fix(fakeAsync): throw error on rejected promisees.

Author: mhevery

Diff for: lib/zone-spec/fake-async-test.ts

@@ -80,6 +80,7 @@
     private _scheduler: Scheduler = new Scheduler();
     private _microtasks: Function[] = [];
     private _lastError: Error = null;
+    private _uncaughtPromiseErrors: {rejection: any}[] = Promise[Zone['__symbol__']('uncaughtPromiseErrors')];
 
     pendingPeriodicTimers: number[] = [];
     pendingTimers: number[] = [];
@@ -172,7 +173,8 @@
     }
 
     private _resetLastErrorAndThrow(): void {
-      let error = this._lastError;
+      let error = this._lastError || this._uncaughtPromiseErrors[0];
+      this._uncaughtPromiseErrors.length = 0;
       this._lastError = null;
       throw error;
     }
@@ -188,14 +190,17 @@
 
     flushMicrotasks(): void {
       FakeAsyncTestZoneSpec.assertInZone();
-      while (this._microtasks.length > 0) {
-        let microtask = this._microtasks.shift();
-        microtask();
-        if (this._lastError !== null) {
+      const flushErrors = () => {
+        if (this._lastError !== null || this._uncaughtPromiseErrors.length) {
           // If there is an error stop processing the microtask queue and rethrow the error.
           this._resetLastErrorAndThrow();
         }
       }
+      while (this._microtasks.length > 0) {
+        let microtask = this._microtasks.shift();
+        microtask();
+      }
+      flushErrors();
     }
 
     // ZoneSpec implementation below.

Diff for: lib/zone.ts

@@ -868,7 +868,7 @@ const Zone: ZoneType = (function(global: any) {
   let _currentTask: Task = null;
   let _microTaskQueue: Task[] = [];
   let _isDrainingMicrotaskQueue: boolean = false;
-  let _uncaughtPromiseErrors: UncaughtPromiseError[] = [];
+  const _uncaughtPromiseErrors: UncaughtPromiseError[] = [];
   let _drainScheduled: boolean = false;
 
   function scheduleQueueDrain() {
@@ -894,7 +894,8 @@ const Zone: ZoneType = (function(global: any) {
           'Unhandled Promise rejection:', rejection instanceof Error ? rejection.message : rejection,
           '; Zone:', (<Zone>e.zone).name,
           '; Task:', e.task && (<Task>e.task).source,
-          '; Value:', rejection
+          '; Value:', rejection, 
+          rejection instanceof Error ? rejection.stack : undefined
       );
     }
     console.error(e);
@@ -916,10 +917,8 @@ const Zone: ZoneType = (function(global: any) {
         }
       }
       while(_uncaughtPromiseErrors.length) {
-        const uncaughtPromiseErrors = _uncaughtPromiseErrors;
-        _uncaughtPromiseErrors = [];
-        for (let i = 0; i < uncaughtPromiseErrors.length; i++) {
-          const uncaughtPromiseError: UncaughtPromiseError = uncaughtPromiseErrors[i];
+        while(_uncaughtPromiseErrors.length) {
+          const uncaughtPromiseError: UncaughtPromiseError = _uncaughtPromiseErrors.shift();
           try {
             uncaughtPromiseError.zone.runGuarded(() => { throw uncaughtPromiseError; });
           } catch (e) {
@@ -1119,5 +1118,7 @@ const Zone: ZoneType = (function(global: any) {
     }
   }
 
+  // This is not part of public API, but it is usefull for tests, so we expose it.
+  Promise[Zone.__symbol__('uncaughtPromiseErrors')] = _uncaughtPromiseErrors;
   return global.Zone = Zone;
 })(typeof window === 'undefined' ? global : window);

Diff for: test/zone-spec/fake-async-test.spec.ts

@@ -30,6 +30,15 @@ describe('FakeAsyncTestZoneSpec', () => {
         fakeAsyncTestZone.run(() => { throw new Error('sync'); });
       }).toThrowError('sync');
     });
+
+    it('should throw error on Rejected promise', () => {
+      expect(() => {
+        fakeAsyncTestZone.run(() => { 
+          Promise.reject('myError')
+          testZoneSpec.flushMicrotasks(); 
+        });
+      }).toThrowError('Uncaught (in promise): myError');
+    });
   });
 
   describe('asynchronous code', () => {