Test-Driven React

How to Read the Code Examples

This book takes a hands-on, project-driven approach, which means that source files often change over the course of a chapter. When a code example is a work in progress, its file name (relative to the project root) is shown as a comment at the top of the snippet:

// src/tests/MyComponent.test.js
import React from 'react';
import MyComponent from '../MyComponent';

describe('MyComponent', () => {
  it('renders a <div /> tag', () => {
    const wrapper = shallow(<MyComponent />);
    expect(wrapper.type()).toBe('div');
  });
});

As a source file changes over the course of a chapter, familiar sections are omitted with ... and new/edited lines are highlighted:

// src/tests/MyComponent.test.js ...