What is Android Testing: Types, Tools, and Best Practices

Android is the world’s most popular operating system, with over 2.5 billion active users in 190 countries. It is developed by Andy Rubin as an open-source alternative to iPhone and Palm OS, became the most popular mobile operating system in the early 2010s.

Android is the leading platform in the majority of countries, but has struggled to overcome Apple in Japan and the United States. In nations such as Brazil, India, Indonesia, Iran, and Turkey, its market share exceeds 85 percent. 

Global Market Share of the Android OS

However, with such popularity comes the challenges of Android Device Fragmentation. Device fragmentation in Android refers to the market’s abundance of Android smartphones with varying screen sizes, resolutions, hardware combinations, and software versions. This presents a difficulty for Android developers, who must verify that their applications are compatible with a broad variety of devices, which may be a time-consuming and difficult endeavour.

The user experience of an Android application may be significantly impacted by device fragmentation. If an application is not optimised for a particular device, it may not perform correctly or appear attractive on that device. For instance, an application intended for a larger screen may not be user-friendly on a smaller screen, and an application designed for a certain Android version may not be compatible with an older version.

Android developers can utilise a variety of strategies, including:

In order to assure compatibility, developers can test their programs on a wide variety of devices.

• With responsive design strategies, developers can ensure that their applications are optimised for various screen sizes and resolutions.
• With adaptive layouts, developers can modify the layout of an application dependent on the screen size of the device.
• With compatibility libraries, developers may ensure their applications are compatible with previous Android versions.
• With feature detection, developers may determine if a given feature is accessible on a device and alter the behaviour of the program accordingly.

However, of all these strategies, the most vital is Android Testing which ensures that the application works seamlessly across any and all devices.

Pro Tip : The only way to guarantee app speed and stability in the age of device fragmentation is to test them on actual Android devices. Given that hundreds of them are in use around the world, this presents a dilemma. Unless a company has enough finances to spare, it will be unable to build, operate, and improve an Android device lab on-site. In contrast, developers and testers can conduct tests on a real device cloud. 

In essence, it enables businesses to evaluate app performance and efficacy on actual Android devices without the need to gather or manage devices. BrowserStack provides the infrastructure in the cloud that enables android testing activities. Also, they can test websites on real browsers installed on Android smartphones. Testers can undertake Android testing by registering for free and selecting the desired device-Android version combination.

What is Android and How does it work?

Android is a mobile operating system designed specifically for smartphones and tablets. It was developed by Google and distributed for the first time in 2008. Android is an open-source platform, meaning its source code is accessible to developers for modification and enhancement.

Android provides a mobile user interface that includes a home screen, notification centre, and app launcher. It also supports multitasking, allowing users to simultaneously run different apps. Android applications are written in Java and executed on the mobile-optimised Dalvik virtual computer.

Android’s ability to interface with Google services such as Google Maps, Google Drive, and Google Play is one of its defining characteristics. Google Play is the official app store for Android smartphones, allowing users to download and install a variety of programs, games, and other content.

In order to better understand how Android works it is important to have an idea of its Architecture

Android Architecture

• The hardware layer consists of the device’s actual components, such as the processor, memory, storage, display, camera, and sensors.
• The Linux kernel provides the operating system’s basic services, such as device drivers, memory management, and security. Moreover, it manages communication between hardware and software layers.
• Android runtime consists of the Dalvik virtual machine, which is in charge of executing Android applications. The Dalvik virtual machine is optimised for mobile devices and employs a just-in-time (JIT) compiler to enhance performance.
• The application framework provides developers with a collection of APIs and services for building Android applications. It contains services such as the Activity Manager, which maintains the application lifecycle, and the Content Provider, which enables applications to share data.
• Applications: Apps are written in Java and execute on the Dalvik virtual machine (VM). Applications for Android can be downloaded through the Google Play Store and other app shops.
• The user interface consists of the home screen, the app launcher, and the notification centre. It also comprises system programs such as the phone application, the messaging application, and the settings application.

What is Android Testing?

Android testing refers to the evaluation of Android applications’ functionality and performance. Android testing entails testing the application on various devices, operating systems, and under various settings to ensure that it functions as intended.

