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Mock rxjs 5 Observable.timer for Angular unit tests with Jasmine
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| export function setFakeTimer(maxFrames?: number): TestScheduler { | |
| const originalTimer = Observable.timer; | |
| const scheduler = new TestScheduler((a, b) => expect(a).toEqual(b)); | |
| if (maxFrames) { | |
| scheduler.maxFrames = maxFrames; | |
| } | |
| spyOn(Observable, 'timer').and.callFake((initialDelay: number, dueTime: number) => { | |
| return originalTimer.call(this, initialDelay, dueTime, scheduler); | |
| }); | |
| return scheduler; | |
| } | |
| // Sample code under test, to increment counter every second | |
| let counter = 0; | |
| Observable.timer(0, 1000).do(() => { | |
| counter++; | |
| }).take(3).subscribe(); | |
| // Sample test | |
| it('should increment the counter every second', async(() => { | |
| setFakeTimer(5000); | |
| scheduler.schedule(() => { | |
| expect(counter).toBe(1); | |
| }, 0, null); | |
| scheduler.schedule(() => { | |
| expect(counter).toBe(2); | |
| }, 1000, null); | |
| scheduler.schedule(() => { | |
| expect(counter).toBe(3); | |
| }, 2000, null); | |
| scheduler.flush(); | |
| })); |
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