Testing React

A quick guide on how to test React Native apps in the cloud instead of using testing devices.

Writing unit tests will keep your Gatsby blog bug-free, and leads to more maintainable code. This post covers how you can use Jest and React Testing Library to cover some of your Gatsby blog’s most essential features.

This article will introduce you to Wallaby.js — a JavaScript productivity tool that supercharges your IDE by allowing you to get real-time feedback on your JavaScript tests in your code editor even before saving the file. You will also learn how to use Wallaby.js for testing React applications.

Unit testing has become an integral part of the software development process. It is the level of testing at which the components of the software are tested. In this tutorial, you’ll learn how to test units of a React Native application.

This tutorial shows you how and why to use React Testing Library for low-friction Test Driven Development (TDD).

In this post, we’ll look at two libraries that enable us to carry out UI testing in our React application.

I intent this article to serve as a starter guide for developers who are new to testing React components or even unit testing in general. I won't go into the technical details here, but I'll point you to articles and books that I read and found useful.

How I went from Enzyme to React Native Testing Library and made my unit test more effective and closer to what the users can interact with.

In this article, we’re going to show how React developers can quickly start testing their app with the React Testing Library (RTL).

Building a well-functioning application requires good testing; otherwise, knowing whether your application works as expected would be a matter of guesswork and luck. Jest is one of the best tools available for testing React applications.

Why you shouldn't mock fetch or your API Client in your tests and what to do instead.

In this React Testing Library tutorial, we will go through all the steps necessary to unit test and integration test your React components with confidence.

Learn how to test your React functional components and the state changes for components that use hooks with Jest and Enzyme as testing libraries.

We are happy to announce the release of version 2.0 of React Native Testing Library. For the last couple of weeks, we’ve been working really hard to bring you useful new features and to polish our APIs and their documentation, as well as improve compatibility with other Testing Library implementations.

Cypress 4.5.0 is out with a long-awaited feature: first-class support for framework’s components render.

In this tutorial, I’ll show you how to write unit, integration and end-to-end tests for React applications.

Some mistakes I frequently see people making with React Testing Library.

In a world of myriad tools, it can be difficult to choose the one best suited for your purposes in different scenarios.

This article follows an exercise that starts with a simple website, validates behavior with unit and integration tests, and demonstrates how integration testing delivers greater value from fewer lines of code.

The challenges coming from integrating the tools, the current status of integration, and some best practices to properly test a rendered component.

I always find myself doing dumb mistakes all over the code that could easily be caught by well-written tests. Last fall I attended this conference where this workshop leader said if you really want your developers to write good tests, you have to make the developers accountable. And you do that by fire all the testers. I love testers though.

Get confidence your custom React hooks work properly with solid tests.

Testing is often seen as a tedious process. It's extra code you have to write, and in some cases, to be honest, it's not needed. But every developer should know at least the basics of testing. It increases confidence in the products they build, and for most companies, it's a requirement.

Testing code can be a controversial subject, largely due to the multitude of ways one can go about writing a test.

Have you been looking into testing an Ionic React project, but not sure where to start? In this post, I’ll go over the basics of how to get started as we build out an app using tests.

There are a few reasons you're getting this warning. Here's how you fix it.

This guide explains what unit testing is, why it’s needed and the best practices for small to large React applications.

If you create something, no matter what it is, you should test it before serving it to other people. That way, you can have more confidence and control over your finished product before you roll it out.

In this post, I share how to make React components ready for testing. I cover testing render, component actions, and different states.

Testing your apps is becoming so easy, it's starting to become worth the trouble!

Hooks in React are a new, popular, and extensible way to organize side-effects and statefulness in React components. By composing the base hooks provided by React, developers can build their own custom hooks for use by others.

Wouldn’t it be sweet to be able to test your application straight in production? Not having to wait 20 min to redeploy and roll out your new features?

In this tutorial, we will look at how to do that by making use of a to-do application built with hooks. We’ll cover writing of tests using Ezyme and React Testing Library, both of which are able to do just that.

Writing end-to-end tests for applications helps to ensure applications behave as expected. It also comes in handy when we add new features to existing applications because it ensures the newly introduced features integrate well with our already existing features.

It’s no secret that Enzyme has become the de facto standard for React components testing, but there are other good options around. For example: React Test Renderer.

