diff --git a/modules/angular2/src/testing/test_injector.ts b/modules/angular2/src/testing/test_injector.ts
index c5e23a6a0b..21bef44e65 100644
--- a/modules/angular2/src/testing/test_injector.ts
+++ b/modules/angular2/src/testing/test_injector.ts
@@ -123,7 +123,9 @@ export function createTestInjector(providers: Array<Type | Provider | any[]>): I
 }
 
 /**
- * Allows injecting dependencies in `beforeEach()` and `it()`.
+ * Allows injecting dependencies in `beforeEach()` and `it()`. When using with the
+ * `angular2/testing` library, the test function will be run within a zone and will
+ * automatically complete when all asynchronous tests have finished.
  *
  * Example:
  *
@@ -133,17 +135,14 @@ export function createTestInjector(providers: Array<Type | Provider | any[]>): I
  *   // ...
  * }));
  *
- * it('...', inject([AClass, AsyncTestCompleter], (object, async) => {
+ * it('...', inject([AClass], (object) => {
  *   object.doSomething().then(() => {
  *     expect(...);
- *     async.done();
  *   });
  * })
  * ```
  *
  * Notes:
- * - injecting an `AsyncTestCompleter` allow completing async tests - this is the equivalent of
- *   adding a `done` parameter in Jasmine,
  * - inject is currently a function because of some Traceur limitation the syntax should eventually
  *   becomes `it('...', @Inject (object: AClass, async: AsyncTestCompleter) => { ... });`
  *
@@ -155,6 +154,9 @@ export function inject(tokens: any[], fn: Function): FunctionWithParamTokens {
   return new FunctionWithParamTokens(tokens, fn, false);
 }
 
+/**
+ * @deprecated Use inject instead, which now supports both synchronous and asynchronous tests.
+ */
 export function injectAsync(tokens: any[], fn: Function): FunctionWithParamTokens {
   return new FunctionWithParamTokens(tokens, fn, true);
 }
diff --git a/modules/angular2/src/testing/testing.ts b/modules/angular2/src/testing/testing.ts
index 3aa571bf88..f6cacfb5f1 100644
--- a/modules/angular2/src/testing/testing.ts
+++ b/modules/angular2/src/testing/testing.ts
@@ -3,7 +3,7 @@
  * Jasmine framework.
  */
 import {global} from 'angular2/src/facade/lang';
-
+import {ListWrapper} from 'angular2/src/facade/collection';
 import {bind} from 'angular2/src/core/di';
 
 import {createTestInjector, FunctionWithParamTokens, inject, injectAsync} from './test_injector';
@@ -14,10 +14,29 @@ export {expect, NgMatchers} from './matchers';
 
 var _global: jasmine.GlobalPolluter = <any>(typeof window === 'undefined' ? global : window);
 
+/**
+ * See http://jasmine.github.io/
+ */
 export var afterEach: Function = _global.afterEach;
+
+/**
+ * See http://jasmine.github.io/
+ */
 export var describe: Function = _global.describe;
+
+/**
+ * See http://jasmine.github.io/
+ */
 export var ddescribe: Function = _global.fdescribe;
+
+/**
+ * See http://jasmine.github.io/
+ */
 export var fdescribe: Function = _global.fdescribe;
+
+/**
+ * See http://jasmine.github.io/
+ */
 export var xdescribe: Function = _global.xdescribe;
 
 export type SyncTestFn = () => void;
@@ -40,16 +59,18 @@ jsmBeforeEach(() => {
 
 /**
  * Allows overriding default providers of the test injector,
- * defined in test_injector.js.
+ * which are defined in test_injector.js.
  *
  * The given function must return a list of DI providers.
