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Table of contents
Flutter app Testing
Types of Testing
Unit Testing
Widget Testing
Steps involved
Integration Testing
Integration Testing of Units and Components.
Integration Testing of the System 
Continuous Integration Testing
Frequently Asked Questions
What is a flutter app?
How many testing steps are there to test a flutter application?
What is automated testing in the Flutter framework?
Last Updated: Mar 27, 2024

Flutter app testing

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App testing plays a very critical role in developing a robust application. It is a process of identifying flaws in any software application by utilizing scripts, tools, or test automation frameworks. It enables teams to ship bug-free and stable software into the actual world. It also allows teams to detect flaws early in the development process, reducing development time. In this article, we shall be discussing more of it.

Flutter app Testing

Testing is termed a crucial part of an application's development life cycle. It guarantees that the app is of good quality. Testing necessitates meticulous preparation and execution. It's also the phase of the procedure that takes the longest.

The Dart programming language and the Flutter framework support automated application testing.

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Types of Testing

Three sorts of testing techniques may be used to test an application thoroughly. The following is a list of them:

  1. Unit Testing: Unit testing is a software development technique in which the minor testable pieces of an application, referred to as units, are examined separately and independently for appropriate functioning. Software developers and, on occasion, QA employees use this testing approach during the development process.
  2. Widget Testing: The most straightforward way to test an application is to use unit testing. It is based on guaranteeing the validity of a piece of code (generally, a function) or a class method. However, it is the least effective method for locating flaws because it does not mirror reality.
    A widget test (a component test in other UI frameworks) examines a single widget. A widget test ensures that the Widget's UI appears and behaves as intended. A test environment that provides the proper widget lifecycle context is required for testing a widget, which involves numerous classes.The Widget under test, for example, should be able to accept and respond to user actions and events and conduct layout and instantiate child widgets. As a result, a widget test is more complete than a unit test. Like a unit test, a widget test replaces the environment with a more straightforward implementation than a full-fledged UI system.
  3. Integration Testing: After unit testing, integration testing is the next step in the software testing process. Units or individual components of the software are tested in a group during this testing. The integration testing level focuses on exposing faults that occur during the interaction of integrated components or units.
  4. Continuous Integration Testing: When a code change is noticed, Continuous Integration services allow you to run tests automatically. This gives you immediate feedback on if the code changes are working as planned and haven't introduced any errors.

Unit Testing

Unit testing's primary goal is to separate written code to test and verify if it works as intended. Unit testing is a crucial phase in the development process because, if done correctly, it may assist uncover early faults in code that would otherwise be difficult to find in later stages of testing.
Test-driven development (TDD) is a practical technique that takes a thorough approach to produce a product through continuous testing and modification. Unit testing is a component of TDD. This testing approach is also the initial level of software testing and comes before other types like integration testing. Unit tests ensure that a unit does not rely on external code or functionalities. Testing can be done by hand, but it's more common to automate it.

Widget Testing

To test widgets, the Flutter testing framework includes the testWidgets function. It accepts two views.

  • Test Description
  • Test Code
testWidgets(‘test description: find a widget’, ‘<test code>’);

Steps involved

  • In the testing environment, render the Widget.
  • WidgetTester is a Flutter testing framework class that builds and displays widgets. The WidgetTester class's pumpWidget function accepts any widget and renders it in the testing environment.
testWidgets('finds a specific instance', (WidgetTester tester) async { 
await tester.pumpWidget(MaterialApp(
home: Scaffold(
body: Text('Hello'),
  • It is locating the Widget that has to be tested.
  • Finders are among the numerous choices the Flutter framework provides for finding widgets presented in the testing environment. Find.text, find.byKey, and find.byWidget are the most often used finders.
  • find.text locates the widget containing the provided text.}find.text('Hello')
  • find.byKey locates the Widget using its unique key.
  • find.byWidget is a method for locating a widget based on its instance variable.
  • Ascertaining that the Widget performs as intended.
  • Matchers are among the numerous options the Flutter framework provides for matching the Widget with the intended Widget. We can use the testing framework's expect function to match the Widget we discovered in the second phase with our expected Widget by selecting one of the matches. The following are some of the most critical matches.
  • findsOneWidget checks that only one Widget has been discovered.

Integration Testing

Unit testing employs modules for testing purposes, whereas integration testing combines and tests these components. The software is made up of a variety of software modules that various programmers or coders have created. Integration testing aims to ensure that all components are communicating correctly.

Integration testing may be divided into two categories: manual and automated. 

Integration Testing of Units and Components.

The interactions and interfaces between integrated units/components are the subjects of this form of integration testing. After unit testing, unit integration testing is carried out, which is usually automated. Unit integration tests are frequently part of the continuous integration process in iterative and incremental development.

Integration Testing of the System 

The interactions and interfaces between systems focus on this sort of integration testing (A system is a group of interacting or interrelated entities that form a unified whole). The other system to be merged with might be either internal or external (developed by someone else over which the organization has no control). An Application Programming Interface (API) or a web service is typically used to expose such systems.

Continuous Integration Testing

The technique of creating a new version of your program every time you submit a change is known as continuous integration (CI). CI significantly influences testing since it ensures that stable software is never tested. The adjustments you're trying, on the other hand, are substantially minor. As a result, you'll need to take a different approach to tests than you did before. 

The shortcomings in this technique are evident. Various methods were employed in an attempt to enhance the procedure. Large chunks of software, for example, would be split down into little modules and handled as black boxes. Interdependencies were deleted as long as the interface operated. However, this will only go so far in resolving the problem. As a result, we arrive at continuous integration.

Frequently Asked Questions

What is a flutter app?

Flutter is a Google user interface toolkit that lets you build beautiful native mobile, web, and desktop apps from a single codebase.

How many testing steps are there to test a flutter application?

Three sorts of testing techniques may be used to test an application thoroughly. The simplest way to test an application is to use unit testing. Widget testing is the second step. To test widgets, the Flutter testing framework includes the testWidgets function. There are three steps involved. In the testing environment, render the Widget.

What is automated testing in the Flutter framework?

The Flutter framework provides strong support for automated application testing. Automated testing is divided into three forms to test an application thoroughly. It is the most straightforward approach to evaluating an application or piece of software.


In this article, we have extensively worked on Flutter app testing. We have briefly introduced the topic. We also explained the different types of testing. We also explained widget testing in a detailed manner along with its steps.

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