Using enzyme to test react components

HeaderComponent.js

// Header component to test in header.js
import React, {Component} from 'react';
import { Link } from 'react-router';

export class Header extends Component {

  render() {
    const { logoutUser } = this.props;
    
    return (
      <nav className="navbar navbar-light">
        <Link className='navbar-brand' to="/">PinPointMe</Link>
        <ul className='nav navbar-nav'>
          <li className='nav-item pull-right'>
            <a href="#" className='nav-link' onClick={ logoutUser }>Sign out</a>
          </li>
        </ul>
      </nav>
    );
  }
}

// Unit tests for header component in header.spec.js
import React from 'react';
import expect, { createSpy } from 'expect';
import { shallow } from 'enzyme';
import { Header } from './header';
import { Link } from 'react-router';

describe('Header', () => {
  
  it('Should have nav items of home, nav, and sign out', () => {
    const wrapper = shallow(<Header isAuth={ true } />); // Shallow rendering of header component
    expect(wrapper.containsMatchingElement(<Link to="/">PinPointMe</Link>)).toBe(true);
    expect(wrapper.find('nav').length).toEqual(1); // Can find nodes within the component
    expect(wrapper.find('.nav-link').html().includes('Sign out')).toBe(true); // Can find classnames
  });
  
  it('Should handle logout', () => {
    const spy = createSpy(); // Create a spy using the expect library
    const wrapper = shallow(<Header logoutUser={spy}/>);
    wrapper.find('a').simulate('click');
    expect(spy).toHaveBeenCalled();
  });
});