feat(utxo-staking): add test for babylon delegation message

OttoAllmendinger · OttoAllmendinger · commit d1bf8c3083b6 · 2025-03-07T12:16:13.000+01:00
Add test which checks MsgCreateBTCDelegation creation using vendored module staking implementation. Issue: BTC-1826
diff --git a/modules/utxo-staking/src/babylon/descriptor.ts b/modules/utxo-staking/src/babylon/descriptor.ts
@@ -1,3 +1,8 @@
+/**
+ * https://github.com/babylonlabs-io/babylon/tree/main/docs
+ * https://github.com/babylonlabs-io/babylon/blob/main/docs/staking-script.md
+ */
+
 import { Descriptor, ast } from '@bitgo/wasm-miniscript';
 
 export function getUnspendableKey(): string {
diff --git a/modules/utxo-staking/src/babylon/testnet.ts b/modules/utxo-staking/src/babylon/testnet.ts
@@ -4,6 +4,7 @@ import { BabylonDescriptorBuilder } from './descriptor';
 
 // Source: https://github.com/babylonlabs-io/babylon/blob/v1.99.0-snapshot.250211/app/upgrades/v1/testnet/btcstaking_params.go#L149-L159
 export const testnetStakingParams = {
+  version: 5 /* it's the sixth element in the array */,
   covenant_pks: [
     'fa9d882d45f4060bdb8042183828cd87544f1ea997380e586cab77d5fd698737',
     '0aee0509b16db71c999238a4827db945526859b13c95487ab46725357c9a9f25',
diff --git a/modules/utxo-staking/test/fixtures/babylon/msgCreateBTCDelegation.testnet.json b/modules/utxo-staking/test/fixtures/babylon/msgCreateBTCDelegation.testnet.json
@@ -0,0 +1,47 @@
+{
+  "msg": {
+    "stakerAddr": "bbn1qw3jhxaqax8rcq",
+    "pop": {
+      "btcSigType": 2,
+      "btcSig": "77d73c7deef77de75f6dc79cddaf7c7f8f3aedbddcd36f787f6d35d37dfaf5d7dbdb46b9efb71e71de79f3cf74e7a6b7e9ff7475ae3c6da7dc7b9e7ae9cf74e1deb46dc6dcd5bd377b6df6e3be7475feddf3d71bd7c7757fa7dc6ddd3adf4ddb"
+    },
+    "btcPk": "7b6a08504c46336f985a5787a5423eb18c10b149fef29cd3316ad86f565cd2b9",
+    "fpBtcPkList": [
+      "d23c2c25e1fcf8fd1c21b9a402c19e2e309e531e45e92fb1e9805b6056b0cc76"
+    ],
+    "stakingTime": 10000,
+    "stakingValue": 55555,
+    "stakingTx": "020000000111111111111111111111111111111111111111111111111111111111111111110000000000ffffffff0203d9000000000000225120f1871fc2ac3050b53dc35d502a9d94388f6f373b86f3905667945a8430cbd639bf51090000000000160014896f1ba65deaeb045bb3121e20e5744e66ca0e4800000000",
+    "slashingTx": "020000000164da14050ffd0e6186c68a59f371a0adc95cc84b0502fe0915be7eba3f771bb30000000000ffffffff02d90a0000000000001600145be12624d08a2b424095d7c07221c33450d14bf1a2ba000000000000225120d5238530e223ef1bd34a8a98ee1708f6a8a87e7a2589d88de6700b9973ffff4600000000",
+    "delegatorSlashingSig": "f10a5e6d722b459e87d713bf9af1113fa5eb7a1e41ff5738de7049fcf113beaa5f01228aecf27eb94045a9900b092091a63dbf546fd7d6c05d32d32cf8ad591d",
+    "unbondingTime": 1008,
+    "unbondingTx": "020000000164da14050ffd0e6186c68a59f371a0adc95cc84b0502fe0915be7eba3f771bb30000000000ffffffff0133d10000000000002251204dcea0c802236110602d7b1cc2e76ef5f1f05170b058685b4caf4367ac849d6b00000000",
+    "unbondingValue": 53555,
+    "unbondingSlashingTx": "0200000001c047c5904542017cfee57fdb350d6bf776a5ef8c46bc033f454a64b496d0ab9d0000000000ffffffff02750a0000000000001600145be12624d08a2b424095d7c07221c33450d14bf136b3000000000000225120d5238530e223ef1bd34a8a98ee1708f6a8a87e7a2589d88de6700b9973ffff4600000000",
+    "delegatorUnbondingSlashingSig": "5bf9bed637fbd109d53c60df4093b166ba06a27b90c6b7d05beb9124a19fc62d1d17522a309d4dd7d8dc2eed954dcb3f628f44ae9837c02b91545fa313de6e17"
