feat(jasmine): support Date.now in fakeAsyncTest

[JiaLiPassion]

fix angular/angular#8678

support Date.now in fakeAsyncTest. there are 3 features in this PR.

• support auto patch Date.now and new Date() in fakeAsync.

 fakeAsyncTestZone.run(() => {
        const start = Date.now();
        testZoneSpec.tick(100);
        const end = Date.now();
        expect(end - start).toBe(100);
  });

 fakeAsyncTestZone.run(() => {
        const start = new Date();
        testZoneSpec.tick(100);
        const end = new Date();
        expect(end.getTime() - start.getTime()).toBe(100);
  });

• automatically run a fakeAsync test when jasmine.clock().install is called.

beforeEach(() => {
      jasmine.clock().install();
    });

    afterEach(() => {
      jasmine.clock().uninstall();
    });

    it('should get date diff correctly', () => {  // we don't need fakeAsync here.
      // automatically run into fake async zone, because jasmine.clock() is installed.
      const start = Date.now();
      jasmine.clock().tick(100);
      const end = Date.now();
      expect(end - start).toBe(100);
    });

• rxjs Scheduler support, need to import zone.js/dist/zone-patch-rxjs-fake-async.

    import '../../lib/rxjs/rxjs-fake-async';
    it('should get date diff correctly', (done) => {
      fakeAsyncTestZone.run(() => {
        let result = null;
        const observable = new Observable((subscribe: any) => {
          subscribe.next('hello');
        });
        observable.delay(1000).subscribe(v => {
          result = v;
        });
        expect(result).toBeNull();
        testZoneSpec.tick(1000);
        expect(result).toBe('hello');
        done();
      });
    });

@mhevery , @vikerman , please review, thank you!

[Jopie64]

@JiaLiPassion
For your info, your last test leaks a subscription.
Instead of this:

const observable = new Observable((subscribe: any) => {
  subscribe.next('hello');
});
observable.delay(1000).subscribe(v => {
  result = v;
});

You can write this to fix it:

Observable.of('hello').delay(1000).subscribe(v => result = v);

(Observable.of() completes after sending the single value)

Anyway, thanks for making my library obsolete! 👍 XD

[JiaLiPassion]

@Jopie64 , thank you for the comment.

I didn't use Observable.of() because there is a bug in another patch zone-patch-rxjs. I have updated the test case to complete subscriber.

[alfaproject]

I couldn't make this work, so I'm a bit confused. angular-testing-ext npm package works out of the box as expected, and I was hoping to replace it. ):

[JiaLiPassion]

@alfaproject , with angular/angular#23108 merged, it should work, current angular not using newest version of zone.js.

[alfaproject]

But can't I use the latest version of zone.js with Angular 5? If not, I guess I'll have to wait then. ):

[JiaLiPassion]

@alfaproject , you can use latest version of zone.js (0.8.25) and old version of angular5. But you need a little setup. You need to import async, fakeAsync from zone instead of from angular/core/testing.

declare let Zone: any;
const async = Zone[Zone.__symbol__('asyncTest')];
const { fakeAsync, tick, flush, flushMicrotasks, discardPeriodicTasks, resetFakeAsyncZone } = Zone[Zone.__symbol__('fakeAsyncTest')];

and if you use jasmine.clock() feature, you need to add a flag before loading zone-testing in src/test.ts.

(window as any)['__zone_symbol__fakeAsyncPatchLock'] = true;
import 'zone.js/dist/zone-testing';

if you use rxjs.delay/scheduler, you need to

import 'zone.js/dist/zone-patch-rxjs-fake-async';

Could you try this in your project to see everything work fine or not? thank you!

[alfaproject]

@JiaLiPassion that works, thank you for helping!

[insidewhy]

Tried this out but my tests are still broken as clock.mockDate(new Date(...)); has no effect now.

[insidewhy]

Okay so clock.mockDate(new Date(...)); does work but only if used inside of your it, not when called in the beforeEach along with jasmine.clock().install() (before or after). Inconvenient when you have many tests grouped in a describe that should all be using the same mocked date.

[nschipperbrainsmith]

@JiaLiPassion Thanks for that, it's finally working though a note: I figured out the hard way that you have to import the delay operator above your snipped for this to function properly in angular 5:

import { Observable } from "rxjs/Observable";
import "rxjs/add/operator/delay";

declare let Zone: any;
const async = Zone[Zone.__symbol__("asyncTest")];
const {fakeAsync, tick, flush, flushMicrotasks, discardPeriodicTasks, resetFakeAsyncZone} = Zone[Zone.__symbol__(
	"fakeAsyncTest")];

import 'zone.js/dist/zone-patch-rxjs-fake-async';

[vicneanschi]

Thanks @JiaLiPassion!

[afeinber]

@JiaLiPassion Where are we supposed to get fakeAsyncTestZone from to call fakeAsyncTestZone.run?

[JiaLiPassion]

@afeinber, do you mean you want to get FakeAsyncTestZone or FakeASyncTestZoneSpec instance inside a fakeAsyncTestZone? You can get them like this.

const fakeAsyncTestZone = Zone.current.fork(Zone['FakeAsyncTestZoneSpec']);
fakeAsyncTestZone.run(() => {
  setTimeout(() => {
     const zone = Zone.current; // this will be === fakeAsyncTestZone;
     const fakeAsyncTestZoneSpec = Zone.current.get('FakeAsyncTestZoneSpec');
  });
});