Why does jest testing of a vue component fail?

Question

Software testing

Hello, I have a component with a method:

scrollToParent() {
            const id = _get(this, 'comment.attributes.parent_id'); // lodash get
            const parentId = `#comment-${id}`;
            this.$emit('scrollToParent', parentId, id);
},

emit is listened to in parent component and test for it
<Tag ... @scrollToParent="scrollToParent" ... />

it('scrollToParent - Должен вызвать emit со свойством scrollToParent и payload', () => {
            component.vm.$emit = jest.fn();
            component.setProps({
                comment: {
                    attributes: {
                        parent_id: 3,
                    },
                },
            });
            component.vm.scrollToParent();
            expect(component.vm.$emit).toBeCalledWith('scrollToParent', '#comment-3', 3);
});

The test explicitly specifies parent_id by the setProps method, but for some reason the test ends up with parent_id being undefined. Why is this happening?