Jest - when using spyOn function ensure the spied one is not called

From Jest notes: Note: By default, jest.spyOn also calls the spied method.

In my Angular component.

ngAfterViewInit(): void {
this.offsetPopoverPosition();
}


In my spec:

it('ngAfterViewInit() method should call offsetPopoverPosition() method', () => {
const mockListener = jest.spyOn(cmp, 'offsetPopoverPosition');
const spy = mockListener.mockImplementation(() => {
console.log('in the mock');
});

cmp.ngAfterViewInit();
expect(spy).toHaveBeenCalled();
});


Simple. Yet the original function is still being called. I checked Jest 23.x docs: https://jestjs.io/docs/en/23.x/jest-object#jestspyonobject-methodname https://jestjs.io/docs/en/23.x/mock-function-api#mockfnmockimplementationfn

And few examples on the internets but I can't prevent jest from calling the original offsetPopoverPosition() method.

Any ideas?

I am cross linking to Jest github issue which is for some reason closed without resolving it.

Jest spyOn() calls the actual function instead of the mocked

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