Simple React Button Unit Test

Button.test.jsx

import { mount } from 'enzyme';
import * as React from 'react';
import { Button } from './button';

describe('<Button />', () => {
  describe('By default', () => {
    let component;
    beforeAll(() => {
      component = mount(<Button label="foo" />);
    });
    
    it('renders with a primary flavour', () => {
      expect(component.html()).toMatchSnapshot();
    });
    it('does nothing on clicks', () => {
      let clickEvent = () => {
        component.find('button').simulate('click');
      };
      expect(clickEvent).not.toThrow();
    });
  });
  describe('Using props', () => {
    let component;
    let clickFn = jest.fn();
    beforeAll(() => {
      component = mount(<Button label="foo" flavour="bar" onClick={clickFn} />);
    });
    it('renders with the passed flavour', () => {
      expect(component.html()).toMatchSnapshot();
    });
    it('calls the onClick prop function when clicked', () => {
      expect(clickFn).not.toHaveBeenCalled();
      component.find('button').simulate('click');
      expect(clickFn).toHaveBeenCalled();
    });
  });
}