Wallet address derivation follows bip32/bitcoinj keychain structure

Also wallet accepts bytes in constructor

[#60]

test/wallet.js

@@ -1,10 +1,17 @@
 var Wallet = require('../src/wallet.js')
+var HDNode = require('../src/hdwallet.js')
+var convert = require('../src/convert.js')
 var assert = require('assert')
+var SHA256 = require('crypto-js/sha256')
+var Crypto = require('crypto-js')
 
 describe('Wallet', function() {
-  var seed = 'crazy horse battery staple'
+  var seed;
+  beforeEach(function(){
+    seed = convert.wordArrayToBytes(SHA256("don't use a string seed like this in real life"))
+  })
 
-  describe('default constructor', function() {
+  describe('constructor', function() {
     var wallet;
     beforeEach(function() {
       wallet = new Wallet(seed)
@@ -14,24 +21,43 @@ describe('Wallet', function() {
       assert.equal(wallet.getMasterKey().network, 'mainnet')
     })
 
-    it('defaults to private derivationMethod', function() {
-      assert.equal(wallet.derivationMethod, 'private')
+    it("generates m/0' as the main account", function() {
+      var mainAccount = wallet.accountZero
+      assert.equal(mainAccount.index, 0 + HDNode.HIGHEST_BIT)
+      assert.equal(mainAccount.depth, 1)
+    })
+
+    it("generates m/0'/0 as the external account", function() {
+      var account = wallet.externalAccount
+      assert.equal(account.index, 0)
+      assert.equal(account.depth, 2)
+    })
+
+    it("generates m/0'/1 as the internal account", function() {
+      var account = wallet.internalAccount
+      assert.equal(account.index, 1)
+      assert.equal(account.depth, 2)
+    })
+
+    describe('constructor options', function() {
+      var wallet;
+      beforeEach(function() {
+        wallet = new Wallet(seed, {network: 'testnet'})
+      })
+
+      it('uses the network if specified', function() {
+        assert.equal(wallet.getMasterKey().network, 'testnet')
+      })
     })
   })
 
-  describe('constructor options', function() {
+  describe('generateAddress', function(){
     var wallet;
-    beforeEach(function() {
-      wallet = new Wallet(seed, {network: 'testnet', derivationMethod: 'public'})
-    })
+    beforeEach(function() { wallet = new Wallet(seed, {network: 'testnet'}) })
 
-    it('uses the network if specified', function() {
-      assert.equal(wallet.getMasterKey().network, 'testnet')
-    })
-
-    it('uses the derivationMethod if specified', function() {
-      assert.equal(wallet.derivationMethod, 'public')
+    it('defaults to generating receiving addresses', function(){
+      assert.equal(wallet.generateAddress(), "n1GyUANZand9Kw6hGSV9837cCC9FFUQzQa")
+      assert.equal(wallet.generateAddress(), "n2fiWrHqD6GM5GiEqkbWAc6aaZQp3ba93X")
     })
   })
-
 })