  *
  * Example:
  *
+ * ```
  *   beforeEachProviders(() => [
  *     bind(Compiler).toClass(MockCompiler),
  *     bind(SomeToken).toValue(myValue),
  *   ]);
+ * ```
  */
 export function beforeEachProviders(fn): void {
   jsmBeforeEach(() => {
@@ -68,72 +89,101 @@ function _isPromiseLike(input): boolean {
   return input && !!(input.then);
 }
 
+function runInTestZone(fnToExecute, finishCallback, failCallback): any {
+  var pendingMicrotasks = 0;
+  var pendingTimeouts = [];
+
+  var ngTestZone = (<Zone>global.zone)
+                       .fork({
+                         onError: function(e) { failCallback(e); },
+                         '$run': function(parentRun) {
+                           return function() {
+                             try {
+                               return parentRun.apply(this, arguments);
+                             } finally {
+                               if (pendingMicrotasks == 0 && pendingTimeouts.length == 0) {
+                                 finishCallback();
+                               }
+                             }
+                           };
+                         },
+                         '$scheduleMicrotask': function(parentScheduleMicrotask) {
+                           return function(fn) {
+                             pendingMicrotasks++;
+                             var microtask = function() {
+                               try {
+                                 fn();
+                               } finally {
+                                 pendingMicrotasks--;
+                               }
+                             };
+                             parentScheduleMicrotask.call(this, microtask);
+                           };
+                         },
+                         '$setTimeout': function(parentSetTimeout) {
+                           return function(fn: Function, delay: number, ...args) {
+                             var id;
+                             var cb = function() {
+                               fn();
+                               ListWrapper.remove(pendingTimeouts, id);
+                             };
+                             id = parentSetTimeout(cb, delay, args);
+                             pendingTimeouts.push(id);
+                             return id;
+                           };
+                         },
+                         '$clearTimeout': function(parentClearTimeout) {
+                           return function(id: number) {
+                             parentClearTimeout(id);
+                             ListWrapper.remove(pendingTimeouts, id);
+                           };
+                         },
+                       });
+
+  return ngTestZone.run(fnToExecute);
+}
+
 function _it(jsmFn: Function, name: string, testFn: FunctionWithParamTokens | AnyTestFn,
              testTimeOut: number): void {
   var timeOut = testTimeOut;
 
   if (testFn instanceof FunctionWithParamTokens) {
-    // The test case uses inject(). ie `it('test', inject([ClassA], (a) => { ...
-    // }));`
-    if (testFn.isAsync) {
-      jsmFn(name, (done) => {
-        if (!injector) {
-          injector = createTestInjector(testProviders);
-        }
-        var returned = testFn.execute(injector);
-        if (_isPromiseLike(returned)) {
-          returned.then(done, done.fail);
-        } else {
-          done.fail('Error: injectAsync was expected to return a promise, but the ' +
-                    ' returned value was: ' + returned);
-        }
-      }, timeOut);
-    } else {
-      jsmFn(name, () => {
-        if (!injector) {
-          injector = createTestInjector(testProviders);
-        }
-        var returned = testFn.execute(injector);
-        if (_isPromiseLike(returned)) {
-          throw new Error('inject returned a promise. Did you mean to use injectAsync?');
-        };
-      });
-    }
+    jsmFn(name, (done) => {
+      if (!injector) {
+        injector = createTestInjector(testProviders);
+      }
+
+      var returnedTestValue = runInTestZone(() => testFn.execute(injector), done, done.fail);
+      if (_isPromiseLike(returnedTestValue)) {
+        (<Promise<any>>returnedTestValue).then(null, (err) => { done.fail(err); });
+      }
+    }, timeOut);
   } else {
     // The test case doesn't use inject(). ie `it('test', (done) => { ... }));`
     jsmFn(name, testFn, timeOut);
   }
 }
 
-
+/**
+ * Wrapper around Jasmine beforeEach function.
+ * See http://jasmine.github.io/
+ *
+ * beforeEach may be used with the `inject` function to fetch dependencies.
+ * The test will automatically wait for any asynchronous calls inside the
+ * injected test function to complete.
+ */
 export function beforeEach(fn: FunctionWithParamTokens | AnyTestFn): void {
   if (fn instanceof FunctionWithParamTokens) {
     // The test case uses inject(). ie `beforeEach(inject([ClassA], (a) => { ...
