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May 18, 2021

What Is the Flutter Framework?

Mobile Application Testing

Table of Contents: 

1. What Is the Flutter Framework?

2. Why Is Flutter Used?

3. Benefits and Drawbacks of the Flutter Framework

4. How to Test Flutter Apps

Flutter is the newest framework to make a splash in the world of mobile app development. Here, we delve more into what the Flutter framework is, its benefits and drawbacks, as well as the different ways to test a Flutter application.  

What Is the Flutter Framework? 

Flutter is Google’s free and open-source UI framework for creating native mobile applications. Released in 2017, Flutter allows developers to build mobile applications for both iOS and Android with a single codebase and programming language. This capability makes building iOS and Android apps simpler and faster.  

The Flutter framework consists of both a software development kit (SDK) and their widget-based UI library. This library consists of various reusable UI elements, such as sliders, buttons, and text inputs. 

Developers building mobile applications with the Flutter framework will do so using a programming language called Dart. With a syntax like JavaScript, Dart is a typed object programming language that focuses on front-end development. 

Why Is Flutter Used? 

Although Flutter is a newer cross-platform framework, more and more companies have chosen Flutter over frameworks such as Xamarin, Cordova, and React Native.  

Some of the top reasons why development teams choose Flutter include: 

  • Increased productivity. Using the same codebase for iOS and Android saves both time and resources. Flutter’s native widgets also minimize time spent on testing by ensuring there is little to no compatibility issues with different OS versions.
  • Easy to learn. Flutter allows developers to build native mobile applications without needing to access OEM widgets or use a lot of code. This, in addition to Flutter’s particularly appealing user interface, makes the mobile app creation process much simpler.  
  • Great performance. Users report that it is difficult to notice the difference between a Flutter app and a native mobile app.
  • Cost-effective. Building iOS and Android apps with the same codebase is essentially building two apps for the price of one.  
  • Available on different IDEs. Developers are free to choose between Android Studio and VS Code to edit their code on Flutter.  
  • Great documentation & community. Flutter has many great resources to answer your questions, thanks to its ample documentation with easy-to-follow use cases. Flutter users also benefit from community hubs like Flutter Community and Flutter Awesome for exchanging ideas.  

Benefits and Drawbacks of the Flutter Framework 

Although Flutter is not yet widely adopted, an increasing number of tech companies have started realizing its potential. Some notable Flutter applications include Google Ads, eBay Motors, Philips Hue, and Xianyu from Alibaba.  

Let us look at some of the benefits that Flutter offers, as well as some of their drawbacks. 

Benefits of Flutter App Development 

Flutter offers a wide range of benefits for business folks and developers alike. Flutter offers good quality for reasonable costs, as well as great usability and speed. 

  • Development goes faster when the same code is used for both iOS and Android applications. Flutter’s singular codebase speeds up time-to-market while cutting mobile app development costs significantly. 
  • Flutter app performance is equivalent to that of native real-time applications. Unlike other frameworks, Flutter apps do not need a bridge to interact with native components. Since these bridges typically cause performance issues, this gives Flutter a decided advantage. 
  • Flutter’s “hot reload” feature allows developers to change the code on emulators, simulators, or real devices, and see results in real-time. The changed code is then reloaded immediately while the app is running. No restart required. Hot reloads make building UIs, adding features, and bug fixing simpler than ever.  

Drawbacks of Flutter App Development 

While Flutter app development presents a lot of positives, it is also important to consider the lesser aspects of the framework: 

  • Flutter is relatively new. While Flutter offers many plugins and UI components, frameworks like Xamarin and React Native offer a much larger selection. While Flutter will not be the new framework on the block forever, this is the situation now. 
  • Dart is not very popular. While it is a great programming language, developers are often much more likely to consider languages such as Java or Kotlin.  
  • Some components are only available for iOS or Android, but not both. These types of components more often support Android since Flutter comes from Google, and Android developers are typically more interested in Flutter than iOS developers.  

How to Test Flutter Apps 

Automated Flutter tests fall into three major categories: 

  • Unit testing 
  • Widget testing 
  • Integration testing 

While unit tests test a single function, class, or method, widget tests (also known as component tests) test a single widget. Unit tests and widget tests make up most Flutter tests, tracked by code coverage. Integration tests test either a large part or the entire application, covering all the important use cases. 

Testing a Flutter application With Perfecto
Testing a Flutter application With Perfecto

Let us understand the purpose of each type of testing with the following overview.: 

Unit Testing 

Unit tests for a Flutter app validate the behavior of a single method, function, or class. In other words, unit tests ensure that the method under test provides the expected result based on a given input. They help users write more testable and maintainable code. 

Users can run automated unit tests through the Flutter plugins for IntelliJ and VSCode. In addition to their support for running tests, IntelliJ and VSCode also provide the fastest feedback loop and allow users to set breakpoints.  

Widget Testing 

Widget tests, also known as component tests in other UI frameworks, verify that the widget’s UI looks and behaves as expected when responding to certain interactions. It is much more comprehensive than a unit test, as it involves multiple classes and requires a test environment that provides the appropriate widget lifecycle context. 

Yet at the same time, the widget’s test environment is a much simpler implementation than a more developed UI system. Flutter users should write widget tests for all common widgets being used for their applications. 

Integration Testing 

Integration tests test either the entire app or a large portion of the app. These tests verify application performance and ensure that all the widgets and services under test work together properly.  

Flutter users perform integration tests on either real devices or virtual devices, such as simulators and emulators. These tests run in two parts: deploying the application under test to the device (real or virtual) and then driving the application from a separate test suite. This checks to make sure that everything is working together as expected.  

Bottom Line 

The Flutter framework presents exciting opportunities for mobile app developers and businesses alike. Building iOS and Android applications with the same codebase on a highly user-friendly interface makes mobile app development fast and cost-effective.  

Combined with Perfecto, organizations can release high-quality Flutter applications quickly and easily. Learn more about our platform to learn about our Flutter testing capabilities in more detail. 

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