Blog Post

Flutter Mobile App Testing

Gain High Performance of Flutter apps with Appium Flutter Driver

Sagar Bagsariya,

Mobile apps have become a need of an hour not only for users but for businesses also. Though cross-platform SDKs like Flutter make the solution cost-effective, developing an app isn’t a question anymore. But how to build high-performing and quality apps is more of a concern. 

Since all sorts of industries use mobile apps to reach and serve their respective clients faster and better, competition evolves. And that demands companies to create high-end apps. To address such requirements, thorough app testing is paramount. 

Looking at the increasing number of Flutter mobile apps, we decided to create this post to help you achieve high performance of Flutter apps. In this blog, we are focusing on Flutter mobile app testing along with a brief on Flutter app development. But first, let us shed some light on Flutter’s specialty that makes it the most favorable cross-platform app development framework.

And yeah, we have revealed our secret of hiring Flutter developers to help the next generation’s CEOs and CTOs be better tech leaders. So, don’t forget to save that guide.

What is Flutter Framework?

Flutter is an open-source mobile app SDK that helps developers to build apps for iOS and Android from a single codebase. It was developed by Google in 2017 and was released as a beta version in May 2018. If you have been looking for a cross-platform mobile SDK that will help you develop native applications for both Android and iOS for free, then you should give Flutter a try.

When it comes to performance, apps built with Flutter tend to perform better than other cross-platform app development frameworks. Flutter’s unique rendering mechanism makes it default for apps to aim to render at 60FPS and up to 120FPS on 120 Hz supporting devices.  

Unlike traditional app development frameworks, Flutter uses Skia to render UI components as if they are a part of a single two-dimensional scene. Skia is a 2D graphics engine developed by Google used by Google Chrome, Fuchsia, Flutter, etc. 

Google’s renowned cross-platform SDK also offers built-in support for code and widgets unit testing.

Features of Flutter Framework and Flutter Architecture

Features of Flutter Framework and Flutter Architecture

Despite ready-to-use and customizable UI components, Google’s Flutter offers many handy features to create highly optimized apps for all supported platforms. For example, 

  • Flutter is a UI framework for building modern mobile apps and interfaces using the power of Dart;
  • Hot reload that makes it possible to review the changes in the code immediately reflected on the UI.
  • Extensive library of customizable widgets for everything from color, menu, search field, et cetera;
  • With Flutter, you can write code once and use it to develop web, desktop, and mobile apps for nearly six different operating systems;
  • Two design specific widget sets to create a native look: Material UI for Android and Cupertino for iOS;
  • The framework also comes with official support for IDE and editors, including IntelliJ IDEA, Emacs, VSCode, and Android Studio;
  • Comprehensive documentation and a growing community never let developers leave any task incomplete;
  • Flutter is written in C, C++, and Dart object-oriented programming language that supports ahead-of-time and just-in-time compilation.

Talking about Flutter architecture, 

Flutter is composed of the Flutter engine and platform, the Flutter library, and Design-specific widgets. The Flutter platform is the interface that runs on top of a device’s native layer, providing a platform-native API to access device features, such as the camera, location, and sensors. It contains the Dart code which is compiled into machine code by the Flutter engine. The Flutter engine is the core of Flutter. The Flutter library contains the majority of code that you write at the Dart language level.

We are now one step away to understand Flutter mobile app testing. So, let’s get it.

How to Create a Flutter App?

How to Create a Flutter App?

Writing Flutter apps is a lot like writing traditional mobile apps, but with a few key differences. The first major difference is that when you write Flutter apps, you use the Dart language instead of Objective-C or Java. 

The second major difference is that instead of building UI components, you use Design-specific widgets to build interfaces. This lets you build complex, unique interfaces without needing to write any code.

Here are crucial steps to get started with your Flutter app development. 

1: Install your preferable IDE;

2: Install the Flutter and Dart Plugins;

3: Create a Flutter Project;

4: Run the Build;

5: Start Coding the Flutter App;

6: Use An External Package, library if needed;

7: Add Stateful and Stateless Widgets to your App as per your requirement.

If you are not a professional developer, you should partner with a Flutter app development company for your project. Poorly written apps not only produce sluggish apps but can also jeopardize your reputation in the market. And no one would want that, would you?

How to test the Flutter App?

How to test the Flutter App?

After knowing Flutter and developing a Flutter app, finally, we are at Flutter mobile app testing phase. First off, know that three types of app tests are there for proper Flutter application testing. 

  • A unit test for testing every single function, method, or class and cross-checking the logic of units under a variety of conditions.
  • A widget test or component test for testing widgets separately, ensuring if UI looks and interacts as expected.
  • An integration test for testing a whole app or a larger part of the app to verify the overall app performance. To run this test, you generally need a real device or an OS emulator as per your targeted platform Android or iOS.

Further on Flutter app testing, we are going to see how integration tests work using Appium Flutter Driver.

Use Appium Flutter Driver

Appium is an open-source test automation framework for use with native and hybrid applications on Android, iOS, and Windows. Appium Flutter driver is a part of the Appium mobile test automation tools for Flutter applications. 

The tool uses WebSocket communication to maintain the WDIO script and start the Flutter driver, sending the request to the particular application. After that, the app-under-test AUT responses to the script via the Appium Flutter Driver.

1- Download the package from GitHub which consists of the Appium Flutter Driver and the Appium Flutter Finder. You can clone the sample project to obtain the WDIO code.

2- Change the directory to the “appium” folder;

3- Use the “appium” command in the console to start the Appium server;

4- Start the emulator and install the required nodejs package

5- Change configuration in test.js”) and run the command “APPIUM_OS=android npm start” to start Appium automation.


To stand out from the crowd, mobile apps have to be fast and function seamlessly. Without rigorous testing, it’s not feasible to make your app high-performing and reliable. However, when you build an app with Flutter, you don’t have to worry much about performance and smooth UI. Google’s cross-platform framework and SDK, Flutter offers amazing tools and integration support for testing your app with automation tools like Appium.
So, if you want to augment your team or hire dedicated Flutter developers, connect us today. We have developers who have been practicing Flutter app development since its inception. Hence, we bet you will only receive the highest-grade software product.

Sagar Bagsariya

Sagar Bagasariya is a Flutter expert and technical team leader with a proven knack for designing and developing efficient, high-performing, user-friendly mobile applications.

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