Client-Side Testing With Jest, React Testing Library, and Cypress

Client-side testing is a massive topic. If you’ve read “Developing a Client-Side Testing Strategy,” you’ll have been introduced to the best practices and challenges faced when selecting a client-side testing strategy.
We could choose to take a deeper look at any of the following below:

• Testing devices and different browsers where users view your product
• Static types and linters to validate values and syntax during development
• Testing CSS, comparing the final design, and markup results
• Testing a native application and the testing suites available
• Manual testing practices
• Using visual libraries, e.g., Storybook

But for now, let’s keep it simple and do some unit, integration, and end-to-end tests.

#react #cypress #programming #javascript #jest

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How native is React Native? | React Native vs Native App Development

If you are undertaking a mobile app development for your start-up or enterprise, you are likely wondering whether to use React Native. As a popular development framework, React Native helps you to develop near-native mobile apps. However, you are probably also wondering how close you can get to a native app by using React Native. How native is React Native?

In the article, we discuss the similarities between native mobile development and development using React Native. We also touch upon where they differ and how to bridge the gaps. Read on.

A brief introduction to React Native

Let’s briefly set the context first. We will briefly touch upon what React Native is and how it differs from earlier hybrid frameworks.

React Native is a popular JavaScript framework that Facebook has created. You can use this open-source framework to code natively rendering Android and iOS mobile apps. You can use it to develop web apps too.

Facebook has developed React Native based on React, its JavaScript library. The first release of React Native came in March 2015. At the time of writing this article, the latest stable release of React Native is 0.62.0, and it was released in March 2020.

Although relatively new, React Native has acquired a high degree of popularity. The “Stack Overflow Developer Survey 2019” report identifies it as the 8th most loved framework. Facebook, Walmart, and Bloomberg are some of the top companies that use React Native.

The popularity of React Native comes from its advantages. Some of its advantages are as follows:

• Performance: It delivers optimal performance.
• Cross-platform development: You can develop both Android and iOS apps with it. The reuse of code expedites development and reduces costs.
• UI design: React Native enables you to design simple and responsive UI for your mobile app.
• 3rd party plugins: This framework supports 3rd party plugins.
• Developer community: A vibrant community of developers support React Native.

Why React Native is fundamentally different from earlier hybrid frameworks

Are you wondering whether React Native is just another of those hybrid frameworks like Ionic or Cordova? It’s not! React Native is fundamentally different from these earlier hybrid frameworks.

React Native is very close to native. Consider the following aspects as described on the React Native website:

• Access to many native platforms features: The primitives of React Native render to native platform UI. This means that your React Native app will use many native platform APIs as native apps would do.
• Near-native user experience: React Native provides several native components, and these are platform agnostic.
• The ease of accessing native APIs: React Native uses a declarative UI paradigm. This enables React Native to interact easily with native platform APIs since React Native wraps existing native code.

Due to these factors, React Native offers many more advantages compared to those earlier hybrid frameworks. We now review them.

#android app #frontend #ios app #mobile app development #benefits of react native #is react native good for mobile app development #native vs #pros and cons of react native #react mobile development #react native development #react native experience #react native framework #react native ios vs android #react native pros and cons #react native vs android #react native vs native #react native vs native performance #react vs native #why react native #why use react native

Interaction Testing with React Testing Library

Testing is complicated. I’ve certainly never been good at it. For the longest time, I’ve only been focused on basic function input-output unit tests. Why? Because they were easy — you didn’t need to render HTML, you didn’t need to query DOM elements, you didn’t need to interact with said DOM elements. But of course, React component testing is a necessity for any mature codebase. And it finally came time for me to sit down and figure it out.

That’s when I discovered React Testing Library. And suddenly, everything seemingly became much simpler. All the complexities that I’ve encountered, but not understood, that made me put off React component testing disappeared. Hopefully, the same will happen for you.

#react-testing-library #unit-testing #react #jest #interaction-testing

Client-Side Testing With Jest, React Testing Library, and Cypress

Client-side testing is a massive topic. If you’ve read “Developing a Client-Side Testing Strategy,” you’ll have been introduced to the best practices and challenges faced when selecting a client-side testing strategy.
We could choose to take a deeper look at any of the following below:

• Testing devices and different browsers where users view your product
• Static types and linters to validate values and syntax during development
• Testing CSS, comparing the final design, and markup results
• Testing a native application and the testing suites available
• Manual testing practices
• Using visual libraries, e.g., Storybook

But for now, let’s keep it simple and do some unit, integration, and end-to-end tests.

#react #cypress #programming #javascript #jest

Simulate Browser Interactions with Testing Library’s UserEvent

My Journey

Like most, when I first started using Testing Library, I used Fire Event to test component interactions. After all, this API shipped with the library itself and was used in the test examples in the documentation. But I soon discovered that Fire Event had serious limitations. I would try clicking something and the expected effect did not happen. Why?

Browser Events

To understand this issue, we need to better understand browser events. When a user clicks something in their browser, multiple events are triggered — mouseDown, mouseUp, click, and focus. Similarly, when typing something, the keyDown, keyUp, and keyPress events all trigger! Because a single user interaction could trigger multiple events, developers have multiple options for implementation. This is where I ran into my issue.

Fire Event

Fire Event, unfortunately, requires you to use the method for the corresponding event handler to trigger. If an element has an onClick event handler, I have to use fireEvent.click; if an element has an onMouseDown event handler, I have to use fireEvent.mouseDown. In other words, I need to know the exact implementation of the event handler to successfully use fireEvent.

#react #jest #integration-testing #unit-testing #react-testing-library #react native

React Testing Tutorial (Jest + React Testing Library)

Learn how to write unit tests for your React components using Jest and the React Testing Library.

We will be writing some unit tests for React components using the Jest framework (https://jestjs.io/). We will begin by creating a react app using create-react-app. Then we will create a component & write some unit tests for it. We will finish by writing some snapshot tests to verify changes to the component tree.

Don’t forget to Subscribe here: https://www.youtube.com/channel/UCWkzkhQ3syxBjjAYwqCbzYg?sub_confirmation=1

#react #jest #react testing library