text: import React from 'react';
  import { shallow } from 'enzyme';
  import { Header } from '../../components/Header';
  
  test('should render Header correctly', () => {
    const wrapper = shallow(<Header onLogout={() => { }} />);
    expect(wrapper).toMatchSnapshot();
  });
  
  test('should call onLogout on button click', () => {
    const onLogoutSpy = jest.fn();
    const wrapper = shallow(<Header onLogout={onLogoutSpy} />);
    wrapper.find('button').simulate('click');
    expect(onLogoutSpy).toHaveBeenCalled();
  });
  