fakeAsync

function

npm Package	@angular/core
Module	import { fakeAsync } from '@angular/core/testing';
Source	core/testing/src/fake_async.ts

function fakeAsync(fn: Function): (...args: any[]) => any;

Description

Wraps a function to be executed in the fakeAsync zone:

• microtasks are manually executed by calling flushMicrotasks(),
• timers are synchronous, tick() simulates the asynchronous passage of time.

If there are any pending timers at the end of the function, an exception will be thrown.

Can be used to wrap inject() calls.

Example

describe('this test', () => {
  it('looks async but is synchronous', <any>fakeAsync((): void => {
       let flag = false;
       setTimeout(() => { flag = true; }, 100);
       expect(flag).toBe(false);
       tick(50);
       expect(flag).toBe(false);
       tick(50);
       expect(flag).toBe(true);
     }));
});