Mastering React Test-Driven Development

Submitting a form with data

The next test introduces some new concepts, so we'll break it down into its component parts. To start, add ReactTestUtils to your list of imports in test/CustomerForm.test.js:

import ReactTestUtils from 'react-dom/test-utils';

Then, begin your test with the following outline:

it('saves existing first name when submitted', async () => {  expect.hasAssertions();});

There are two new pieces of functionality here.

The async keyword appears on the first line, just before our test function definition. This tells Jest that the test will return a promise, and that the test runner should wait for that promise to resolve before reporting on the success or failure of the test.

The hasAssertions expectation tells Jest that ...