In our ionic unit test we are migrate our existing unit test to spectator unit test.

What we are doing here is we initialise our unit test with beforeEach.

beforeEach(async() => {
    spectator = createComponent()
    generalConfigService = TestBed.inject(GeneralConfigService)
    spyOn(spectator.component.generalService, 'getGeneralConfigState').and.returnValue(of(configDataMock))
    spectator.component.chartElement = chartViewInputMock.chartElement
    spectator.component.chartElementID = "0123456789"
    spectator.component.localstorageservice.setStoragedata('WXcurrentLevelInfo', { "level": "plant", "id": "64291", "timezone": { "abbr": "UTC", "offset": 0, "name": "UTC" } })
    spectator.component.localstorageservice.setStoragedata('PlantID', "64291")
    spectator.component.localstorageservice.setStoragedata('appConfigData', loginSuccessMock.appConfigData)
    await spectator.component.ngOnInit();
})

After this we try to run one case.

it('user can able to duplicate element if dashboard limit not excced',(async(done) => {
    let spy = spyOn(spectator.component.commonService,'alertMessage')
    popoverSpy.onDidDismiss.and.returnValue(Promise.resolve({data:'chartDuplicate'}));
    spectator.component.chartPopover('') // once execution of this function done than only I have to called next lines
    await spectator.fixture.whenStable() /// Never resolve so got error of timeout in unittest
    expect(popoverSpy.present).toHaveBeenCalled();
    expect(alertSpy.present).toHaveBeenCalled()
    done()
}))

So actual issue is spectator.fixture.whenStable() is some times worked correctly but generally it not resolved.So what we are writing after that line never executes and provide error like

Error: Timeout - Async function did not complete within 5000ms (set by jasmine.DEFAULT_TIMEOUT_INTERVAL)