fix derivation of payment code fom a seed for testnet

src/payment-code.js

@@ -26,9 +26,11 @@ class PaymentCode {
   }
 
   static fromSeed(bSeed, id, network) {
-    var reserved = Buffer.alloc(13, 0);
+    network = network || networks.bitcoin;
+    const reserved = Buffer.alloc(13, 0);
     const root = fromSeed(bSeed);
-    const root_bip47 = root.derivePath(`m/47'/0'/${id}'`);
+    const coinType = (network.pubKeyHash == networks.bitcoin.pubKeyHash) ? '0' : '1';
+    const root_bip47 = root.derivePath(`m/47'/${coinType}'/${id}'`);
 
     let pc = Buffer.from('0100', 'hex'); // version + options
     pc = Buffer.concat([pc, root_bip47.publicKey]);

test/index.js

@@ -83,6 +83,7 @@ describe('payment-code', function() {
         const pc_b58 = pc.toBase58();
         assert(pc_b58 == PC_2.pcBase58);
       } catch(e) {
+        console.log(e)
         assert(false);
       }
     });