How to spy componentWillMount using jest and enzyme

Question

I am trying to test whether componentWillMount was called and for that my test is

test(\'calls `componentWillMount` before rendering\', () => {
  let fn =         


        

Answer 1

I would first spy on the component's componentWillMount method but also use .and.CallThrough() to prevent it from mocking its contents. Hope this helps:

it('should check that the componentWillMount method is getting called', () => {
    spyOn(SomeComponent.prototype, 'componentWillMount').and.callThrough();

    const wrapper = mount();

    expect(wrapper).toBeDefined();
    expect(SomeComponent.prototype.componentWillMount).toHaveBeenCalledTimes(1);
});