Gain insights into writing automated tests for React apps with Jest and React Testing Library. Learn about simulating user interactions and testing asynchronous parts to enhance app reliability.

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Jest - lesson 2

Jest with run command

Jest verbose

Jest coverage

Jest snapshot update

Jest react

Jest react-npm start

Jest react-copy

Jest react-C4

Jest react-C6

Jest react start c6

Jest - lesson 2-copy

Jest sandbox

Jest coverage-copy

Jest react-C4-start

Jest react-C4-start-5000

Jest react-npm start-5000

Jest react start c6-5000

Jest react-C8

The skills acquired from this course will allow you to write automated tests on your React app using Jest and React Testing Library, which are the de-facto testing tools for React. These tests will allow you to ship new versions of your app with confidence. The tests will also allow you to increase your release frequency, allowing you to get features to your customers quicker.

You will learn how to write robust tests that are resilient to breaking when code is improved and refactored, reducing maintenance costs.
The course will teach you how to simulate a user interacting with the app. Beyond that, it will also teach you how to robustly test asynchronous parts of the app.

Regular quizzes and exercises will reinforce knowledge throughout the course.

Testing React Apps with Jest and React Testing Library

It automatically removes test elements from the DOM at the end of the test.

It helps avoid referencing implementation details in tests.

It automatically adds a container element for the component being tested.

**(Select all that apply.)** What are the benefits of using React Testing Library for component testing?

(Select all that apply.) What are the benefits of using React Testing Library for component testing?

The DOM doesn't contain an element with the text content of `"test"`.

React Testing Library hasn't been installed.

`jest-dom` hasn't been imported for use in the test.

We have a test that is failing. Here is the line of test code and the error:

```javascript
// 💥 TypeError: expect(...).toBeInTheDocument is not a function
expect(screen.getByText("test")).toBeInTheDocument();
```

What is the problem?

We have a test that is failing. Here is the line of test code and the error:
<pre><code class="language-javascript">// 💥 TypeError: expect(...).toBeInTheDocument is not a function
expect(screen.getByText(&quot;test&quot;)).toBeInTheDocument();
</code></pre>
What is the problem?

A test is failing because the DOM doesn't contain an element with text content of `"test"`. Here is the expectation:

```javascript
expect(screen.getByText("test")).toBeInTheDocument();
```

Will a representation of the DOM be output to the console?

A test is failing because the DOM doesn’t contain an element with text content of <code>&quot;test&quot;</code>. Here is the expectation:
<pre><code class="language-javascript">expect(screen.getByText(&quot;test&quot;)).toBeInTheDocument();
</code></pre>
Will a representation of the DOM be output to the console?

**(Select all that apply.)** What file(s) can Jest’s configuration settings be stored in? 

(Select all that apply.) What file(s) can Jest’s configuration settings be stored in?

Which Jest configuration setting can be used to mock out image resources?

Which Jest configuration setting can be used to mock out image resources?

What Jest configuration setting can be used to import `jest-dom` into every test file?

What Jest configuration setting can be used to import <code>jest-dom</code> into every test file?

What statement in a test will output the DOM representation of a test component's container element? The container element is contained within a variable called `container`.

What statement in a test will output the DOM representation of a test component’s container element? The container element is contained within a variable called <code>container</code>.

This quiz will test what you have learned in this chapter.

Introduction

Getting Started with Jest

Using Matchers

Getting Started with React Testing Library

React Testing Library Queries

Firing Events

Mocking

Testing Different Types of Components

Appendix

Quiz Yourself on React Testing Library