Detox is an end-to-end testing and automation framework that runs on a device or a simulator, just like an actual end user.

There are a couple of types of testing - most notably unit, integration and e2e (end-to-end) testing. For the purpose of this post I'd like to combine unit and integration tests under the name of "unit tests" (any QA engineers who are reading this, please forgive me).

This is how you get started in testing your application.

End-to-end testing is a technique that is widely performed in the web ecosystem with frameworks like Cypress, Puppeteer, or maybe with your own custom implementation.

Building web applications is not an easy task as of today. To do so, you're probably using something like React, Vue or Angular. Your app is faster, and the code is both more maintainable and readable.

User interface tests are famously finicky and prone to breakage. Let's talk about how to improve this.

Unit testing with Jest is an integral part of projects that are built with React. But we’ve also found that sometimes entire classes of bugs slip through with several Jest configurations, such as the preset included with React Native, and the testing never seems to really cover everything.

A quick React Custom Hooks tutorial — with examples!

In this post, we’ll take a closer look at some of the best ways you can go about testing your React applications.

In this article you will find an introduction to the pixels-catcher project that can be applied to any React Native application and will enable you to do UI snapshots testing of any screen or a component.

We’ll learn how model-based testing can eliminate the need to manually write integration and end-to-end tests, by automatically generating full tests that keep up-to-date with an abstract model for any app.

This post helps explain how thou can test useEffect hook that uses RxJs inside to listen to mouse click and delay the click with RxJs's debounceTime operator.

React components connected to Redux can turn out pretty complex. Thus most people think that testing these complex components can turn out very complex as well. But it shouldn't be complex at all, if you take full control of the Redux store in your integration/unit test for the React component.

With the introduction of React version 16 in 2017, hooks now make it possible to reuse stateful logic between components. However, with these new features, engineers must revisit previously defined conventions for using React. Unit testing is one of these practices.

Making tests too short often leads to poor testing practices and way more tests.

Learn how to test components using dynamic imports in a Next.js application.

The Big Mac index is a purchasing power parity index published by The Economist. Jest fetch testing is a tech task so frustrating that it almost made me quit the industry.

Snapshot tests are a common way to write lightweight component tests. When a snapshot test runs for the first time, it stores its output (e.g. rendered component’s HTML structure) in a snapshot output file.

Integration tests are a sweet spot between cost and value of tests. Writing integration tests for a React app with the help of react-testing-library instead of or in addition to component unit tests can increase code maintainability without impairing development speed.

If you are using Snapshot Tests with Jest for your components, there are a few pitfalls you have to be aware of.

Recently I have been expanding the codebase for my website and blog in order to have a more robust web presence. Part of this of course includes unit testing the source code using Jest.

Testing GraphQL doesn't have to be difficult. This article will explore static and dynamic mocks to make testing GraphQL a breeze.

Why using hooks like beforeEach as a mechanism for code reuse leads to unmaintainable tests and how to avoid it.

Before setting up the test setup with different testing libraries and writing the React component tests, you will need a simple React application which can be tested in the first place.

End-to-end testing (E2E) was always a tedious task with testing frameworks from the past. However, nowadays many people are using Cypress.io for it. Their documentation has a high quality and their API is concise and clean.

In this React testing tutorial, we will introduce Enzyme in our Jest testing environment.

Guillermo Rauch tweeted this a while back. Let's take a dive into what it means.

Jest got introduced by Facebook for testing JavaScript and especially React applications. It’s one of the most popular ways to test React components nowadays. Since it comes with its own test runner, you can simply call Jest from the command line to run all your tests.

When I first started learning to test my apps back in the day, I would get very frustrated with the different types, styles and technologies used for testing, along with the disbanded array of blog posts, tutorials and articles. I found this to be true as well for React testing.

I write tests because I want to be confident about two things: 1) That I didn’t break any existing code. (Existing tests to the rescue). 2)That my new code works as intended.

In this tutorial, we will write tests to cover a todo application I’ve built.

Documenting components with React's PropTypes library is a great way to be notified when you've forgotten to pass a certain prop. Today we're going to see how we can leverage these to make our tests fail when our PropTypes are incorrect.

How your UI code has only two users, but the wrong tests can add a third.

