Similarly, for assert operation, you can use expect(). For example, in the above demo, you can see click() for clicking in an element, type() for typing, etc.

In Jest, there are plenty of functions to simulate UI activities. You can install the latest version of jest from NPM usingĬonst puppeteer = require ( ' puppeteer ' ) describe ( ' Todo React ', () => ) So, some features might be different if you are using some other version. While writing this blog, I am using jest version 24.9.0. The version is important because jest is a dynamic library and different versions of jest might work differently. It configures jest based on whatever argument you give while running jest. Jest CLI is a tool that you use from the command line to run and provide configuration options to jest. Jest is the test runner library for creating, executing, and structuring tests. If your app is not yet ready for testing then you can just clone this basic todo app and follow along. Before getting started with Jest, You need to have npm and an app for which you will be writing tests. Some commands will be different if you have another OS installed on your computer.

By default, this library runs the browser in headless mode, but it can be also configured to run Chrome or Chromium fully (non-headless). It can work with Chrome, Chromium, or Firefox. Puppeteer provides a high-level API to control the browser. Puppeteer is a Node library that is used for browser automation. It also comes with built-in mocking and assertion abilities. Jest is built on top of Jasmine and Mocha but some additional features like snapshot testing and parallel test execution are provided by Jest. It is a great testing library and many react team members are involved building it, so it happens to work very well for testing react applications. The Jest is a javascript testing tool that is installed via NPM or Yarn and run via the command line. 'In Jest, there is truth' -William Shakespeare.īy using Jest, you will know the truth about your application.

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