chore: Add code coverage to CustomRoyaltyFeeAssessor, CustomFixedFeeAssessor

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

@@ -100,21 +100,19 @@ public void assessRoyaltyFees(
                 final var fallbackFee = asFixedFee(
                         fallback.amount(), fallback.denominatingTokenId(), collector, fee.allCollectorsAreExempt());
                 fixedFeeAssessor.assessFixedFee(feeMeta, receiver, fallbackFee, result);
+                // We don't want to charge the fallback fee for each nft transfer, if the receiver has already
+                // paid it for this token, so track that royalty is paid once. Here, receiver pays fallback fees
+                result.addToRoyaltiesPaid(Pair.of(receiver, tokenId));
             } else {
                 if (!isPayerExempt(feeMeta, fee, sender)) {
                     chargeRoyalty(exchangedValue, fee, result);
+                    // We don't want to charge the fallback fee for each nft transfer, if the receiver has already
+                    // paid it for this token, so track that royalty is paid once. Here, Sender effectively pays percent
+                    // royalties
+                    result.addToRoyaltiesPaid(Pair.of(sender, tokenId));
                 }
             }
         }
-        // We don't want to charge the fallback fee for each nft transfer, if the receiver has already
-        // paid it for this token
-        if (exchangedValue.isEmpty()) {
-            // Receiver pays fallback fees
-            result.addToRoyaltiesPaid(Pair.of(receiver, tokenId));
-        } else {
-            // Sender effectively pays percent royalties
-            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

@@ -0,0 +1,122 @@
+/*
+ * Copyright (C) 2024 Hedera Hashgraph, LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.hedera.node.app.service.token.impl.test.handlers.transfer.customfees;
+
+import static com.hedera.node.app.service.token.impl.handlers.BaseCryptoHandler.asAccount;
+import static com.hedera.node.app.service.token.impl.handlers.BaseTokenHandler.asToken;
+import static com.hedera.node.app.service.token.impl.test.handlers.util.CryptoTokenHandlerTestBase.withFixedFee;
+import static com.hedera.node.app.service.token.impl.test.handlers.util.TransferUtil.asNftTransferList;
+import static org.assertj.core.api.Assertions.assertThat;
+
+import com.hedera.hapi.node.base.AccountID;
+import com.hedera.hapi.node.base.TokenID;
+import com.hedera.hapi.node.base.TokenTransferList;
+import com.hedera.hapi.node.base.TokenType;
+import com.hedera.hapi.node.transaction.AssessedCustomFee;
+import com.hedera.hapi.node.transaction.CustomFee;
+import com.hedera.hapi.node.transaction.FixedFee;
+import com.hedera.node.app.service.token.impl.handlers.transfer.customfees.AssessmentResult;
+import com.hedera.node.app.service.token.impl.handlers.transfer.customfees.CustomFeeMeta;
+import com.hedera.node.app.service.token.impl.handlers.transfer.customfees.CustomFixedFeeAssessor;
+import java.util.List;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+@ExtendWith(MockitoExtension.class)
+public class CustomFixedFeeAssessorTest {
+
+    private CustomFixedFeeAssessor subject;
+
+    private AssessmentResult result;
+
+    private final AccountID payer = asAccount(4001);
+    private final AccountID otherCollector = asAccount(1001);
+    private final AccountID funding = asAccount(98);
+    private final TokenID firstFungibleTokenId = asToken(3000);
+    private final AccountID minter = asAccount(6000);
+    private final TokenID nonFungibleTokenId = asToken(70000);
+    private final TokenTransferList nftTransferList = asNftTransferList(nonFungibleTokenId, payer, funding, 1);
+    final FixedFee htsFixedFee = FixedFee.newBuilder()
+            .denominatingTokenId(firstFungibleTokenId)
+            .amount(1)
+            .build();
+    final FixedFee hbarFixedFee = FixedFee.newBuilder().amount(1).build();
+    private final AssessedCustomFee htsAssessedFee = AssessedCustomFee.newBuilder()
+            .amount(1)
+            .tokenId(firstFungibleTokenId)
+            .effectivePayerAccountId(payer)
+            .feeCollectorAccountId(otherCollector)
+            .build();
+    private final AssessedCustomFee hbarAssessedFee = AssessedCustomFee.newBuilder()
+            .amount(1)
+            .effectivePayerAccountId(payer)
+            .feeCollectorAccountId(otherCollector)
+            .build();
+
+    @BeforeEach
+    void setUp() {
+        subject = new CustomFixedFeeAssessor();
+    }
+
+    @Test
+    void delegatesToHbarWhenDenomIsNull() {
+        result = new AssessmentResult(List.of(nftTransferList), List.of());
+        final var hbarFee = withFixedFee(hbarFixedFee, otherCollector);
+        final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
+
+        subject.assessFixedFees(feeMeta, payer, result);
+        assertThat(result.getAssessedCustomFees()).isNotEmpty();
+        assertThat(result.getAssessedCustomFees()).contains(hbarAssessedFee);
+    }
+
+    @Test
+    void delegatesToHtsWhenDenomIsNonNull() {
+        result = new AssessmentResult(List.of(nftTransferList), List.of());
+        final var hbarFee = withFixedFee(htsFixedFee, otherCollector);
+        final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
+
+        subject.assessFixedFees(feeMeta, payer, result);
+        assertThat(result.getAssessedCustomFees()).isNotEmpty();
+        assertThat(result.getAssessedCustomFees()).contains(htsAssessedFee);
+    }
+
+    @Test
+    void fixedCustomFeeExemptIsOk() {
+        result = new AssessmentResult(List.of(nftTransferList), List.of());
+        final var hbarFee = withFixedFee(htsFixedFee, payer);
+        final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
+
+        subject.assessFixedFees(feeMeta, payer, result);
+        assertThat(result.getAssessedCustomFees()).isEmpty();
+    }
+
+    @Test
+    void exemptsAssessmentWhenSenderSameAsCollector() {
+        result = new AssessmentResult(List.of(nftTransferList), List.of());
+        final var hbarFee = withFixedFee(htsFixedFee, payer);
+        final var feeMeta = withCustomFeeMeta(List.of(hbarFee), TokenType.FUNGIBLE_COMMON);
+
+        subject.assessFixedFees(feeMeta, payer, result);
+        assertThat(result.getAssessedCustomFees()).isEmpty();
+    }
+
+    private CustomFeeMeta withCustomFeeMeta(List<CustomFee> customFees, TokenType tokenType) {
+        return new CustomFeeMeta(firstFungibleTokenId, minter, customFees, tokenType);
+    }
+}