Learn Jasmine, Jest and Mdx

In this collection, we build a minimal flashcard application using React, primarily focusing on function components and the hooks API. To make sure we can understand and maintain existing code, there are also a few lessons toward the end that use class components so you can get familiar with the syntax. We cover important React concepts, and sprinkle in libraries that are pretty standard in the ecosystem like @reach/router, Jest, and React testing library. We start with create-react-app so we can get right into it without worrying about configuring tooling. There's [a separate course for that here](https://egghead.io/courses/modern-javascript-tooling-with-react?af=5mx0ie)

jest

Build a React App with the Hooks API

In this course we are going to work through properly setting up Enzyme with Jest to test rendered components. This includes the nitty gritty of making our testing environment work with various versions of React. After we get our environment setup ready, we’ll work through the different ways we can render a component within our test pages. With a rendered component we can now test component methods and properties to assert that they are what is intended. 

React is one of the web’s most popular frameworks for building JavaScript applications. 

If you know what you’re doing, React can drastically simplify how you build, use, and maintain code.

Whether you’re a React newbie or you’re ready for advanced techniques, you can level-up with egghead. Explore our in-depth courses, lessons, and community resources to build more powerful applications and crack open your career.

react

Test React Components with Enzyme and Jest

Best practices for building & testing redux applications have changed dramatically over time. This course aims to be a comprehensive and up-to-date resource for those seeking to confidently test their redux apps. Whether you're just getting started or want to improve on your existing testing strategy, there will be something in this course for you.

This first few lessons of this course look at how to add jest to an existing react/redux application that was built on top of [vite](https://vitejs.dev/). We cover basic functionality like using `npm test` vs `npx jest` and generating and using [code coverage](https://jestjs.io/docs/cli#--coverageboolean) to inform our testing strategy.

The next 10 or so lessons cover the specifics of unit testing the redux code in our application. We'll go over how to test reducers, selectors and thunks. As part of this we'll touch on mocking APIs and using [Redux Mock Store](https://github.com/reduxjs/redux-mock-store) as well as running actions through our applications' actual reducers to broaden our test coverage.

In the final part of this course we'll look at how we can test our redux connected react components using the various utilities that come with the [React Testing Library](https://testing-library.com/docs/react-testing-library/intro/). We'll cover simulating various kinds of user input with the [User Event Module](https://testing-library.com/docs/ecosystem-user-event), populating our redux store with test data, using [jest spies](https://jestjs.io/docs/jest-object#jestspyonobject-methodname), how to wait for asynchronous tasks to complete, and several approaches for finding & asserting that visual elements exist on the page.

This course is built on top of content that was created for the [Modern Redux with RTK and TypeScript](https://app.egghead.io/playlists/modern-redux-with-redux-toolkit-rtk-and-typescript-64f243c8) course and I highly recommend you start there if you haven't completed it already. It does expect a *basic* familiarity with react, redux and jest. TypeScript is used in these lessons, but is not a major focus and hopefully won't distract you too much if you prefer plain JavaScript.

No matter your experience level with redux and testing react applications, I'm confident your abilities will level up as you watch this course and follow along with the examples.

Thank you!

Confidently Testing Redux Applications with Jest & TypeScript

MDX has grown rapidly since the first commit two and a half years ago. We'd like to celebrate our accomplishments so far, and talk about what lies ahead. We've got lots of plans.
Learn how MDX increases developer productivity, improves educational content authoring, and even peek behind the curtains to see how MDX works.

MDX is an authorable format that lets you seamlessly use JSX in your markdown documents. You can import components, like interactive charts or notifications, and export metadata. This makes writing long-form content with components a blast.



MDX Conf 2020

AngularJS is an open-source JavaScript framework, maintained by Google, that assists with running single-page applications. Its goal is to augment web-based applications with model–view–controller (MVC) capability, in an effort to make both development and testing easier.

angularjs

In this lesson Trevor looks at testing AngularJS controllers with scope inheritance with Jasmine and test spies.