+  },
+  "msgBytes": "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",
+  "stakingTx": {
+    "version": 2,
+    "locktime": 0,
+    "ins": [
+      {
+        "hash": "1111111111111111111111111111111111111111111111111111111111111111",
+        "index": 0,
+        "script": "",
+        "sequence": 4294967295,
+        "witness": []
+      }
+    ],
+    "outs": [
+      {
+        "script": "5120f1871fc2ac3050b53dc35d502a9d94388f6f373b86f3905667945a8430cbd639",
+        "value": 55555
+      },
+      {
+        "script": "0014896f1ba65deaeb045bb3121e20e5744e66ca0e48",
+        "value": 610751
+      }
+    ]
+  }
+}
diff --git a/modules/utxo-staking/test/fixtures/babylon/msgCreateBTCDelegation.testnetMock.json b/modules/utxo-staking/test/fixtures/babylon/msgCreateBTCDelegation.testnetMock.json
@@ -0,0 +1,47 @@
+{
+  "msg": {
+    "stakerAddr": "bbn1qw3jhxaqax8rcq",
+    "pop": {
+      "btcSigType": 2,
+      "btcSig": "77d73c7deef77de75f6dc79cddaf7c7f8f3aedbddcd36f787f6d35d37dfaf5d7dbdb46b9efb71e71de79f3cf74e7a6b7e9ff7475ae3c6da7dc7b9e7ae9cf74e1deb46dc6dcd5bd377b6df6e3be7475feddf3d71bd7c7757fa7dc6ddd3adf4ddb"
+    },
+    "btcPk": "7b6a08504c46336f985a5787a5423eb18c10b149fef29cd3316ad86f565cd2b9",
+    "fpBtcPkList": [
+      "850854d26df93570748d94e3da361f134c522f7970bd7f8701a164547308a900"
+    ],
+    "stakingTime": 10000,
+    "stakingValue": 55555,
+    "stakingTx": "020000000111111111111111111111111111111111111111111111111111111111111111110000000000ffffffff0203d9000000000000225120788d73d75d7dd88d3612f7a91d5b3d6ad4778d8b49176f9539d322980b2f4fd7bf51090000000000160014896f1ba65deaeb045bb3121e20e5744e66ca0e4800000000",
+    "slashingTx": "0200000001a999d7bc6af1a17cd4e70d0fd875a1734152dfb55f9166240f35965c79fa36c20000000000ffffffff02d90a0000000000001600145be12624d08a2b424095d7c07221c33450d14bf1a2ba000000000000225120d5238530e223ef1bd34a8a98ee1708f6a8a87e7a2589d88de6700b9973ffff4600000000",
+    "delegatorSlashingSig": "c032a98f7d16adc8a1438310782b35aa0e5d23abca1deb1d743461e7649e0cca07b030c2f083ffb21b88b8de1198a919853b576a7e9c4b80f5bcd6cb544536b4",
+    "unbondingTime": 1008,
+    "unbondingTx": "0200000001a999d7bc6af1a17cd4e70d0fd875a1734152dfb55f9166240f35965c79fa36c20000000000ffffffff0133d1000000000000225120dec7bc887b110e2c10f1c9a2212cd961e95184870c91d88c9a3727f4ef4c303c00000000",
+    "unbondingValue": 53555,
+    "unbondingSlashingTx": "02000000014c2a294c5e31886937d0985e69e65314419e8866e5ab859cb2903cbe420a555a0000000000ffffffff02750a0000000000001600145be12624d08a2b424095d7c07221c33450d14bf136b3000000000000225120d5238530e223ef1bd34a8a98ee1708f6a8a87e7a2589d88de6700b9973ffff4600000000",
+    "delegatorUnbondingSlashingSig": "71fdbb1e85db78b2406f7f6a8bbbeecd9be27d6099c4b80b2cf09403a855b55d057805576afad3bf92b79487e9559ad355c9728f95fe191c7a78b21284925fd0"
+  },
+  "msgBytes": "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",
+  "stakingTx": {
+    "version": 2,
+    "locktime": 0,
+    "ins": [
+      {
+        "hash": "1111111111111111111111111111111111111111111111111111111111111111",
+        "index": 0,
+        "script": "",
+        "sequence": 4294967295,
+        "witness": []
+      }
+    ],
+    "outs": [
+      {
+        "script": "5120788d73d75d7dd88d3612f7a91d5b3d6ad4778d8b49176f9539d322980b2f4fd7",
+        "value": 55555
+      },
+      {
