UI Testing of React Native Apps

React Native is a popular web development framework that has been successfully adopted by hundreds of businesses worldwide, such as Pinterest, Uber, Facebook, etc., across different industries.

By having a single code base generate native applications for both iOS and Android, React Native has taken hybrid app development to the next level of stability and overall better performance.

This article discusses what React Native is, the major difference between React and React Native, and how to perform UI Testing of React Native Apps with examples.

What is React Native?

React Native is an open-source JavaScript framework that is designed for building apps on multiple platforms like Android, iOS, and also web applications. It is based on React and plays a vital role today in mobile app development.

ReactJS (web) and React Native (mobile) both of these frameworks were developed by Facebook. React Native was a Hackathon project that was aimed at solving the company’s biggest trouble of maintaining two different code bases for their app development, which led to multiple problems such as work duplication and code maintenance. Thus, solving these problems with code reusability by utilizing the same code base for different platforms, thus saving time and effort.

It uses JavaScript to compile the app’s user interface but uses native-OS views instead of WebViews that are used by other contemporaries. It allows code implementation (for more complex features) in OS-native languages (Java and Kotlin for Android; Swift and Objective-C for iOS; etc.).

Difference between React and React Native

React is an open-source JavaScript library that is used on the front-end to build faster and more reliable User Interfaces for web applications. It is based on the concept of reusable components.

Similar to React Native, React was also developed by Facebook in 2011 as a possible solution to their scalability problems arising when Facebook ads were growing immensely. As a result of the immense growth, UI performance was significantly down due to constant updates. React solved the scalability issue, and, in 2012, it was also used on Instagram when Facebook acquired it.

React Native, powered by React and developed by Facebook, is a mobile framework that allows building near-native apps built using JavaScript.

How does React Native work?

Unlike its competitors like Ionic, React Native does not rely on WebViews, but on the real components provided by native platforms since, React Native works on a Dynamic Runtime approach.

It utilizes JavaScript to produce the app’s interface. React Native has built-in access to the native views and components and can utilize native-written code. It allows the API access to OS-specific features inside the app. But how does this happen exactly?

React Native uses the concept of bridge, which allows asynchronous communication between JavaScript and the Native elements. This bridge concept is the main reason behind React Native’s flexibility. Although Native and JavaScript elements are completely different technologies, they are able to communicate through the concept of bridge.

This type of architecture used by React Native offers the benefit of using many OS-native features. However, it also comes with enormous challenges, such as constant use of bridges inside the app sometimes even slows down its performance significantly.

Here’s a visualization of the bridge concept:

Source: Hackernoon

Advantages of Using React Native for UI Testing

Now that it has been discussed in the previous sections what React Native is and how it differs from React, let’s take a quick glance over some of its major advantages:

• Cost efficiency: Since the same codebase can be used on multiple platforms, React Native proves to be highly cost-efficient.
• Code reusability and faster development: Utilizing the same code base for different platforms carries other benefits: faster development and hence, faster time-to-market, cheaper maintenance along with a smoother onboarding process for new developers joining the project.
• Performance: React Native’s bridge concept helps in achieving considerably faster performance as compared to other cross-platform solutions. Also, it is not as laggy as other solutions since it allows usage of natively written code.
• Simple UI: React Native development uses React JavaScript to build the app’s interface, which makes it more responsive and faster with reduced load time, resulting in an overall better user experience.
• Fast refresh: Fast refresh allows developers to run the app while updating it to new versions and modifying the UI. Changes are visible immediately, and the developer is spared from rebuilding the entire app.

What makes React Native unique?

The major difference between React Native and other cross-platform development solutions is that it doesn’t render WebViews in its code. It runs on its actual, native views and components. This is one of the major reasons behind React Native’s spectacular success.

Apps built using React Native: Examples

React Native has been used to build some of the most popular mobile applications which include:

• Facebook
• Instagram
• Pinterest
• Skype
• Walmart
• UberEats

UI Testing of a real React Native Mobile App

UI is essential for creating a great user experience. Let’s understand how to perform UI testing of React Native Mobile Apps by testing a real React Native Mobile App – Pinterest. To ensure a seamless user experience across different devices, testing the React Mobile App across different real devices using BrowserStack App Live.

Step 1: Log in to BrowserStack App Live, and choose any desired Android or iOS real device.

Step 2: Install the test application via any of the available options. In this case, we are using Play Store for installing the app.

Step 3: Once, the app is installed, log in to the same and perform the test scenarios. In this case, we are checking room decor ideas on Pinterest and ensuring the user experience is seamless and consistent across different devices and OS versions.

Test UI of React Native Apps 

Here are a few cross-device app compatibility tests conducted on different devices combinations using BrowserStack’s AppLive:

Google Pixel 6 & Android Version 12

Samsung Galaxy S21 & Android Version 11

Test Result

As observed, on all of the devices, the React Native mobile app of Pinterest worked consistently with seamless functionality and is providing the same user experience.

UI Automation Of React Native Application

The article covered manual UI tests of a React Native Application across different devices. However, for regression testing of features in application, it becomes harder to test manually. Automated tests help ensure that the mobile application under test performs correctly and gives seamless user experience before going live.

With BrowserStack App Automate, you can easily automate the tests of React Native mobile applications across thousands of real iOS and Android Devices securely, by integrating with different testing frameworks Cypress, Appium, Espresso, etc.

Running the automation tests on a real device cloud reduces the time needed to be spent on configuring and maintaining the device infrastructure and will help in dedicating more time towards debugging and fixes. This will eventually lead to a robust test framework ensuring better test coverage and a better product to the end user.

Whether you perform manual or automated UI tests of React Native Apps, testing them on real devices is a best practice as opposed to Emulators and Simulators. Using BrowserStack Real Device Cloud, you can access 3000+ browser-device combinations offering a wide coverage, allowing you to test end to end under real user conditions.

Test on Real Device Cloud