Header-test.js

import "../../../../scripts/test-setup.js"

import React from "react";
import renderer from "react-test-renderer";
import sinon from "sinon";

import {shallow} from "enzyme";
import { BrowserRouter as Router } from "react-router-dom";

import Header from "../";

it("renders Header default correctly", () => {
  const tree = renderer.create(
    <Router><Header /></Router>
  ).toJSON();
  expect(tree).toMatchSnapshot();
});

it('Header click button', () => {
  const onClick = sinon.spy();
  const wrapper = shallow(<Header onClick={onClick} />);
  wrapper.find('button').simulate('click');
  expect(onClick.calledOnce).toEqual(true);
});