feat(utxo-staking): add test case demonstrating bug #71

This adds a test case to demonstrate an issue where bitcoinjs-lib
incorrectly allows finalization of an invalid transaction.

Shows that the following systems correctly reject the transaction:

* utxolib
* wasm-miniscript
* bitcoind

Issue: BTC-71

Co-authored-by: llm-git <[email protected]>

Author: OttoAllmendinger

modules/utxo-staking/test/unit/babylon/bug71.ts

@@ -0,0 +1,79 @@
+import * as fs from 'fs';
+import assert from 'assert';
+
+import * as bitcoinjs from 'bitcoinjs-lib';
+import * as utxolib from '@bitgo/utxo-lib';
+import * as wasmMiniscript from '@bitgo/wasm-miniscript';
+
+// demonstrate https://github.com/babylonlabs-io/btc-staking-ts/issues/71
+describe('btc-staking-ts bug #71', function () {
+  let buf: Buffer;
+  before('load half-signed transaction', async function () {
+    const fixture = JSON.parse(
+      await fs.promises.readFile(__dirname + '/../../fixtures/babylon/txTree.testnet.json', 'utf-8')
+    );
+    const base64 = fixture.slashingSignedBase64;
+    assert(typeof base64 === 'string');
+    buf = Buffer.from(base64, 'base64');
+  });
+
+  it('can finalize with bitcoinjs-lib', function () {
+    const psbt = bitcoinjs.Psbt.fromBuffer(buf);
+    // this does not throw because of a bug in bitcoinjs-lib
+    psbt.finalizeAllInputs();
+  });
+
+  it('cannot finalize with utxolib', function () {
+    const psbt = utxolib.Psbt.fromBuffer(buf);
+    assert.throws(() => {
+      psbt.finalizeAllInputs();
+    }, /Error: Can not finalize input #0/);
+  });
+
+  it('cannot finalize with wasm-miniscript', function () {
+    const psbt = wasmMiniscript.Psbt.deserialize(buf);
+    assert.throws(() => {
+      psbt.finalize();
+    }, /CouldNotSatisfyTr/);
+  });
+
+  it('cannot finalize with bitcoind', async function (this: Mocha.Context) {
+    let cookie: string;
+    try {
+      cookie = await fs.promises.readFile(process.env.HOME + '/.bitcoin/regtest/.cookie', 'utf-8');
+    } catch (e) {
+      if (e.code === 'ENOENT') {
+        console.log('No cookie file found, skipping test');
+        this.skip();
+      }
+      throw e;
+    }
+    // make regtest JSON-RPC request with cookie
+    const url = 'http://localhost:18443';
+    const headers = {
+      'Content-Type': 'application/json',
+      Authorization: 'Basic ' + Buffer.from(cookie, 'utf-8').toString('base64'),
+    };
+
+    // Create the request payload for finalizepsbt RPC call
+    const body = JSON.stringify({
+      jsonrpc: '1.0',
+      id: 'bitgo-test',
+      method: 'finalizepsbt',
+      params: [buf.toString('base64')],
+    });
+
+    // Make the RPC request
+    const response = await fetch(url, {
+      method: 'POST',
+      headers,
+      body,
+    });
+
+    assert.deepStrictEqual((await response.json()).result, {
+      // the response psbt is the same as the input psbt - not finalized
+      psbt: buf.toString('base64'),
+      complete: false,
+    });
+  });
+});