import PropTypes from 'prop-types';
import sinon from 'sinon';

const spy = sinon.spy();

class Foo extends React.Component {
  constructor(props) {
    super(props);
    this.componentWillUnmount = spy;
  }

  render() {
    const { id } = this.props;
    return (
      <div className={id}>
        {id}
      </div>
    );
  }
}
Foo.propTypes = {
  id: PropTypes.string.isRequired,
};
const wrapper = shallow(<Foo id="foo" />);
expect(spy).to.have.property('callCount', 0);
wrapper.unmount();
expect(spy).to.have.property('callCount', 1);