fix: test cases for parseWithdrawPsbt

TICKET: BTC-2545

Author: parvbitgo067

modules/abstract-lightning/src/lightning/parseWithdrawPsbt.ts

@@ -110,10 +110,15 @@ export function verifyChangeAddress(
       }).address;
       break;
     case 86: // P2TR (Taproot)
-      derivedAddress = utxolib.payments.p2tr({
-        pubkey: derivedPubkey,
-        network,
-      }).address;
+      // P2TR requires x-only pubkey (32 bytes)
+      const xOnlyPubkey = derivedPubkey.length === 33 ? derivedPubkey.subarray(1, 33) : derivedPubkey;
+      derivedAddress = utxolib.payments.p2tr(
+        {
+          pubkey: xOnlyPubkey,
+          network,
+        },
+        { eccLib: utxolib.ecc }
+      ).address;
       break;
     default:
       throw new Error(`Unsupported purpose: ${purpose}`);

modules/abstract-lightning/test/unit/lightning/createPsbt.ts

@@ -0,0 +1,175 @@
+import * as utxolib from '@bitgo/utxo-lib';
+
+export interface PsbtCreationOptions {
+  network: utxolib.Network;
+  inputValue?: number;
+  outputValue?: number;
+  outputAddress?: string;
+  changeValue?: number;
+  changeDerivationPath?: string;
+  changePurpose?: 49 | 84 | 86;
+  includeChangeOutput?: boolean;
+  masterKey?: utxolib.BIP32Interface; // Optional master key for deriving addresses
+}
+
+export interface PsbtCreationResult {
+  psbt: utxolib.Psbt;
+  masterKey: utxolib.BIP32Interface;
+  changeDerivationPath: string;
+  changePurpose: number;
+}
+
+/**
+ * Creates a PSBT for testing purposes with customizable options.
+ * This helper function generates a PSBT with a fake input and configurable outputs.
+ *
+ * @param options - Configuration options for PSBT creation
+ * @returns A constructed PSBT instance and the master key used
+ */
+export function createTestPsbt(options: PsbtCreationOptions): PsbtCreationResult {
+  const {
+    network,
+    inputValue = 500000,
+    outputValue = 100000,
+    outputAddress,
+    changeValue,
+    changeDerivationPath = "m/84'/0'/0'/1/6",
+    changePurpose = 84,
+    includeChangeOutput = true,
+    masterKey,
+  } = options;
+  const fixedSeed = Buffer.from('0101010101010101010101010101010101010101010101010101010101010101', 'hex');
+  const accountMasterKey = masterKey || utxolib.bip32.fromSeed(fixedSeed, network);
+
+  const inputPrivateKey = Buffer.from('0202020202020202020202020202020202020202020202020202020202020202', 'hex');
+  const inputKeyPair = utxolib.ECPair.fromPrivateKey(inputPrivateKey, { network });
+  const p2wpkhInput = utxolib.payments.p2wpkh({
+    pubkey: Buffer.from(inputKeyPair.publicKey),
+    network,
+  });
+
+  // Create a new PSBT instance
+  const psbt = new utxolib.Psbt({ network });
+
+  // Add a fake input to the PSBT
+  const fakeTxId = 'ca6852598b48230ac870814b935b0d982d3968eb00a1d97332dceb6cd9b8505e';
+  const fakeVout = 1;
+
+  psbt.addInput({
+    hash: fakeTxId,
+    index: fakeVout,
+    witnessUtxo: {
+      script: p2wpkhInput.output!,
+      value: BigInt(inputValue),
+    },
+    bip32Derivation: [
+      {
+        masterFingerprint: Buffer.alloc(4, 0),
+        path: "m/84'/0'/0'/0/0",
+        pubkey: Buffer.from(inputKeyPair.publicKey),
+      },
+    ],
+  });
+
+  // Add recipient output
+  let recipientAddress: string;
+  if (outputAddress) {
+    recipientAddress = outputAddress;
+  } else {
+    const recipientPrivateKey = Buffer.from('0303030303030303030303030303030303030303030303030303030303030303', 'hex');
+    const recipientKeyPair = utxolib.ECPair.fromPrivateKey(recipientPrivateKey, { network });
+    // P2TR requires x-only pubkey (32 bytes, without the prefix byte)
+    const xOnlyPubkey =
+      recipientKeyPair.publicKey.length === 33
+        ? recipientKeyPair.publicKey.subarray(1, 33)
+        : recipientKeyPair.publicKey;
+    const recipientP2tr = utxolib.payments.p2tr(
+      {
+        pubkey: xOnlyPubkey,
+        network,
+      },
+      { eccLib: utxolib.ecc }
+    );
+    recipientAddress = recipientP2tr.address!;
+  }
+
+  psbt.addOutput({
+    address: recipientAddress,
+    value: BigInt(outputValue),
+  });
+
+  // Add change output if requested
+  if (includeChangeOutput) {
+    const calculatedChangeValue = changeValue !== undefined ? changeValue : inputValue - outputValue - 10000; // 10k sats fee
+
+    // Parse the derivation path to get the change and address indices
+    // Expected format: m/purpose'/coin_type'/account'/change/address_index
+    const pathSegments = changeDerivationPath.split('/');
+    const changeIndex = Number(pathSegments[pathSegments.length - 2]);
+    const addressIndex = Number(pathSegments[pathSegments.length - 1]);
+
+    // Derive the change key from the master key
+    const changeNode = accountMasterKey.derive(changeIndex).derive(addressIndex);
+    const changePubkey = changeNode.publicKey;
+
+    let changeAddress: string;
+    let changePayment;
+
+    // Create change address based on purpose
+    switch (changePurpose) {
+      case 49: // P2SH-P2WPKH
+        changePayment = utxolib.payments.p2sh({
+          redeem: utxolib.payments.p2wpkh({
+            pubkey: changePubkey,
+            network,
+          }),
+          network,
+        });
+        changeAddress = changePayment.address!;
+        break;
+      case 84: // P2WPKH
+        changePayment = utxolib.payments.p2wpkh({
+          pubkey: changePubkey,
+          network,
+        });
+        changeAddress = changePayment.address!;
+        break;
+      case 86: // P2TR
+        const xOnlyChangePubkey = changePubkey.length === 33 ? changePubkey.subarray(1, 33) : changePubkey;
+        changePayment = utxolib.payments.p2tr(
+          {
+            pubkey: xOnlyChangePubkey,
+            network,
+          },
+          { eccLib: utxolib.ecc }
+        );
+        changeAddress = changePayment.address!;
+        break;
+      default:
+        throw new Error(`Unsupported purpose: ${changePurpose}`);
+    }
+
+    psbt.addOutput({
+      address: changeAddress,
+      value: BigInt(calculatedChangeValue),
+    });
+
+    // Add bip32Derivation to the change output
+    psbt.updateOutput(1, {
+      bip32Derivation: [
+        {
+          masterFingerprint: Buffer.alloc(4, 0),
+          path: changeDerivationPath,
+          pubkey: changePubkey,
+        },
+      ],
+    });
+  }
+
+  return {
+    psbt,
+    masterKey: accountMasterKey,
+    changeDerivationPath,
+    changePurpose,
+  };
+}