Fix race condition where MyEmail model was not attached to the correct dataSource in tests

lib/connectors/mail.js

@@ -22,7 +22,7 @@ function MailConnector(settings) {
   var transports = settings.transports || [];
   this.transportsIndex = {};
   this.transports = [];
-
+  
   transports.forEach(this.setupTransport.bind(this));
 }
 
@@ -83,10 +83,9 @@ MailConnector.prototype.transportForName = function(name) {
  */
 
 MailConnector.prototype.defaultTransport = function() {
-  return this.transports[0];
+  return this.transports[0] || this.stubTransport;
 }
 
-
 /**
  * Send an email with the given `options`.
  *
@@ -110,6 +109,8 @@ Mailer.send = function (options, fn) {
   var dataSource = this.dataSource;
   var settings = dataSource && dataSource.settings;
   var connector = dataSource.connector;
+  assert(connector, 'Cannot send mail without a connector!');
+
   var transport = connector.transportForName(options.transport);
 
   if(!transport) {

test/email.test.js

@@ -1,9 +1,13 @@
 var loopback = require('../');
-var MyEmail = loopback.Email.extend('my-email');
+var MyEmail;
 var assert = require('assert');
 
 describe('Email and SMTP', function () {
-
+  beforeEach(function() {
+    MyEmail = loopback.Email.extend('my-email');
+    loopback.autoAttach();
+  });
+  
   it('should have a send method', function () {
     assert(typeof MyEmail.send === 'function');
     assert(typeof MyEmail.prototype.send === 'function');