Implement .spread in custom event emitter

lib/emitters/custom-event-emitter.js

@@ -147,6 +147,19 @@ module.exports = (function() {
     }).then(onFulfilled, onRejected)
   }
 
+  CustomEventEmitter.prototype.spread = function(onFulfilled, onRejected) {
+    var self = this
+
+    onFulfilled = bindToProcess(onFulfilled)
+    onRejected = bindToProcess(onRejected)
+
+    return new Promise(function (resolve, reject) {
+      self.on('error', reject)
+          .on('success', function () {
+            resolve(Array.prototype.slice.apply(arguments)) // Transform args to an array
+          });
+    }).spread(onFulfilled, onRejected)
+  }
 
   return CustomEventEmitter;
 })()

test/promise.test.js

@@ -309,4 +309,52 @@ describe(Support.getTestDialectTeaser("Promise"), function () {
       })
     })
   })
+
+  describe('findOrCreate', function () {
+    beforeEach(function(done) {
+      this.User.create({ id: 1, aNumber: 0, bNumber: 0 }).done(done)
+    })
+
+    it('with then', function (done) {
+      this.User
+        .findOrCreate({ id: 1})
+        .then(function(user) {
+          expect(user.id).to.equal(1)
+          expect(arguments.length).to.equal(1)
+          done();
+        })      
+    })
+
+    describe('with spread', function () {
+      it('user not created', function (done) {
+        this.User
+          .findOrCreate({ id: 1})
+          .spread(function(user, created) {
+            expect(user.id).to.equal(1)
+            expect(created).to.equal(false)
+            expect(arguments.length).to.equal(2)
+            done();
+          })      
+      })
+      it('user created', function (done) {
+        this.User
+          .findOrCreate({ id: 2})
+          .spread(function(user, created) {
+            expect(user.id).to.equal(2)
+            expect(created).to.equal(true)
+            expect(arguments.length).to.equal(2)
+            done();
+          })      
+      })
+      it('works for functions with only one return value', function (done) {
+        this.User
+          .find({ id: 1})
+          .spread(function(user) {
+            expect(user.id).to.equal(1)
+            expect(arguments.length).to.equal(1)
+            done();
+          })    
+      })
+    })    
+  })
 })