There are numerous Android testing types, including:

1. Unit Testing
2. Integration Testing
3. Functional Testing
4. UI Testing
5. Performance Testing
6. Security Testing

Overall, Android testing is a crucial step in the creation of Android applications, as it ensures that the applications function effectively and satisfy user expectations.

The different types of Android Testing will be explored in the next section in some detail.

Different Types of Android Testing

Some of the different types of Android Testing are enlisted below : 

• Unit Testing: This sort of testing involves validating the functionality of individual application components or modules.
• Integration Testing: This sort of testing examines the interaction between various components or modules of an application to ensure that they function correctly when integrated.
• Functional Testing: This sort of testing entails verifying that the functionality of the application satisfies the requirements and specifications.
• UI Testing: This form of testing entails evaluating the user interface of a program to ensure that it is intuitive and user-friendly.
• Performance Testing: This sort of testing examines the performance of the program under various scenarios to guarantee that it operates well and does not crash or become sluggish.
• Security Testing: This sort of testing examines the application for security flaws and ensures that sensitive data is safeguarded.

While these divisions are all relevant it is important to look at Android Testing from a Test Pyramid perspective

Android Testing Types

Android Unit Testing

Unit tests are used to test the business logic, which does not use any android components like context, activity, etc., hence a physical device or emulator is not required to execute unit tests.

Unit tests are minimal and execute quickly in part because they lack platform-specific dependencies. Often, they concentrate on a single component, such as a function or class. This essay will focus on unit testing using JUnit4.

JUnit is a “Unit Testing” framework for Java applications that is already included into android studio by default. It is a framework for automating Unit and UI Testing. It includes annotations such as @Test, @Before, and @After, among others. To maintain the readability of this essay, we shall simply employ @Test annotations.

Step 1: Create a new Project

Create a new project by selecting File > New > New Project from the main menu in Android Studio to create a new project in Android Studio. Ensure that Kotlin should be selected as the programming language.

Step 2: Add dependency to the build.gradle file and click “sync now”

Step 3: Working with the RegistrationUtil.kt file

Construct a new RegistrationUtil file in Kotlin with an object type. Since this is a singleton, we do not need to construct an instance of it in other classes. isvalidRegistrationInput is a function that requires three arguments: username, password, and confirm password. Using the following test cases, we will evaluate this function using various inputs.

• Username, password, and confirm password cannot be left blank.
• Minimum password length is two digits.
• Password is equivalent to the confirmed password.
• Username must not be allocated to another user previously.

object RegistrationUtil {

private val existingUsers = listOf("John", "Jane", "Michael")

/**
* Checks if the registration input is valid.
*
* @param username The username to be checked.
* @param userPassword The password to be checked.
* @param confirmedPassword The confirmation of the password.
*
* @return True if the input is valid, otherwise false.
*/
fun isValidRegistrationInput(username: String, userPassword: String, confirmedPassword: String): Boolean {
// Check if username, password, or confirmPassword is empty
if (username.isEmpty() || userPassword.isEmpty() || confirmedPassword.isEmpty()) {
return false
}

// Check if username exists in the existingUsers list
if (username in existingUsers) {
return false
}

// Check if password matches confirmPassword
if (userPassword != confirmedPassword) {
return false
}

// Check if the password contains at least 4 digits
if (userPassword.count { it.isDigit() } < 4) {
return false
}

// All conditions passed, registration input is valid
return true
}
}

Step 4: Create a test class

To build a RegistrationUtil test class, right-click on RegistrationUtil, choose generate, and then select the test. A dialogue box will appear; select Testing library as JUnit4 and leave the class name as RegistrationUtilTest, then click OK.