     // }));`
-    if (fn.isAsync) {
-      jsmBeforeEach((done) => {
-        if (!injector) {
-          injector = createTestInjector(testProviders);
-        }
-        var returned = fn.execute(injector);
-        if (_isPromiseLike(returned)) {
-          returned.then(done, done.fail);
-        } else {
-          done.fail('Error: injectAsync was expected to return a promise, but the ' +
-                    ' returned value was: ' + returned);
-        }
-      });
-    } else {
-      jsmBeforeEach(() => {
-        if (!injector) {
-          injector = createTestInjector(testProviders);
-        }
-        var returned = fn.execute(injector);
-        if (_isPromiseLike(returned)) {
-          throw new Error('inject returned a promise. Did you mean to use injectAsync?');
-        };
-      });
-    }
+
+    jsmBeforeEach((done) => {
+      if (!injector) {
+        injector = createTestInjector(testProviders);
+      }
+
+      runInTestZone(() => fn.execute(injector), done, done.fail);
+    });
   } else {
     // The test case doesn't use inject(). ie `beforeEach((done) => { ... }));`
     if ((<any>fn).length === 0) {
@@ -144,21 +194,53 @@ export function beforeEach(fn: FunctionWithParamTokens | AnyTestFn): void {
   }
 }
 
+/**
+ * Wrapper around Jasmine it function.
+ * See http://jasmine.github.io/
+ *
+ * it may be used with the `inject` function to fetch dependencies.
+ * The test will automatically wait for any asynchronous calls inside the
+ * injected test function to complete.
+ */
 export function it(name: string, fn: FunctionWithParamTokens | AnyTestFn,
                    timeOut: number = null): void {
   return _it(jsmIt, name, fn, timeOut);
 }
 
+/**
+ * Wrapper around Jasmine xit (skipped it) function.
+ * See http://jasmine.github.io/
+ *
+ * it may be used with the `inject` function to fetch dependencies.
+ * The test will automatically wait for any asynchronous calls inside the
+ * injected test function to complete.
+ */
 export function xit(name: string, fn: FunctionWithParamTokens | AnyTestFn,
                     timeOut: number = null): void {
   return _it(jsmXIt, name, fn, timeOut);
 }
 
+/**
+ * Wrapper around Jasmine iit (focused it) function.
+ * See http://jasmine.github.io/
+ *
+ * it may be used with the `inject` function to fetch dependencies.
+ * The test will automatically wait for any asynchronous calls inside the
+ * injected test function to complete.
+ */
 export function iit(name: string, fn: FunctionWithParamTokens | AnyTestFn,
                     timeOut: number = null): void {
   return _it(jsmIIt, name, fn, timeOut);
 }
 
+/**
+ * Wrapper around Jasmine fit (focused it) function.
+ * See http://jasmine.github.io/
+ *
+ * it may be used with the `inject` function to fetch dependencies.
+ * The test will automatically wait for any asynchronous calls inside the
+ * injected test function to complete.
+ */
 export function fit(name: string, fn: FunctionWithParamTokens | AnyTestFn,
                     timeOut: number = null): void {
   return _it(jsmIIt, name, fn, timeOut);
diff --git a/modules/angular2/test/testing/testing_public_spec.ts b/modules/angular2/test/testing/testing_public_spec.ts
index 055d85611b..d02917009e 100644
--- a/modules/angular2/test/testing/testing_public_spec.ts
+++ b/modules/angular2/test/testing/testing_public_spec.ts
@@ -9,7 +9,6 @@ import {
   tick,
   beforeEach,
   inject,
-  injectAsync,
   beforeEachProviders,
   TestComponentBuilder
 } from 'angular2/testing';
@@ -17,6 +16,7 @@ import {
 import {Injectable, bind} from 'angular2/core';
 import {NgIf} from 'angular2/common';
 import {Directive, Component, View, ViewMetadata} from 'angular2/core';
+import {PromiseWrapper} from 'angular2/src/facade/promise';
 import {XHR} from 'angular2/src/compiler/xhr';
 import {XHRImpl} from 'angular2/src/platform/browser/xhr_impl';
 
@@ -153,9 +153,8 @@ export function main() {
       it('should use set up providers',
          inject([FancyService], (service) => { expect(service.value).toEqual('real value'); }));
 
-      it('should wait until returned promises', injectAsync([FancyService], (service) => {
-           return service.getAsyncValue().then(
-               (value) => { expect(value).toEqual('async value'); });
+      it('should wait until returned promises', inject([FancyService], (service) => {
+           service.getAsyncValue().then((value) => { expect(value).toEqual('async value'); });
