fix(fakeAsyncTest): fix #1061, fakeAsync should support setImmediate (#1062)

Closes #1062

Author: JiaLiPassion

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

@@ -425,6 +425,10 @@
                   task.invoke, task.data['delay'],
                   Array.prototype.slice.call((task.data as any)['args'], 2));
               break;
+            case 'setImmediate':
+              task.data['handleId'] = this._setTimeout(
+                  task.invoke, 0, Array.prototype.slice.call((task.data as any)['args'], 1));
+              break;
             case 'setInterval':
               task.data['handleId'] = this._setInterval(
                   task.invoke, task.data['delay'],

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

@@ -136,6 +136,20 @@ describe('FakeAsyncTestZoneSpec', () => {
       });
     });
 
+    it('should run queued immediate timer on zero tick', () => {
+      fakeAsyncTestZone.run(() => {
+        let ran = false;
+        setImmediate(() => {
+          ran = true;
+        });
+
+        expect(ran).toEqual(false);
+
+        testZoneSpec.tick();
+        expect(ran).toEqual(true);
+      });
+    });
+
     it('should run queued timer after sufficient clock ticks', () => {
       fakeAsyncTestZone.run(() => {
         let ran = false;
@@ -218,6 +232,18 @@ describe('FakeAsyncTestZoneSpec', () => {
       });
     });
 
+    it('should pass arguments to setImmediate', () => {
+      fakeAsyncTestZone.run(() => {
+        let value = 'genuine value';
+        let id = setImmediate((arg1, arg2) => {
+          value = arg1 + arg2;
+        }, 'expected', ' value');
+
+        testZoneSpec.tick();
+        expect(value).toEqual('expected value');
+      });
+    });
+
     it('should run periodic timers', () => {
       fakeAsyncTestZone.run(() => {
         let cycles = 0;