Step 5: Write the Unit test code

Navigate to the file RegistrationUtilTest.kt and add the following code. The purpose of adding comments within the code is to make the code more comprehensible.

import com.google.common.truth.Truth.assertThat
import org.junit.Test

class RegistrationUtilTest {
   @Test
    fun `empty username returns false`() {
        val result = RegistrationUtil.isValidRegistrationInput("", "123", "123")
        assertThat(result).isFalse()
    }
    @Test
    fun `username and correctly repeated password returns true`() {
        val result = RegistrationUtil.isValidRegistrationInput("Test User", "123", "123")
        assertThat(result).isTrue()
    }
    @Test
    fun `username already taken returns false`() {
        val result = RegistrationUtil.isValidRegistrationInput("John", "123", "123")
        assertThat(result).isFalse()
    }
    @Test
    fun `incorrect confirm password returns false`() {
        val result = RegistrationUtil.isValidRegistrationInput("Test User", "123", "1234")
        assertThat(result).isFalse()
    }
    @Test
    fun `less than four digit password returns false`() {
        val result = RegistrationUtil.isValidRegistrationInput("Test User", "123", "123")
        assertThat(result).isFalse()
    }
    @Test
    fun `valid registration input returns true`() {
        val result = RegistrationUtil.isValidRegistrationInput("New User", "12345", "12345")
        assertThat(result).isTrue()
    }
}

Step 6: Execute the test cases

To run the test case, select Run RegistrationUtilTest by clicking the small run button next to the class name. If all test cases pass, the Run console will display a green checkmark. In our situation, every test passed.

Android Integration Testing

You should run these tests on a genuine device rather than a local computer. They are intended to verify that the integration between various modules or components is successful. These tests are typically medium-sized and should account for roughly 20% of the overall number of tests developed for your application.

With Android, a simple integration test might consist of determining whether tapping a button for a specific Activity leads to a different Activity. Because these tests run on a real device or emulator, they are often much slower than unit tests, therefore you should run them far less frequently.

Android End To End Testing

You will only write a couple of these tests for your application. Around ten percent of your entire tests should be end-to-end testing. As the name suggests, these tests are used to examine the entire user flow, from start to finish.

A multistep user registration flow is an example of a use case for which you would want to create an end-to-end test. As with integration tests, these tests must execute on a real device or an emulator. This implies that they will be slower, therefore you should run them fewer frequently.

These tests have a considerably greater level of fidelity because they imitate a real-world use case on actual hardware (if you’re using a real device for testing). Yet, if the test fails, it can be difficult to determine what went wrong due to the test’s need to examine so many moving pieces.

Why is Android Testing Important?

According to Statcounter, even though Android 10.0 is the newest and most popular version, obsolete versions such as 4.4 and 5.1 are still in use.

Android Version Usage Globally

These obsolete versions may not support some mobile functions and applications. The older devices also have differing screen resolutions, necessitating the categorical design of certain functionalities. Due to the vast number of Android applications available on the market, a typical user has a variety of options. If we are to keep our current customer base and attract new customers, our applications must function without error.

Android development, in contrast to iOS development, necessitates proper standards and various performance and optimization benchmarks. Why? Because the iOS device lineup is clean, gradual, and progressive in terms of capability enhancements. This is the phase that demands for rigorous Android development testing.

Android development testing is essential for ensuring app compatibility across a broad variety of device ecosystems and for app users to utilise the app to its maximum.

Android testing is a crucial component of the mobile app development process, as it ensures that the app functions as intended across a variety of devices and operating systems. Listed below are few reasons why Android testing is so crucial:

1. Quality Assurance: Testing ensures the app’s quality by discovering faults and defects early in the development process, hence reducing the cost and time required to rectify them later.
2. User Experience: Testing ensures that the application is intuitive, functional, and offers a great user experience. This can boost user retention and engagement.
3. Compatibility: Android testing ensures that the app is compatible with a variety of devices and operating systems, hence expanding the app’s potential audience and user base.
4. Security: Testing helps detect security flaws and concerns that could put consumers’ data at risk. This can help secure users and avoid data breaches.

A badly tested app can be detrimental to the developer’s or company’s reputation. Testing ensures that the application satisfies the quality and performance expectations of users. Thus, Android testing is vital for the development of high-quality, secure, and functioning mobile applications that give a great user experience across a variety of devices and operating systems.

Popular Android Testing Tools and Frameworks

It is necessary to be familiar with the available tools and frameworks, understand when to use them, and, most importantly, understand how to utilise them. QA professionals will only find testing tough if they are unaware of all the available tools or do not know how to utilise them.