+        "script": "0014896f1ba65deaeb045bb3121e20e5744e66ca0e48",
+        "value": 610751
+      }
+    ]
+  }
+}
diff --git a/modules/utxo-staking/test/unit/babylon/key.utils.ts b/modules/utxo-staking/test/unit/babylon/key.utils.ts
@@ -0,0 +1,30 @@
+import assert from 'assert';
+
+import * as utxolib from '@bitgo/utxo-lib';
+import { ECPairInterface } from '@bitgo/utxo-lib';
+import { getKey } from '@bitgo/utxo-core/testutil';
+
+export function getECKey(seed: string): ECPairInterface {
+  const { privateKey } = getKey(seed);
+  assert(privateKey);
+  return utxolib.ECPair.fromPrivateKey(privateKey);
+}
+
+export function getECKeys(key: string, count: number): ECPairInterface[] {
+  return Array.from({ length: count }, (_, i) => getECKey(`${key}${i}`));
+}
+
+export function getXOnlyPubkey(key: ECPairInterface): Buffer {
+  return key.publicKey.subarray(1);
+}
+
+export function fromXOnlyPublicKey(key: Buffer): ECPairInterface {
+  for (const prefix of [0x02, 0x03]) {
+    try {
+      return utxolib.ECPair.fromPublicKey(Buffer.concat([Buffer.from([prefix]), key]));
+    } catch {
+      continue;
+    }
+  }
+  throw new Error('Invalid x-only public key');
+}
diff --git a/modules/utxo-staking/test/unit/babylon/transaction.utils.ts b/modules/utxo-staking/test/unit/babylon/transaction.utils.ts
@@ -0,0 +1,40 @@
+import assert from 'assert';
+
+import * as bitcoinjslib from 'bitcoinjs-lib';
+import { Descriptor } from '@bitgo/wasm-miniscript';
+import { ECPairInterface } from '@bitgo/utxo-lib';
+import { toWrappedPsbt } from '@bitgo/utxo-core/descriptor';
+
+export function getSignedPsbt(
+  psbt: bitcoinjslib.Psbt,
+  descriptor: Descriptor,
+  signers: ECPairInterface[],
+  { finalize = false }
+): bitcoinjslib.Psbt {
+  const wrappedPsbt = toWrappedPsbt(psbt.toBuffer());
+  const signedInputs = psbt.data.inputs.flatMap((input, i) => {
+    assert(input.witnessUtxo);
+    if (Buffer.from(descriptor.scriptPubkey()).equals(input.witnessUtxo.script)) {
+      wrappedPsbt.updateInputWithDescriptor(i, descriptor);
+      const signResults = signers.map((signer) => {
+        assert(signer.privateKey);
+        return wrappedPsbt.signWithPrv(signer.privateKey);
+      });
+      return [[i, signResults]];
+    }
+    return [];
+  });
+  assert(signedInputs.length > 0);
+  if (finalize) {
+    wrappedPsbt.finalize();
+  }
+  return bitcoinjslib.Psbt.fromBuffer(Buffer.from(wrappedPsbt.serialize()));
+}
+
+export function getSignedExtract(
+  psbt: bitcoinjslib.Psbt,
+  descriptor: Descriptor,
+  signers: ECPairInterface[]
+): bitcoinjslib.Transaction {
+  return getSignedPsbt(psbt, descriptor, signers, { finalize: true }).extractTransaction();
+}
diff --git a/modules/utxo-staking/test/unit/babylon/transactions.ts b/modules/utxo-staking/test/unit/babylon/transactions.ts
@@ -5,41 +5,22 @@ import * as bitcoinjslib from 'bitcoinjs-lib';
 import * as utxolib from '@bitgo/utxo-lib';
 import { ECPairInterface } from '@bitgo/utxo-lib';
 import { ast, Descriptor, Miniscript } from '@bitgo/wasm-miniscript';
-import { createAddressFromDescriptor, toWrappedPsbt } from '@bitgo/utxo-core/descriptor';
-import { getFixture, getKey, toPlainObject } from '@bitgo/utxo-core/testutil';
+import { createAddressFromDescriptor } from '@bitgo/utxo-core/descriptor';
+import { getFixture, toPlainObject } from '@bitgo/utxo-core/testutil';
 