In this tutorial, we’ll explore the different rendering options the utility provides, along with some practical examples.

We’re going to spend some time writing tests together using react-testing-library for a light to-do application I built.

Hopefully, this post can help you understand some key differences between the two libraries and inspire you to explore them for yourself.

Practical advice to help you determine what to test.

In this post, I'll look at an example stateful function component that is tested with react-testing-library. I'll also write the same component into its class component equivalent and show how the class component can be tested with enzyme.

How to apply the "Avoid Hasty Abstraction" principle to your test code.

Testing your frontend application has never been easier before. Within this article, I’ll explain different levels of testing your application as well as the most suited solutions for testing the specified levels.

In this article we'll take a look at how to handle async code in React Testing Library, specifically at how to test and mock a call using Axios.

In this article we'll see how to fire and test events in our React components using the React Testing Library.

In this article we'll take a look at how to handle async code in React Testing Library, specifically at how to test and mock a call using Axios.

While it is important to have a well-tested API, solid test coverage is a must for any React application. Tests increase confidence in the code and helps prevent shipping bugs to users. That’s why we’re going to focus on testing in this post, specifically for React applications. By the end, you’ll be up and running with tests using Jest and Enzyme.

Nock is used to mocking calls to HTTP. It makes it possible for us to specify what URLs to listen to and what to respond with. This is a fairly short article that shows how you use the library nock.

Before we go on to see how to write tests for React Hooks, let’s see how to build a React app using Hooks. We’ll be building an app that shows the 2018 F1 races and the winners for each year.

Today we are happy to announce the next major release of Jest - version 24! It's been 4 months since the last minor release, and 8 months since Jest 23, so this upgrade is a big one, with something for everyone!

A mini-rewrite case study of two testing libraries

Test your first React component using Jest and `react-testing-library`

How can we prepare our tests for React’s new hooks feature?

How we power React component tests and examples at Stripe

Do you avoid testing of components that depend on Redux because you fear the complexity? Are you loosing sleep worrying about configuring huge mock stores for testing the simplest of components? Fear no moarrr!

When I started out writing tests for my React application, it took me some tries before I figured out how to set up my testing environment using Jest & Enzyme.

In this part, we'll finish the UI by adding the number and operator keys before we dive in to adding the basic calculator functionality.

In this post, we'll develop a React app using Test-Driven Development (TDD) with Jest and Enzyme.

The tutorial builds up on a mocked GraphQL API enabling you to write tests for your Apollo Client queries and mutations in React. It answers the question: How to test Apollo Client in React ...

A hands-on guide with live examples.

Testing React components may be challenging for beginners as well as experienced developers who have already worked with tests. It may be interesting to compare your own approaches with the ones we use in our project. In order to cover the codebase, you have to know which components must be tested and which code exactly in the component should be covered.

Learn how to test React components using Jest and Enzyme

Reactjs is a UI library by facebook while Storybookjs is a testing tool for components by representing different states of the component and Jest is another cool unit testing tool by the creators of reactjs for javascript including reactjs.

Building a simple app for teaching concepts around scoring a hand of poker using functional programming.

End-to-end testing is awesome because it mirrors the user’s experience.

In this post, we'll get a deeper understanding of testing components in React by writing more practical and realistic tests.

In this article, I will take you through everything that you need to know to write tests for your React components. I'll also cover some of the best practices and techniques while we're at it.

In this post I’d like to demystify some of these async patterns and highlight the traps that are hidden inside.

Tests should help me be confident that my application is working and there are better ways to do that than shallow rendering.

I am just as careful about not introducing too many tests as I am careful about adding too many dependencies or writing more code than is necessary.

In this part we’ll cover some simple examples on how to test Redux reducers.

Why your tests should be completely isolated from one another and how to do that.

In this part we’ll cover some simple examples on how to test Redux actions.

This article tries to give some hints from a bunch of articles that I have read, trying to find a fast and scalable way to write react tests, with a bit of personal experience and thoughts.

I prefer to apply the KISS Principle when solving problems, so the same goes for testing React-Redux apps.

In this part we’ll cover some simple examples on how to test React components.

Learn how to install and setup Jest and Enzyme for testing React.

I want to talk about some patterns, principles, and tools for testing react native applications.

