const WrapperComponent = { components: { ChildComponent, }, methods: { onUpdate: jest.fn(), }, template: '<child-component @onUpdate="onUpdate" />', }; describe('ChildComponent', () => { let wrapper; beforeEach(() => { wrapper = mount(WrapperComponent, {}); }); afterEach(() => { wrapper.destroy(); }); it('emits onUpdate event', async () => { const spy = jest.spyOn(WrapperComponent.methods, 'onUpdate'); // do something that would make child component emit the 'onUpdate' event expect(spy).toHaveBeenCalled(); }); });