js__react_enzyme__egghead/src/App.test.js

import "raf/polyfill";
import React from "react";
import App from "./App";
import { configure, shallow } from "enzyme";
import Adapter from "enzyme-adapter-react-16";

// Configure Enzyme for the React version we are using.
// Could be in a test setup file. Required for React 16, 15, 0.14, 0.13.
configure({ adapter: new Adapter() });

describe("<App />>", () => {
  const wrapper = shallow(<App />);

  it("should contain 1 p element", () => {
    // There is one <p> in <App />: only one shoud be present in shallow rendering.
    expect(wrapper.find("p").length).toBe(1);

    expect(wrapper.find("p.App-intro").exists()).toBe(true);

    expect(wrapper.find("ul").hasClass("tyler")).toBe(true);

    expect(wrapper.find("ul").children().length).toBe(3);

    expect(wrapper.find("h1").text()).toBe("Welcome to React");
  });
});