diff --git a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/processor/TransactionTracerTest.java b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/processor/TransactionTracerTest.java
index 1215a898c1b..d800baa94fd 100644
--- a/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/processor/TransactionTracerTest.java
+++ b/ethereum/api/src/test/java/org/hyperledger/besu/ethereum/api/jsonrpc/internal/processor/TransactionTracerTest.java
@@ -118,6 +118,7 @@ public void setUp() throws Exception {
     when(protocolSpec.getMiningBeneficiaryCalculator()).thenReturn(BlockHeader::getCoinbase);
     when(blockchain.getChainHeadHeader()).thenReturn(blockHeader);
     when(protocolSpec.getBadBlocksManager()).thenReturn(new BadBlockManager());
+    when(mutableWorldState.copy()).thenReturn(mutableWorldState);
   }
 
   @Test