In this tutorial, we’ll see how to write tests for a React app using Jest and Puppeteer. Testing is an important part of modern web application development, it helps to check if the code you wrote is acceptable and works as accepted. It’s a way of catching bugs in your code before you go “live”.

How to use Puppeteer and Jest to perform End-to-End Testing on your React App

Following the principles of Test-Driven Development (TDD) when writing a front-end React app might seem more difficult than doing the same on the back-end.

A simpler replacement for enzyme that encourages good testing practices.

A React tutorial on how to setup and use React component tests with testing frameworks such as Mocha, Chai, Sinon, Enzyme and Jest.

I started to consider testing with Jest and Puppeteer right after the library came out. Puppeteer has quite an interesting API.

In this post we’ll look at how to configure Visual Studio Code to debug React Components and Jest Unit Tests inside a web application that was created by create-react-app.

Let’s look at how we can write tests for React components that use render props!

Avoiding bugs in your code is important for the end user experience. Choosing the right way to test your code is paramount!

Guillermo Rauch tweeted this a while back. Let’s take a quick dive into what it means.

In this take, let’s explore what it takes to unit test React components. I’ll show the thought process for making your components testable.

Writing unit & end-to-end tests to ship your mobile app with confidence.

Testing is a double-edged sword. On one hand, having a solid test suite makes code easier to refactor, and gives confidence that it works the way it should. On the other hand, tests must be written and maintained. They have a cost, like any other code.

Learn how to test React applications with the Jest JavaScript testing framework.

The bar is set high for today’s mobile apps. First, apps must meet the standard of quality that app markets expect. Secondly, mobile app users are very demanding. Plenty of alternatives are available to download, so users will not tolerate a buggy app. Because mobile apps have become such a crucial part of people’s lives, users won’t be shy about sharing their love or hate for an app — and that feedback gets in front of millions of users in seconds.

How do you know your feature is working perfectly in production? And if something breaks in production, how will you know? Will you wait for a user to report it to you? What do you do when your staging test results do not reflect current production

Should we use react-testing-library or Enzyme? What about snapshot testing? What should be our code coverage? Those are questions we often hear when discussing testing. Those questions are easy to discuss but the answers won't necessarily make us write more reliable code.

You may be wondering, "How do I test React Hooks?" The short answer is: Just like normal React Components! Yay!

I share how I like to write integration tests in React with React Testing Library and Apollo.

Build a ReactJS App workshop.

In this talk, we look at skills-focused path to better testing in the intersection of automation and exploratory testing. We can arrive at the intersection by enhancing our individual skills, or our collaboration skills. What could you do to become one of those testers who companies seek after that work well in the intersection, giving up the false dichotomy?

In this video we cover how to use React Testing Library to test a component being injected with a MobX store.

In this video we'll see how to test using Redux and connected components with the React Testing Library.

Someone asked me to test the hook we used yesterday.

In this video we look at how to test a component with react testing library which contains an asynchronous Axios request that we'll mock out using Jest mocks.

Hooks was released along with a special utility for testing React properly. I'm going to update react-testing-library to make it easier for people to test things properly.

React has a new utility for testing and I'm going to update react-testing-library to use that utility.

In this video we'll see how to fire events (click) and how to wait for elements to appear on the screen when the code is asynchronous.

We'll investigate how to easily test our React components using the React Testing Library an alternative to Enzyme that works alongside Jest. This is an introduction, covering installation, snapshots, finding elements and verifying certain attributes on those elements.

It can be tempting to try and call your custom hook manually and test it that way, but you'll run into the error "Hooks can only be called inside the body of a function component." And for good reason. Let's talk about why that is and the proper way to test a custom React hook.

In this talk Tomasz would like to show you how YOU can start covering your app with e2e tests and showcase coolest features that cypress.io has to offer.

I've got a little gatsby app, let's see how we can add Cypress to test it!

In this talk we'll dive into the approaches and strategies needed to create a great unit test environment for your JavaScript and React applications. We'll examine what makes the perfect test, what to avoid, and how to use more complex features like mocks and spies to enable you to write tests more easily.

This was something I bumped into yesterday and thought I'd share how I test it.

Learn how to test your React and Apollo code using MockedProvider.

True units are awesome to test!

I'm trying to figure out the best way to simplify testing of React components with react-testing-library.

