test: add tests for taptree conversion to tapleaf

Author: motorina0

src/psbt/bip371.js

@@ -79,6 +79,10 @@ exports.tweakInternalPubKey = tweakInternalPubKey;
  * @returns a list of BIP 371 tapleaves
  */
 function tapTreeToList(tree) {
+  if (!(0, types_1.isTaptree)(tree))
+    throw new Error(
+      'Cannot convert taptree to tapleaf list. Expecting a tapree structure.',
+    );
   return _tapTreeToList(tree);
 }
 exports.tapTreeToList = tapTreeToList;

src/types.js

@@ -70,7 +70,7 @@ exports.Network = exports.typeforce.compile({
 });
 exports.TAPLEAF_VERSION_MASK = 0xfe;
 function isTapleaf(o) {
-  if (!('output' in o)) return false;
+  if (!o || !('output' in o)) return false;
   if (!buffer_1.Buffer.isBuffer(o.output)) return false;
   if (o.version !== undefined)
     return (o.version & exports.TAPLEAF_VERSION_MASK) === o.version;

test/payments.utils.ts

@@ -186,11 +186,14 @@ export function from(path: string, object: any, result?: any): any {
   return result;
 }
 
-function convertScriptTree(scriptTree: any): any {
-  if (Array.isArray(scriptTree)) return scriptTree.map(convertScriptTree);
+export function convertScriptTree(scriptTree: any, leafVersion?: number): any {
+  if (Array.isArray(scriptTree))
+    return scriptTree.map(t => convertScriptTree(t, leafVersion));
 
   const script = Object.assign({}, scriptTree);
-  if (typeof script.output === 'string')
+  if (typeof script.output === 'string') {
     script.output = asmToBuffer(scriptTree.output);
+    script.version = script.version || leafVersion;
+  }
   return script;
 }

test/psbt.spec.ts

@@ -5,6 +5,10 @@ import * as crypto from 'crypto';
 import ECPairFactory from 'ecpair';
 import { describe, it } from 'mocha';
 
+import { convertScriptTree } from './payments.utils';
+import { LEAF_VERSION_TAPSCRIPT } from '../src/payments/taprootutils';
+import { tapTreeToList, tapTreeFromList } from '../src/psbt/bip371';
+import { Taptree } from '../src/types';
 import { initEccLib } from '../src';
 
 const bip32 = BIP32Factory(ecc);
@@ -13,6 +17,7 @@ const ECPair = ECPairFactory(ecc);
 import { networks as NETWORKS, payments, Psbt, Signer, SignerAsync } from '..';
 
 import * as preFixtures from './fixtures/psbt.json';
+import * as taprootFixtures from './fixtures/p2tr.json';
 
 const validator = (
   pubkey: Buffer,
@@ -1099,6 +1104,67 @@ describe(`Psbt`, () => {
     });
   });
 
+  describe('tapTreeToList/tapTreeFromList', () => {
+    it('Correctly converts a Taptree to a Tapleaf list and back', () => {
+      taprootFixtures.valid
+        .filter(f => f.arguments.scriptTree)
+        .map(f => f.arguments.scriptTree)
+        .forEach(scriptTree => {
+          const originalTree = convertScriptTree(
+            scriptTree,
+            LEAF_VERSION_TAPSCRIPT,
+          );
+          const list = tapTreeToList(originalTree);
+          const treeFromList = tapTreeFromList(list);
+
+          assert.deepStrictEqual(treeFromList, originalTree);
+        });
+    });
+    it('Throws if too many leaves on a given level', () => {
+      const list = Array.from({ length: 5 }).map(() => ({
+        depth: 2,
+        leafVersion: LEAF_VERSION_TAPSCRIPT,
+        script: Buffer.from([]),
+      }));
+      assert.throws(() => {
+        tapTreeFromList(list);
+      }, new RegExp('No room left to insert tapleaf in tree'));
+    });
+    it('Throws if taptree depth is exceeded', () => {
+      let tree: Taptree = [
+        { output: Buffer.from([]) },
+        { output: Buffer.from([]) },
+      ];
+      Array.from({ length: 129 }).forEach(
+        () => (tree = [tree, { output: Buffer.from([]) }]),
+      );
+      assert.throws(() => {
+        tapTreeToList(tree as Taptree);
+      }, new RegExp('Max taptree depth exceeded.'));
+    });
+    it('Throws if tapleaf depth is to high', () => {
+      const list = [
+        {
+          depth: 129,
+          leafVersion: LEAF_VERSION_TAPSCRIPT,
+          script: Buffer.from([]),
+        },
+      ];
+      assert.throws(() => {
+        tapTreeFromList(list);
+      }, new RegExp('Max taptree depth exceeded.'));
+    });
+    it('Throws if not a valid taptree structure', () => {
+      const tree = Array.from({ length: 3 }).map(() => ({
+        output: Buffer.from([]),
+      }));
+
+      assert.throws(() => {
+        tapTreeToList(tree as Taptree);
+      }, new RegExp('Cannot convert taptree to tapleaf list. Expecting a tapree structure.'));
+    });
+  });
+
   describe('getFeeRate', () => {
     it('Throws error if called before inputs are finalized', () => {
       const f = fixtures.getFeeRate;

ts_src/psbt/bip371.ts

@@ -1,4 +1,4 @@
-import { Taptree, Tapleaf, isTapleaf } from '../types';
+import { Taptree, Tapleaf, isTapleaf, isTaptree } from '../types';
 import {
   PsbtInput,
   TapLeafScript,
@@ -111,6 +111,10 @@ export function tweakInternalPubKey(
  * @returns a list of BIP 371 tapleaves
  */
 export function tapTreeToList(tree: Taptree): TapLeaf[] {
+  if (!isTaptree(tree))
+    throw new Error(
+      'Cannot convert taptree to tapleaf list. Expecting a tapree structure.',
+    );
   return _tapTreeToList(tree);
 }
 

ts_src/types.ts

@@ -79,7 +79,7 @@ export interface Tapleaf {
 
 export const TAPLEAF_VERSION_MASK = 0xfe;
 export function isTapleaf(o: any): o is Tapleaf {
-  if (!('output' in o)) return false;
+  if (!o || !('output' in o)) return false;
   if (!NBuffer.isBuffer(o.output)) return false;
   if (o.version !== undefined)
     return (o.version & TAPLEAF_VERSION_MASK) === o.version;