Testing Controllers With Dependencies

Custom Jasmine Matchers are a great way to keep your AngularJS Unit Tests clean and tidy. We want to make expectations **readable** and express the intent of the test. Custom matchers help to accomplish this.

Custom Jasmine 1.3 Matchers

An introduction on unit testing a ReactJS component using Webpack and Jasmine. Learn how to use Webpack to package and import dependencies plus take advantage of the babel-loader to write a simple Jasmine spec using the latest ES6 syntax.

Unit testing a React component using Jasmine and Webpack

AngularJS provides helpers for convenient testing of your application. In this lesson you will learn how to test a basic controller with Jasmine and Angular.

Testing a Controller

In this lesson John shows some tricks for speeding up your test suite. He digs into some handy features of WebStorm, including the *ddescriber* plugin, as well as some alternative methods for Jasmine for selectively running your tests.

Speed Testing with WebStorm and Jasmine

One of the beautiful things about dependency injection in your AngularJS apps is the ability to replace dependencies in your unit tests. In this lesson Trevor looks at how to configure Jasmine spies as injectable replacements for dependencies for testing.

Inject Jasmine Spies With $provide

Jest is a painless JavaScript unit testing framework from Facebook. It is designed to be super easy to setup and is packed full of powerful features. In this lesson we see how easy it is to add to your TypeScript project. This will be followed by a quick example application.

Getting started with Jest using TypeScript

Testing is a first class citizen in AngularJS. It is at its heart and soul. This lesson demonstrates using Karma to write a simple unit test for a Filter.

Unit Testing AngularJS

Unit testing a React component using Webpack and Jasmine, can involve slow and repetitive tasks when confirming that tests are passing when your code changes. For example, manually running commands instructing webpack to compile code plus refreshing the browser. This lesson demonstrates how to speed up your development time by automating these tasks using webpack-dev-server.

Reloading React component tests using webpack-dev-server

React Storybook allows for easy snapshot testing integration with Facebook's Jest testing framework. Snapshot testing allows you to capture the state of your UI and then notify you when that UI has been altered. We can easily create and update snapshots with Storybook!
 




Jest Snapshot Testing with React Storybook

Using Jasmine, this lesson will look at testing an AngularJS service.

Testing a Service

The reducer is at the center of how Redux manages state. In this lesson we’ll create a reducer function and see how Redux takes in state and actions and returns updated state. We’ll write and run unit tests using Jest to verify that our reducer function is working as expected.

Create a Redux-Style Reducer Function

In this lesson, I use Enzyme and Jest's Snapshot functionality to write an integration test for a component called CounterConsumer that consumes the Render Prop component Counter. This integration test is great because it doesn't necessarily care that CounterConsumer uses Counter behind the scenes, just that it works when integrated.

Other resources:
[Testing ⚛️ components using render props](https://blog.kentcdodds.com/testing-%EF%B8%8F-components-using-render-props-5623ab1814c)


Integration test a React component that consumes a Render Prop 

In this lesson, I use Enzyme and Jest to unit test a Counter Render Prop component. Writing integration tests are perfect for components that consume a Render Prop component. Likewise, unit tests are important to write for the Render Prop component itself, as you can test each individual unit that makes up the component.

Unit test a React Render Prop component

In order to get up and going with Enzyme and Jest, some configurations are required. We will need to install some babel plugins, create a specific package json script, and depending on which version of Jest, add Jest configurations to our package.json. 

Install Enzyme and Configure Jest

Within some of React’s releases there are major breaking changes that require different setups for Enzyme. In this lesson we are going to walk through how to setup your testing environment with some of these releases. 

Test Against Different React Releases with Enzyme

In this lesson we will shallow render a component and pass through different config options. Shallow rendering is useful to test components as individual units. This helps ensure that tests aren’t indirectly asserting on behavior of child components. We’ll also use the debug method to show how we can easily view our component for debugging purposes. 

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