 import { BabylonDescriptorBuilder, finalityBabylonProvider0, testnetStakingParams } from '../../../src/babylon';
 import { normalize } from '../fixtures.utils';
 
-bitcoinjslib.initEccLib(utxolib.ecc);
-
-function getECKey(seed: string): ECPairInterface {
-  const { privateKey } = getKey(seed);
-  assert(privateKey);
-  return utxolib.ECPair.fromPrivateKey(privateKey);
-}
+import { getSignedExtract } from './transaction.utils';
+import { fromXOnlyPublicKey, getECKey, getECKeys, getXOnlyPubkey } from './key.utils';
+import { getVendorMsgCreateBtcDelegation } from './vendor.utils';
 
-function getECKeys(key: string, count: number): ECPairInterface[] {
-  return Array.from({ length: count }, (_, i) => getECKey(`${key}${i}`));
-}
-
-function getXOnlyPubkey(key: ECPairInterface): Buffer {
-  return key.publicKey.subarray(1);
-}
-
-function fromXOnlyPublicKey(key: Buffer): ECPairInterface {
-  for (const prefix of [0x02, 0x03]) {
-    try {
-      return utxolib.ECPair.fromPublicKey(Buffer.concat([Buffer.from([prefix]), key]));
-    } catch {
-      continue;
-    }
-  }
-  throw new Error('Invalid x-only public key');
-}
+bitcoinjslib.initEccLib(utxolib.ecc);
 
-function getTestnetStakingParams(): vendor.StakingParams {
+function getTestnetStakingParams(): vendor.VersionedStakingParams {
   return {
+    version: testnetStakingParams.version,
+    btcActivationHeight: testnetStakingParams.btc_activation_height,
     covenantNoCoordPks: testnetStakingParams.covenant_pks,
     covenantQuorum: testnetStakingParams.covenant_quorum,
     unbondingTime: testnetStakingParams.unbonding_time_blocks,
@@ -73,29 +54,6 @@ type TransactionTree = {
   slashingWithdraw: PsbtWithFee | undefined;
 };
 
-function getSigned(
-  psbt: bitcoinjslib.Psbt,
-  descriptor: Descriptor,
-  signers: ECPairInterface[]
-): bitcoinjslib.Transaction {
-  const wrappedPsbt = toWrappedPsbt(psbt.toBuffer());
-  const signedInputs = psbt.data.inputs.flatMap((input, i) => {
-    assert(input.witnessUtxo);
-    if (Buffer.from(descriptor.scriptPubkey()).equals(input.witnessUtxo.script)) {
-      wrappedPsbt.updateInputWithDescriptor(i, descriptor);
-      const signResults = signers.map((signer) => {
-        assert(signer.privateKey);
-        return wrappedPsbt.signWithPrv(signer.privateKey);
-      });
-      return [[i, signResults]];
-    }
-    return [];
-  });
-  assert(signedInputs.length > 0);
-  wrappedPsbt.finalize();
-  return bitcoinjslib.Psbt.fromBuffer(Buffer.from(wrappedPsbt.serialize())).extractTransaction();
-}
-
 function getStakingTransactionTreeVendor(
   builder: vendor.Staking,
   amount: number,
@@ -119,14 +77,14 @@ function getStakingTransactionTreeVendor(
   const signSequence = signers ? [signers.staker, signers.finalityProvider, ...signers.covenant] : undefined;
   const unbondingSlashingWithdraw = signSequence
     ? builder.createWithdrawSlashingPsbt(
-        getSigned(unbondingSlashing.psbt, descriptorBuilder.getUnbondingDescriptor(), signSequence),
+        getSignedExtract(unbondingSlashing.psbt, descriptorBuilder.getUnbondingDescriptor(), signSequence),
         feeRateSatB
       )
     : undefined;
   const slashing = builder.createStakingOutputSlashingPsbt(staking.transaction);
   const slashingWithdraw = signSequence
     ? builder.createWithdrawSlashingPsbt(
-        getSigned(slashing.psbt, descriptorBuilder.getStakingDescriptor(), signSequence),
+        getSignedExtract(slashing.psbt, descriptorBuilder.getStakingDescriptor(), signSequence),
         feeRateSatB
       )
     : undefined;
@@ -143,7 +101,7 @@ function getStakingTransactionTreeVendor(
   };
 }
 