Some of the most popular tools and frameworks are discussed below:

1. Appium 

Appium is a popular open-source application testing tool. It is a flexible cross-platform testing framework that allows QAs to develop test scripts for multiple platforms, including iOS, Windows, and Android, using the same API.

Hence, QAs can utilize the same code for iOS and Android, saving considerable time and effort. Appium permits testers to develop test scripts in many programming languages, including Java, JavaScript, PHP, Ruby, Python, and C#.

Appium Grid permits the parallel execution of Appium tests.

2. Selendroid

Selendroid is used for testing Android applications and is built on the Selenium framework. Selendroid may be used on Android emulators and actual devices to power the UI of native and hybrid apps. Selendroid, like Selenium, provides playback and recording capabilities.

Selendroid is also compatible with more frameworks, like JUnit. It provides cross-platform support via script export options for languages such as Java, Python, and Ruby.

3. Calabash

Calabash is an open-source mobile testing framework that supports many programming languages, including Java, Ruby,.NET, etc., to test native and hybrid applications.

Using Calabash, testers can create and run automated acceptance tests for mobile applications. It allows gestures like swiping, screen rotation, tapping, etc. It is compatible with the Cucumber framework. So, easier for non-technical stakeholders to comprehend and support Behaviour Driven Development (BDD).

4. Espresso

Espresso is an open-source UI testing tool for mobile applications. Google developed this testing framework for Android. It is renowned for its durability, simplicity, and adaptability. Its primary characteristics include Synchronized test executions, intent validations, and the ability to execute recipes.

Espresso permits developers to test both native Android views and hybrid web views. It supports Java and Kotlin test scripts. During development cycles, Espresso allows both black-box testing and testing of individual components.

5. Mockito 

Unit tests are designed to test a single unit of code in isolation from its dependencies. You don’t really care if a piece of code’s dependencies function well during unit testing, as you must test them individually anyhow.

Occasionally, though, it is impossible to test code without data from another section of the program. Consequently, to make unit testing practicable, the dependencies must be “mocked” out. Here is where Mockito enters the picture. This incredible framework provides a very easy and fluent API for easily creating mock objects. To test interactions, you can stub the state of a method or construct mock objects.

Best Practices for Android Testing

Here are some of the best practices for an effective Android Testing:

• Take steps to  create the appropriate expectations for teams, it is necessary to comprehend and establish a testing scope that is achievable.
• Choose the appropriate framework based on the needs of teams. Depending on the needs of the project, the preceding list assists in deciding when to employ each. Several teams make the error of selecting a popular tool that may not meet their needs.
• Test on actual Android devices, considering that many manufacturers release new smartphones with unique setups each year. Emulators and simulators are incapable of accurately simulating real user situations on Android smartphones. They are incapable of simulating a low battery, incoming calls, or a poor internet connection, therefore testing conducted on them would be highly inconclusive. Use BrowserStack’s real device cloud to automate Android app testing on thousands of actual Android devices (phones and tablets). Use actual hardware and software in your automated app testing to detect flaws before your users do.
• Set scripting rules. Consistent scripting, coupled with user comments and code indentation, plays an important role, especially given the frequency with which Android makes OS changes. Teams must update test cases to accommodate these modifications.
• Assess the impact of test automation by monitoring execution time, pass rate, test coverage, build stability, and other test automation parameters.
• Avoid comparing automation testing with manual testing, as each perform distinct roles in the development life cycle.
• Be sure to have vigilant Android App Debugging. This can be accomplished by thorough test reporting and debugging with screenshots, video, and text logs.

Conclusion

Android’s 71% market penetration necessitates a rigorous testing procedure for Android applications. The automation of their testing methodology enables teams to expand their device coverage. Several tools and frameworks for app automation testing are available on the market. Testing teams must meticulously select the appropriate structure and tools, and create the proper expectations for engineering teams.

In addition, it is advised to replace apk emulators with real Android devices in order to test under real user conditions and obtain realistic test results. Using a real device cloud like BrowserStack you’ll have access to hundreds of popular mobile device-operating system combinations such as Samsung Galaxy (S4 -S22), Google Pixel, and Xiaomi devices for testing their application and script automation instances. 

BrowserStack App Automate, you can integrate Appium and Espresso Automation Testing to run automated tests of your Android applications on real android devices.

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