fix(transaction): reject transaction promise when transaction callback does not …

…result in a promise chain

lib/sequelize.js

@@ -962,7 +962,10 @@ module.exports = (function() {
       deprecated('Note: When passing a callback to a transaction a promise chain is expected in return, the transaction will be committed or rejected based on the promise chain returned to the callback.');
       return new Promise(function (resolve, reject) {
         transaction.prepareEnvironment().then(function () {
-          autoCallback(transaction).then(function (result) {
+          var result = autoCallback(transaction);
+          if (!result) return reject(new Error('You need to return a promise chain to the sequelize.transaction() callback'));
+
+          result.then(function (result) {
             return transaction.commit().then(function () {
               resolve(result);
             });

test/support.js

@@ -5,7 +5,11 @@ var fs        = require('fs')
   , _         = require('lodash')
   , Sequelize = require(__dirname + "/../index")
   , DataTypes = require(__dirname + "/../lib/data-types")
-  , Config    = require(__dirname + "/config/config");
+  , Config    = require(__dirname + "/config/config")
+  , chai = require("chai")
+  , chaiAsPromised = require("chai-as-promised");
+
+chai.use(chaiAsPromised);
 
 // Make sure errors get thrown when testing
 Sequelize.Promise.onPossiblyUnhandledRejection(function(e, promise) {

test/transaction.test.js

@@ -42,18 +42,19 @@ describe(Support.getTestDialectTeaser("Transaction"), function () {
       });
     });
     it('supports automatically rolling back with a thrown error', function () {
-      return this.sequelize.transaction(function (t) {
+      return expect(this.sequelize.transaction(function (t) {
         throw new Error('Yolo');
-      }).catch(function (err) {
-        expect(err).to.be.ok;
-      });
+      })).to.eventually.be.rejected;
     });
     it('supports automatically rolling back with a rejection', function () {
-      return this.sequelize.transaction(function (t) {
+      return expect(this.sequelize.transaction(function (t) {
         return Promise.reject('Swag');
-      }).catch(function (err) {
-        expect(err).to.be.ok;
-      });
+      })).to.eventually.be.rejected;
+    });
+    it('errors when no promise chain is returned', function () {
+      return expect(this.sequelize.transaction(function (t) {
+        
+      })).to.eventually.be.rejected;
     });
   });