test: Add comprehensive BIP86 Taproot derivation path tests

Author: landabaso

test/bip86.test.ts

@@ -1,4 +1,5 @@
-//https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki#user-content-Address_derivation
+// BIP86: Taproot BIP32 Derivation Path and Extended Key Version
+// https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki
 
 import * as ecc from '@bitcoinerlab/secp256k1';
 import { networks } from 'bitcoinjs-lib';
@@ -13,16 +14,58 @@ const masterNode = BIP32.fromSeed(
   ),
   network
 );
-describe('BIP86', () => {
-  test('BIP86', () => {
+
+describe('BIP86 Taproot Derivation Path Tests', () => {
+  // Test vector from BIP86 specification
+  // https://github.com/bitcoin/bips/blob/master/bip-0086.mediawiki#test-vectors
+  
+  test('First receiving address m/86\'/0\'/0\'/0/0', () => {
+    // Account 0, first receiving address = m/86'/0'/0'/0/0
+    // Expected values from BIP86 specification:
+    // xprv = xprvA449goEeU9okwCzzZaxiy475EQGQzBkc65su82nXEvcwzfSskb2hAt2WymrjyRL6kpbVTGL3cKtp9herYXSjjQ1j4stsXXiRF7kXkCacK3T
+    // xpub = xpub6H3W6JmYJXN49h5TfcVjLC3onS6uPeUTTJoVvRC8oG9vsTn2J8LwigLzq5tHbrwAzH9DGo6ThGUdWsqce8dGfwHVBxSbixjDADGGdzF7t2B
+    // internal_key = cc8a4bc64d897bddc5fbc2f670f7a8ba0b386779106cf1223c6fc5d7cd6fc115
+    // output_key = a60869f0dbcf1dc659c9cecbaf8050135ea9e8cdc487053f1dc6880949dc684c
+    // scriptPubKey = 5120a60869f0dbcf1dc659c9cecbaf8050135ea9e8cdc487053f1dc6880949dc684c
+    // address = bc1p5cyxnuxmeuwuvkwfem96lqzszd02n6xdcjrs20cac6yqjjwudpxqkedrcr
+    
+    const descriptor = trBIP32({
+      masterNode,
+      network,
+      account: 0,
+      change: 0,
+      index: 0
+    });
+    
+    const output = new Output({ descriptor, network });
+    const address = output.getAddress();
+    const scriptPubKey = output.getScriptPubKey().toString('hex');
+    
+    // Verify the generated address matches the expected value from BIP86 spec
+    expect(address).toBe('bc1p5cyxnuxmeuwuvkwfem96lqzszd02n6xdcjrs20cac6yqjjwudpxqkedrcr');
+    
+    // Verify the scriptPubKey matches the expected value (with 5120 prefix for OP_PUSHBYTES_32 + 32-byte key)
+    expect(scriptPubKey).toBe('5120a60869f0dbcf1dc659c9cecbaf8050135ea9e8cdc487053f1dc6880949dc684c');
+  });
+  
+  test('Basic Taproot descriptor functionality', () => {
     const descriptor = trBIP32({
       masterNode,
       network,
       account: 0,
       change: 0,
       index: 0
     });
+    
     const output = new Output({ descriptor, network });
-    console.log(output.getAddress());
+    
+    // Verify we can get an address
+    expect(output.getAddress()).toBeTruthy();
+    
+    // Verify it's a Taproot address (starts with bc1p for mainnet)
+    expect(output.getAddress().startsWith('bc1p')).toBe(true);
+    
+    // Verify it's recognized as Taproot
+    expect(output.isTaproot()).toBe(true);
   });
 });