Just like with utility modules, creating tests for React components starts with creating the __tests__ directory. Navigate to ~/snapterest/source/components/ and create the __tests__ directory.
The first React component that we'll test will be our Header component. Create Header-test.js in the ~/snapterest/source/components/__tests__ directory:
jest.dontMock('../Header.react');
describe('Header component', function () {
it('renders provided header text', function () {
var React = require('react');
var ReactDOM = require('react-dom');
var TestUtils = require('react-addons-test-utils');
var Header = require('../Header.react');
var header = TestUtils.renderIntoDocument(
<Header text="Testing..." />
);
var actualHeaderText = ReactDOM.findDOMNode(header).textContent;
expect(actualHeaderText).toBe('Testing...');
var defaultHeader = TestUtils.renderIntoDocument(
<Header />
);
var actualDefaultHeaderText...