How to mock e.preventDefault in react component's child

Question

Hy, I don't know how to mock an inline function in React component's child

My stack: sinon, chai, enzyme;

Component usage:

<ListItem onClick={() => someFn()} />

Component's render:

render() {
    return (
      <li>
        <a href="#" onClick={e => {
            e.preventDefault();
            this.props.onClick();
          }}
        > whatever </a>
      </li>
    );
  }

Here we have onClick function that calls e.preventDefault(). How to tell to <a href>(link) to not to call e.preventDefault()? How can I mock an onClick?

Below is what I have tried in tests:

Shallow copy setup

function setup() {
  const someFn = sinon.stub();

  const component = shallow(
    <ListItem
      onClick={() => {
        someFn();
      }}
    />
  );

  return {
    component: component,
    actions: someFn,
    link: component.find('a'),
    listItem: component.find('li'),
  }
}

And the test

  it('simulates click events', () => {
    const { link, actions } = setup();
    link.simulate('click'); //Click on <a href>
    expect(actions).to.have.property('callCount', 1); //will be fine if we remove e.preventDefault()
  });

Test's output error:

TypeError: Cannot read property 'preventDefault' of undefined

Answer 1

Try this

link.simulate('click', {
  preventDefault: () => {
  }
 });