on the same token.
             result.addToRoyaltiesPaid(Pair.of(sender, tokenId));
         }
     }

hedera-node/hedera-token-service-impl/src/test/java/com/hedera/node/app/service/token/impl/test/handlers/transfer/customfees/CustomFixedFeeAssessorTest.java

@@ -77,7 +77,7 @@ void setUp() {
     @Test
     void delegatesToHbarWhenDenomIsNull() {
         result = new AssessmentResult(List.of(nftTransferList), List.of());
-        final var hbarFee = withFixedFee(hbarFixedFee, otherCollector);
+        final var hbarFee = withFixedFee(hbarFixedFee, otherCollector, false);
         final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
 
         subject.assessFixedFees(feeMeta, payer, result);
@@ -88,7 +88,7 @@ void delegatesToHbarWhenDenomIsNull() {
     @Test
     void delegatesToHtsWhenDenomIsNonNull() {
         result = new AssessmentResult(List.of(nftTransferList), List.of());
-        final var hbarFee = withFixedFee(htsFixedFee, otherCollector);
+        final var hbarFee = withFixedFee(htsFixedFee, otherCollector, false);
         final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
 
         subject.assessFixedFees(feeMeta, payer, result);
@@ -99,7 +99,7 @@ void delegatesToHtsWhenDenomIsNonNull() {
     @Test
     void fixedCustomFeeExemptIsOk() {
         result = new AssessmentResult(List.of(nftTransferList), List.of());
-        final var hbarFee = withFixedFee(htsFixedFee, payer);
+        final var hbarFee = withFixedFee(htsFixedFee, payer, false);
         final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
 
         subject.assessFixedFees(feeMeta, payer, result);
@@ -109,7 +109,7 @@ void fixedCustomFeeExemptIsOk() {
     @Test
     void exemptsAssessmentWhenSenderSameAsCollector() {
         result = new AssessmentResult(List.of(nftTransferList), List.of());
-        final var hbarFee = withFixedFee(htsFixedFee, payer);
+        final var hbarFee = withFixedFee(htsFixedFee, payer, false);
         final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
 
         subject.assessFixedFees(feeMeta, payer, result);
@@ -119,7 +119,7 @@ void exemptsAssessmentWhenSenderSameAsCollector() {
     @Test
     void ignoresIfPayerExempt() {
         result = new AssessmentResult(List.of(nftTransferList), List.of());
-        final var hbarFee = withFixedFee(htsFixedFee, payer);
+        final var hbarFee = withFixedFee(htsFixedFee, payer, false);
         final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
 
         subject.assessFixedFee(feeMeta, payer, hbarFee, result);