diff --git a/lib/server.js b/lib/server.js
index 2c9079d..b9fdb40 100644
--- a/lib/server.js
+++ b/lib/server.js
@@ -19,10 +19,12 @@ var TxProposal = require('./model/txproposal');
 /**
  * Creates an instance of the Copay server.
  * @constructor
+ * @param {Object} opts
+ * @param {Storage} [opts.storage] - The storage provider.
  */
 function CopayServer(opts) {
 	opts = opts || {};
-	this.storage = new Storage(opts);
+	this.storage = opts.storage || new Storage();
 };
 
 
@@ -81,7 +83,7 @@ CopayServer.prototype.createWallet = function (opts, cb) {
 };
 
 
-CopayServer.prototype.runLocked = function (walletId, cb, task) {
+CopayServer.prototype._runLocked = function (walletId, cb, task) {
 	var self = this;
 
 	Lock.get(walletId, function (lock) {
@@ -105,13 +107,12 @@ CopayServer.prototype.runLocked = function (walletId, cb, task) {
  CopayServer.prototype.joinWallet = function (opts, cb) {
 	var self = this;
 
-	self.runLocked(opts.walletId, cb, function (cb) {
+	self._runLocked(opts.walletId, cb, function (cb) {
 		self.getWallet({ id: opts.walletId, includeCopayers: true }, function (err, wallet) {
 			if (err) return cb(err);
 			if (!wallet) return cb('Wallet not found');
 			if (_.find(wallet.copayers, { xPubKey: opts.xPubKey })) return cb('Copayer already in wallet');
 			if (wallet.copayers.length == wallet.n) return cb('Wallet full');
-
 			// TODO: validate copayer's extended public key using the public key from this wallet
 			// Note: use Bitcore.crypto.ecdsa .verify()
 
@@ -149,19 +150,21 @@ CopayServer.prototype._doCreateAddress = function (pkr, index, isChange) {
  CopayServer.prototype.createAddress = function (opts, cb) {
 	var self = this;
 
-	self.getWallet({ id: opts.walletId }, function (err, wallet) {
-		if (err) return cb(err);
-		if (!wallet) return cb('Wallet not found');
-	
-		var index = wallet.addressIndex++;
-		self.storage.storeWallet(wallet, function (err) {
+	self._runLocked(opts.walletId, cb, function (cb) {
+		self.getWallet({ id: opts.walletId }, function (err, wallet) {
 			if (err) return cb(err);
-
-			var address = self._doCreateAddress(wallet.publicKeyRing, index, opts.isChange);
-			self.storage.storeAddress(opts.walletId, address, function (err) {
+			if (!wallet) return cb('Wallet not found');
+		
+			var index = wallet.addressIndex++;
+			self.storage.storeWallet(wallet, function (err) {
 				if (err) return cb(err);
 
-				return cb(null, address);
+				var address = self._doCreateAddress(wallet.publicKeyRing, index, opts.isChange);
+				self.storage.storeAddress(opts.walletId, address, function (err) {
+					if (err) return cb(err);
+
+					return cb(null, address);
+				});
 			});
 		});
 	});
diff --git a/test/integration.js b/test/integration.js
index b2a7ab2..2312ec9 100644
--- a/test/integration.js
+++ b/test/integration.js
@@ -9,23 +9,26 @@ var should = chai.should();
 var levelup = require('levelup');
 var memdown = require('memdown');
 
+var Storage = require('../lib/storage');
+
 var Wallet = require('../lib/model/wallet');
 var Address = require('../lib/model/address');
 var Copayer = require('../lib/model/copayer');
 var CopayServer = require('../lib/server');
 
-var db;
+var db, storage;
 var server;
 
 describe('Copay server', function() {
   beforeEach(function() {
     db = levelup(memdown, { valueEncoding: 'json' });
+    storage = new Storage({ db: db });
   });
 
   describe('#getWallet', function() {
     beforeEach(function() {
       server = new CopayServer({
-        db: db,
+        storage: storage,
       });
     });
 
@@ -102,7 +105,7 @@ describe('Copay server', function() {
   describe('#createWallet', function() {
     beforeEach(function() {
       server = new CopayServer({
-        db: db,
+        storage: storage,
       });
     });
 
@@ -151,7 +154,7 @@ describe('Copay server', function() {
   describe('#joinWallet', function() {
     beforeEach(function() {
       server = new CopayServer({
-        db: db,
+        storage: storage,
       });
     });
 
@@ -324,7 +327,7 @@ describe('Copay server', function() {
   describe('#createAddress', function() {
     beforeEach(function() {
       server = new CopayServer({
-        db: db,
+        storage: storage,
       });
     });
 
@@ -345,7 +348,7 @@ describe('Copay server', function() {
   describe('#createTx', function() {
     beforeEach(function(done) {
       server = new CopayServer({
-        db: db,
+        storage: storage,
       });
       server._doCreateAddress = sinon.stub().returns(new Address({ address: 'addr1', path: 'path1' }));
       helpers.createAndJoinWallet('123', 2, 2, function (err, wallet) {