          }));
 
       describe('using beforeEach', () => {
@@ -168,8 +167,8 @@ export function main() {
       });
 
       describe('using async beforeEach', () => {
-        beforeEach(injectAsync([FancyService], (service) => {
-          return service.getAsyncValue().then((value) => { service.value = value; });
+        beforeEach(inject([FancyService], (service) => {
+          service.getAsyncValue().then((value) => { service.value = value; });
         }));
 
         it('should use asynchronously modified value',
@@ -181,14 +180,17 @@ export function main() {
   describe('errors', () => {
     var originalJasmineIt: any;
     var originalJasmineBeforeEach: any;
+
     var patchJasmineIt = () => {
+      var deferred = PromiseWrapper.completer();
       originalJasmineIt = jasmine.getEnv().it;
       jasmine.getEnv().it = (description: string, fn) => {
-        var done = () => {};
-        (<any>done).fail = (err) => { throw new Error(err) };
+        var done = () => { deferred.resolve() };
+        (<any>done).fail = (err) => { deferred.reject(err) };
         fn(done);
         return null;
-      }
+      };
+      return deferred.promise;
     };
 
     var restoreJasmineIt = () => { jasmine.getEnv().it = originalJasmineIt; };
@@ -206,40 +208,46 @@ export function main() {
     var restoreJasmineBeforeEach =
         () => { jasmine.getEnv().beforeEach = originalJasmineBeforeEach; }
 
-    it('should fail when return was forgotten in it', () => {
-      expect(() => {
-        patchJasmineIt();
-        it('forgets to return a promise', injectAsync([], () => { return true; }));
-      })
-          .toThrowError('Error: injectAsync was expected to return a promise, but the ' +
-                        ' returned value was: true');
+    it('should fail when an error occurs inside inject', (done) => {
+      var itPromise = patchJasmineIt();
+      it('throws an error', inject([], () => { throw new Error('foo'); }));
+
+      itPromise.then(() => { done.fail('Expected function to throw, but it did not'); }, (err) => {
+        expect(err.message).toEqual('foo');
+        done();
+      });
       restoreJasmineIt();
     });
 
-    it('should fail when synchronous spec returns promise', () => {
-      expect(() => {
-        patchJasmineIt();
-        it('returns an extra promise', inject([], () => { return Promise.resolve('true'); }));
-      }).toThrowError('inject returned a promise. Did you mean to use injectAsync?');
+    it('should fail when an asynchronous error is thrown', (done) => {
+      var itPromise = patchJasmineIt();
+
+      it('throws an async error',
+         inject([], () => { setTimeout(() => { throw new Error('bar'); }, 0); }));
+
+      itPromise.then(() => { done.fail('Expected test to fail, but it did not'); }, (err) => {
+        expect(err.message).toEqual('bar');
+        done();
+      });
       restoreJasmineIt();
     });
 
-    it('should fail when return was forgotten in beforeEach', () => {
-      expect(() => {
-        patchJasmineBeforeEach();
-        beforeEach(injectAsync([], () => { return true; }));
-      })
-          .toThrowError('Error: injectAsync was expected to return a promise, but the ' +
-                        ' returned value was: true');
-      restoreJasmineBeforeEach();
-    });
+    it('should fail when a returned promise is rejected', (done) => {
+      var itPromise = patchJasmineIt();
 
-    it('should fail when synchronous beforeEach returns promise', () => {
-      expect(() => {
-        patchJasmineBeforeEach();
-        beforeEach(inject([], () => { return Promise.resolve('true'); }));
-      }).toThrowError('inject returned a promise. Did you mean to use injectAsync?');
-      restoreJasmineBeforeEach();
+      it('should fail with an error from a promise', inject([], () => {
+           var deferred = PromiseWrapper.completer();
+           var p = deferred.promise.then(() => { expect(1).toEqual(2); });
+
+           deferred.reject('baz');
+           return p;
+         }));
+
+      itPromise.then(() => { done.fail('Expected test to fail, but it did not'); }, (err) => {
+        expect(err).toEqual('baz');
+        done();
+      });
+      restoreJasmineIt();
     });
 
     describe('using beforeEachProviders', () => {
@@ -265,9 +273,9 @@ export function main() {
 
   describe('test component builder', function() {
