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.

Testing React Apps with Jest and React Testing Library_468 x 60 copy 3.png

file.tar.gz

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

# Understanding snapshot testing

A **snapshot test** defines the result of a test and stores the result in a snapshot the first time the test is executed. On subsequent test executions, the result is compared against the baseline snapshot, and if there is a difference, the test fails.

Snapshots can be useful when checking result objects or arrays. They can also be used to check portions of the DOM.

# Checking for unexpected changes in objects

[This lesson’s project](https://github.com/carlrip/testing-react-apps-with-jest-and-rtl-code/tree/master/Chapter-03/Lesson-07/start) is similar to previous lessons. We have functions to get a person and search for people. There is a happy path test for each function as well, which passes.

A copy of the starter project is in the code widget below:

Learn to use snapshot testing in this lesson. 

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

Using Snapshots

Understanding snapshot testing

Checking for unexpected changes in objects