Testing code before its written has some great advantages, but it's not a perfect solution for every scenario. Let's explore some of these situations.

You have more questions. View live and ask in the chat and I'll get through as many as I can!

I got some feedback that there’s confusion around what all of these names and terms are. Let's go over them!

This is wide open! For ~15 minutes I'm all ears! Let's talk testing!

If you want to run your tests in create-react-app with the Chrome Debugger.

In this video I show how I use addMockFunctionsToSchema & MockedProvider to have a powerful auto mocking of data using Apollo's render prop components.

In this video I talk about what is React Testing Library and why you might want to use it.

Test React components in complete isolation, in integration, or a mix of the two? Jack and Kent will discuss their differing opinions about Testing React applications and why they have come to their conclusions.

There's an interesting new library called "from-html". Let's see what it'd be like to create a from-html-testing-library :)

Sometimes it's just really nice to step through your code line-by-line. Here we'll cover how you can run your jest tests in Chrome's DevTools using node --inspect-brk.

How to Test React components that use React.createPortals

Do you test actions, reducers, selectors, and components in isolation as unit tests? Or do you test the connected components with the actual store wired up as integration tests? Here are my thoughts.

How to setup react-testing-library to work with create-react-app

Lots of people make the assumption that react-testing-library is good for React component integration testing, but not very useful for unit testing because it (intentionally) doesn't support shallow rendering. Let's see how you can do unit testing with react-testing-library

Now there's only one way to do it, but it can be customized to suite your needs.

The react-testing-library is a very light-weight solution for testing React components.

Let's rethink what it means to ship applications with confidence and what it takes to get there. With improved tools and practices, we can be more certain that what we're shipping to our users will work the way it's intended.

In this video we'll look at a function that makes an HTTP request using the axios library to the Unsplash API and figure out how we can test it using a fake/mock version of axios to avoid performing real HTTP requests. We will be using Jest and some mocking functionality that it provides.

In this video we'll cover how to test React components that contain asynchronous code using mocks in Jest. We'll refactor our component to make it more easily testable and mockable, allowing the test to run without making an actual AJAX request.

In this video we talk about how to test components in React within create-react-app, how to configure Jest with Enzyme and Sinon, how to test with snapshots, simulate clicks, and interact with DOM elements through Enzyme.

This is a recording from my laptop at the Assert.js conference workshop.

In this post we’ll look at how to configure Visual Studio Code to debug React Components and Jest Unit Tests inside a web application that was created by create-react-app.

Automated tests are an important part of raising your confidence when releasing software. They can speed you up or slow you down depending on how you write them and which form of testing you focus your test writing on. In this talk, we’ll cover the value of automated testing and where your efforts should be focused to strike the best balance of confidence and effort.

Dave Ceddia talks about using Jest's snapshot testing to verify your APIs are working as expected.

I will discuss our Three Layers of Testing (tm) we use when developing new features for one of our high traffic web applications at the ANWB. (1) Unit testing React & Redux Components, (2) Behavioural testing our interactive React Components and (3) Integration testing our entire application.

Got some great feedback and fixed some regressions, then added more tests.

This is the last bit of testing I needed to do to get to 100% automated code coverage!

I'm finally solidifying things and got a bunch of tests written.

In this one I write tests for pure functions as well as mocking out DOM APIs. It's pretty wild.

In this screencast we'll look at a React component that needs refactoring and splitting up, and refactor it whilst using and updating the tests to ensure all functionality is working.

Jest has become one of the coolest things in testing JavaScript and React. In recent months, the Jest team has made huge strides with the testing framework and it's a pretty amazing tool.

We'll discuss the best tooling and approaches for building ReactJS applications in the NodeJS environment and in the browser using React TestUtils and other third party libraries that make it easy to test your components. We'll see how to build components in a way that makes them more maintainable, testable and easier to work with.

In this course we are going to work through properly setting up Enzyme with Jest to test rendered components.

A video series to enable you to test React components thoroughly, refactor with confidence and abstract logic out of components

Learn how to build and launch React web applications using React v16, Redux, Webpack, React-Router v4, and more

Learn how to test, debug, and optimize your React code with tools like Jest, Chrome, ESLint, and flow.

Create automated testing so you can be sure you’re maintaining the highest quality JavaScript applications possible!