     it('should instantiate a component with valid DOM',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+       inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.createAsync(ChildComp).then((componentFixture) => {
+         tcb.createAsync(ChildComp).then((componentFixture) => {
            componentFixture.detectChanges();
 
            expect(componentFixture.debugElement.nativeElement).toHaveText('Original Child');
@@ -275,9 +283,9 @@ export function main() {
        }));
 
     it('should allow changing members of the component',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+       inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.createAsync(MyIfComp).then((componentFixture) => {
+         tcb.createAsync(MyIfComp).then((componentFixture) => {
            componentFixture.detectChanges();
            expect(componentFixture.debugElement.nativeElement).toHaveText('MyIf()');
 
@@ -287,10 +295,9 @@ export function main() {
          });
        }));
 
-    it('should override a template',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+    it('should override a template', inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideTemplate(MockChildComp, '<span>Mock</span>')
+         tcb.overrideTemplate(MockChildComp, '<span>Mock</span>')
              .createAsync(MockChildComp)
              .then((componentFixture) => {
                componentFixture.detectChanges();
@@ -299,12 +306,10 @@ export function main() {
              });
        }));
 
-    it('should override a view',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+    it('should override a view', inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideView(
-                       ChildComp,
-                       new ViewMetadata({template: '<span>Modified {{childBinding}}</span>'}))
+         tcb.overrideView(ChildComp,
+                          new ViewMetadata({template: '<span>Modified {{childBinding}}</span>'}))
              .createAsync(ChildComp)
              .then((componentFixture) => {
                componentFixture.detectChanges();
@@ -314,9 +319,9 @@ export function main() {
        }));
 
     it('should override component dependencies',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+       inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideDirective(ParentComp, ChildComp, MockChildComp)
+         tcb.overrideDirective(ParentComp, ChildComp, MockChildComp)
              .createAsync(ParentComp)
              .then((componentFixture) => {
                componentFixture.detectChanges();
@@ -327,9 +332,9 @@ export function main() {
 
 
     it("should override child component's dependencies",
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+       inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideDirective(ParentComp, ChildComp, ChildWithChildComp)
+         tcb.overrideDirective(ParentComp, ChildComp, ChildWithChildComp)
              .overrideDirective(ChildWithChildComp, ChildChildComp, MockChildChildComp)
              .createAsync(ParentComp)
              .then((componentFixture) => {
@@ -340,11 +345,9 @@ export function main() {
              });
        }));
 
-    it('should override a provider',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+    it('should override a provider', inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideProviders(TestProvidersComp,
-                                      [bind(FancyService).toClass(MockFancyService)])
+         tcb.overrideProviders(TestProvidersComp, [bind(FancyService).toClass(MockFancyService)])
              .createAsync(TestProvidersComp)
              .then((componentFixture) => {
                componentFixture.detectChanges();
@@ -355,10 +358,10 @@ export function main() {
 
 
     it('should override a viewProvider',
-       injectAsync([TestComponentBuilder], (tcb: TestComponentBuilder) => {
+       inject([TestComponentBuilder], (tcb: TestComponentBuilder) => {
 
-         return tcb.overrideViewProviders(TestViewProvidersComp,
-                                          [bind(FancyService).toClass(MockFancyService)])
+         tcb.overrideViewProviders(TestViewProvidersComp,
+                                   [bind(FancyService).toClass(MockFancyService)])
              .createAsync(TestViewProvidersComp)
              .then((componentFixture) => {
                componentFixture.detectChanges();