-function getTestnetStakingParamsWithCovenant(covenantKeys: ECPairInterface[]): vendor.StakingParams {
+function getTestnetStakingParamsWithCovenant(covenantKeys: ECPairInterface[]): vendor.VersionedStakingParams {
   return {
     ...getTestnetStakingParams(),
     covenantNoCoordPks: covenantKeys.map((pk) => getXOnlyPubkey(pk).toString('hex')),
@@ -189,6 +147,7 @@ function parseScripts(scripts: unknown) {
 }
 
 async function assertEqualsFixture(fixtureName: string, value: unknown): Promise<void> {
+  value = normalize(value);
   assert.deepStrictEqual(await getFixture(fixtureName, value), value);
 }
 
@@ -245,7 +204,7 @@ function describeWithKeys(
   tag: string,
   finalityProviderKeys: ECPairInterface[],
   covenantKeys: ECPairInterface[],
-  stakingParams: vendor.StakingParams,
+  stakingParams: vendor.VersionedStakingParams,
   { signIntermediateTxs = false } = {}
 ) {
   const stakerKey = getECKey('staker');
@@ -331,13 +290,13 @@ function describeWithKeys(
         ]);
       });
 
-      it('has expected transactions (vendorStaking.Staking)', async function (this: Mocha.Context) {
-        if (finalityProviderKeys.length !== 1) {
-          this.skip();
-        }
+      if (finalityProviderKeys.length !== 1) {
+        return;
+      }
 
-        const finalityProvider = finalityProviderKeys[0];
+      const finalityProvider = finalityProviderKeys[0];
 
+      it('has expected transactions (vendorStaking.Staking)', async function (this: Mocha.Context) {
         const vendorStakingTxBuilder = new vendor.Staking(
           bitcoinjslib.networks.bitcoin,
           {
@@ -366,14 +325,30 @@ function describeWithKeys(
         );
         await assertTransactionEqualsFixture(`test/fixtures/babylon/txTree.${tag}.json`, txTree);
       });
+
+      it('creates MsgCreateBTCDelegation', async function () {
+        await assertEqualsFixture(
+          `test/fixtures/babylon/msgCreateBTCDelegation.${tag}.json`,
+          await getVendorMsgCreateBtcDelegation(
+            stakerKey,
+            finalityProvider,
+            descriptorBuilder,
+            stakingParams,
+            changeAddress,
+            amount,
+            utxo,
+            feeRateSatB
+          )
+        );
+      });
     });
   });
 }
 
 function describeWithKeysFromStakingParams(
   tag: string,
   finalityProviderKeys: ECPairInterface[],
-  stakingParams: vendor.StakingParams
+  stakingParams: vendor.VersionedStakingParams
 ) {
   describeWithKeys(
     tag,
diff --git a/modules/utxo-staking/test/unit/babylon/vendor.utils.ts b/modules/utxo-staking/test/unit/babylon/vendor.utils.ts
diff --git a/modules/utxo-staking/test/unit/fixtures.utils.ts b/modules/utxo-staking/test/unit/fixtures.utils.ts
