refactor(utxo-staking): add toDescriptor helper for descriptor type handling

Add DescriptorLike type and toDescriptor helper function to improve code
readability and reduce duplicate conversion logic in undelegation tests.

Issue: BTC-2143

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

Author: OttoAllmendinger

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

@@ -27,7 +27,15 @@ async function getFixture(txid: string): Promise<UndelegationResponse> {
   return result.right.btc_delegation.undelegation_response;
 }
 
-function runTest(network: utxolib.Network, txid: string, descriptor: Descriptor | ast.DescriptorNode | string): void {
+type DescriptorLike = Descriptor | ast.DescriptorNode | string;
+
+function toDescriptor(descriptor: DescriptorLike): Descriptor {
+  return descriptor instanceof Descriptor
+    ? descriptor
+    : Descriptor.fromStringDetectType(typeof descriptor === 'string' ? descriptor : ast.formatNode(descriptor));
+}
+
+function runTest(network: utxolib.Network, txid: string, descriptor: Descriptor): void {
   describe(`Unbonding transaction ${txid}`, function () {
     it('should create a PSBT from the unbonding transaction', async function () {
       const fixture = await getFixture(txid);
@@ -37,11 +45,6 @@ function runTest(network: utxolib.Network, txid: string, descriptor: Descriptor
       });
       const signatures = fixture.covenant_unbonding_sig_list.map((sig) => toPartialSig(sig));
 
-      descriptor =
-        descriptor instanceof Descriptor
-          ? descriptor
-          : Descriptor.fromStringDetectType(typeof descriptor === 'string' ? descriptor : ast.formatNode(descriptor));
-
       const psbt = toUnbondingPsbtWithSignatures(
         tx,
         {
@@ -63,38 +66,21 @@ function runTest(network: utxolib.Network, txid: string, descriptor: Descriptor
   });
 }
 
-runTest(utxolib.networks.bitcoinPublicSignet, '5d277e1b29e5589074aea95ac8c8230fd911c2ec3c58774aafdef915619b772c', {
-  tr: [
-    '50929b74c1a04954b78b4b6035e97a5e078a5a0f28ec96d547bfee9ace803ac0',
-    [
-      {
-        and_v: [
-          {
-            and_v: [
-              { 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' },
-              { 'v:pk': 'd23c2c25e1fcf8fd1c21b9a402c19e2e309e531e45e92fb1e9805b6056b0cc76' },
-            ],
-          },
-          {
-            multi_a: [
-              6,
-              '0aee0509b16db71c999238a4827db945526859b13c95487ab46725357c9a9f25',
-              '113c3a32a9d320b72190a04a020a0db3976ef36972673258e9a38a364f3dc3b0',
-              '17921cf156ccb4e73d428f996ed11b245313e37e27c978ac4d2cc21eca4672e4',
-              '3bb93dfc8b61887d771f3630e9a63e97cbafcfcc78556a474df83a31a0ef899c',
-              '40afaf47c4ffa56de86410d8e47baa2bb6f04b604f4ea24323737ddc3fe092df',
-              '79a71ffd71c503ef2e2f91bccfc8fcda7946f4653cef0d9f3dde20795ef3b9f0',
-              'd21faf78c6751a0d38e6bd8028b907ff07e9a869a43fc837d6b3f8dff6119a36',
-              'f5199efae3f28bb82476163a7e458c7ad445d9bffb0682d10d3bdb2cb41f8e8e',
-              'fa9d882d45f4060bdb8042183828cd87544f1ea997380e586cab77d5fd698737',
-            ],
-          },
-        ],
-      },
+runTest(
+  utxolib.networks.bitcoinPublicSignet,
+  '5d277e1b29e5589074aea95ac8c8230fd911c2ec3c58774aafdef915619b772c',
+  toDescriptor({
+    tr: [
+      '50929b74c1a04954b78b4b6035e97a5e078a5a0f28ec96d547bfee9ace803ac0',
       [
         {
           and_v: [
-            { 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' },
+            {
+              and_v: [
+                { 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' },
+                { 'v:pk': 'd23c2c25e1fcf8fd1c21b9a402c19e2e309e531e45e92fb1e9805b6056b0cc76' },
+              ],
+            },
             {
               multi_a: [
                 6,
@@ -111,8 +97,29 @@ runTest(utxolib.networks.bitcoinPublicSignet, '5d277e1b29e5589074aea95ac8c8230fd
             },
           ],
         },
-        { and_v: [{ 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' }, { older: 10000 }] },
+        [
+          {
+            and_v: [
+              { 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' },
+              {
+                multi_a: [
+                  6,
+                  '0aee0509b16db71c999238a4827db945526859b13c95487ab46725357c9a9f25',
+                  '113c3a32a9d320b72190a04a020a0db3976ef36972673258e9a38a364f3dc3b0',
+                  '17921cf156ccb4e73d428f996ed11b245313e37e27c978ac4d2cc21eca4672e4',
+                  '3bb93dfc8b61887d771f3630e9a63e97cbafcfcc78556a474df83a31a0ef899c',
+                  '40afaf47c4ffa56de86410d8e47baa2bb6f04b604f4ea24323737ddc3fe092df',
+                  '79a71ffd71c503ef2e2f91bccfc8fcda7946f4653cef0d9f3dde20795ef3b9f0',
+                  'd21faf78c6751a0d38e6bd8028b907ff07e9a869a43fc837d6b3f8dff6119a36',
+                  'f5199efae3f28bb82476163a7e458c7ad445d9bffb0682d10d3bdb2cb41f8e8e',
+                  'fa9d882d45f4060bdb8042183828cd87544f1ea997380e586cab77d5fd698737',
+                ],
+              },
+            ],
+          },
+          { and_v: [{ 'v:pk': '1b443f34ddc1bbaef52a8c5162dfa5a84524636ec745292f949470369ee67391' }, { older: 10000 }] },
+        ],
       ],
     ],
-  ],
-});
+  })
+);