Jest not implemented for window.open, getting error on the console but unit test is getting pass with console error a.ts file myFun(){ window.open('https://stackoverflow.com/', '_blank'); } a.spec.ts providers: [ { useValue: { open: jest.fn() } } ] ---------------------------------------------- it('should open window on submit ', () => { const spy = spyOn(window, 'open').and.callFake(() => {}); component.submit(); expect(spy).toHaveBeenCalledWith('https://stackoverflow.com/', '_blank'); }); Console error `console.error node_modules/jsdom/lib/jsdom/virtual-console.js:29 Error: Not implemented: window.open at module.exports (C:\workspace\guide-ast\fis-my-support\node_modules\jsdom\lib\jsdom\browser\not-implemented.js:9:17) at C:\workspace\guide-ast\fis-my-support\node_modules\jsdom\lib\jsdom\browser\Window.js:594:7 at SafeSubscriber._next (C:\workspace\guide-ast\fis-my-support\apps\ui\src\app\ticket-creation\formly-ticket-page\formly-ticket-page.component.ts:167:18) at SafeSubscriber.Object.<anonymous>.SafeSubscriber.__tryOrUnsub (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\Subscriber.ts:265:10) at SafeSubscriber.Object.<anonymous>.SafeSubscriber.next (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\Subscriber.ts:207:14) at Subscriber.Object.<anonymous>.Subscriber._next (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\Subscriber.ts:139:22) at Subscriber.Object.<anonymous>.Subscriber.next (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\Subscriber.ts:99:12) at TakeWhileSubscriber.Object.<anonymous>.TakeWhileSubscriber.nextOrComplete (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\operators\takeWhile.ts:102:19) at TakeWhileSubscriber.Object.<anonymous>.TakeWhileSubscriber._next (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\operators\takeWhile.ts:96:10) at TakeWhileSubscriber.Object.<anonymous>.Subscriber.next (C:\workspace\guide-ast\fis-my-support\node_modules\rxjs\src\internal\Subscriber.ts:99:12) undefined` Continue reading...