Visual Testing for Native Mobile Apps: iOS and Android

In the mobile-first world, delivering a smooth and visually appealing user experience is supreme. Native mobile apps for Android and iOS platforms depend immensely on intuitive design and perfect functionality to delight customers and stand out in a global marketplace. However, ensuring the visual consistency and integrity of these applications across diverse operating systems and devices can be an arduous task. Fortunately, help comes from so-called visual testing appears as a game-changer in mobile app testing, providing an all-inclusive solution to validate the layout and appearance of native mobile apps on Android and iOS platforms. We took a closer look at the advantages of automated testing and visual tests and their importance in mobile applications.

On the market revenue front:

• According to Grand View Research, the international mobile app market size was valued at US$ 228.98 billion in the year 2023 and is projected to hit at a CAGR of 14.3 percent from 2024 to 2030. 

Source

• Emizentech Research Department, Android, and iOS application return hit $111 billion in the year 2020, marking a 24 percent y-o-y increase. Observing the mobile application download stats, the no. of mobile application downloads from 218 billion in 2020 hit 257 billion by the year 2023. 

Source

The mobile app sector is increasing by leaps and bounds, generating billions of dollars thus, it comes as no surprise that application testing is making unexpected records in terms of revenue. 

Why is visual testing significant for native mobile apps on Android and iOS?

Visual testing is critical for native mobile apps on Android and iOS platforms for numerous reasons:

1. Detection of Visual Defects: Visual testing helps discover various visual flaws, such as color discrepancies, inconsistencies, layout alignment issues, and graphical artifacts, which might not be apparent through functional tests alone. By detecting and addressing these bugs early in the app development procedure, visual testing helps prevent glitches from reaching end-users.
2. Stick to Design Guidelines: Android and iOS platforms have different design guidelines and User Interface conventions. Visual tests ensure that the application's design sticks to these guidelines, offering users a familiar and intuitive interface that aligns with their platform prospects.
3. Consistency across Platforms: Native mobile applications often require to maintain consistent visual elements, such as layout, styling, and graphical assets, across both iOS and Android platforms. Visual testing confirms that these elements remain consistent, irrespective of the underlying device model, screen size, or operating system.
4. User Experience Optimization: The impact of visual effects on any app greatly influences the user experience. The visual test helps detect any intricacies or bugs in the visual appearance, thus certifying that the users receive a smooth experience, which is crucial for user retention and satisfaction.  
5. Responsive Design Validation: Mobile applications often include responsive design principles to adapt their content and layout based on the device's screen size and orientation. Visual test substantiates that the app’s User Interface elements respond appropriately to diverse viewport sizes, confirming a consistent and user-friendly experience across a series of devices. 
6. Localization & Internationalization: Mobile apps might be required to support numerous locales and languages, which can introduce extra intricacies concerning text length, layout, and graphical assets. 

Challenges in Visual Testing for Native Mobile Apps

1. Device Fragmentation: With a plethora of gadget models, resolutions, screen sizes, and operating system versions, confirming consistent visual rendering across each device poses a major challenge.
2. Platform-centric Design Guidelines: Android and iOS platforms have different design guidelines and User Interface conventions. Ensuring sticking to such guidelines while managing a consistent brand identity requires scrupulous attention to detail.
3. Responsive Design and Dynamic Content: Native mobile applications often feature responsive design components and dynamic content. Certifying the responsiveness of the application's layout across diverse screen sizes and orientations is crucial for a consistent user experience.
4. Localization and Internationalization: Supporting numerous languages and locales introduces added complexities in visual tests, as text layout and length might vary based on the language used.

Executing Visual Testing for Native Mobile Apps

1. Selecting the Right Tools: Select the right visual testing tools that support native mobile application testing on both Android and iOS platforms mainly Cloud-based tools.
2. Creating Baseline Images: Establish baseline images for every application screen to serve as a reference for comparison during visual testing.
3. Automating Visual Tests: Leverage automated testing frameworks, such as Espresso or Appium, to automate visual tests and guarantee consistent test coverage across multiple devices and scenarios.
4. Integrating visual testing into continuous integration and continuous deployment Pipelines: Incorporate visual testing into the CI/CD pipeline to allow automated testing and timely feedback on visual alterations.

Steps of Visual Testing for Mobile Applications

Here are the following steps to run visual testing for mobile applications:

1. Detect the scope of the test: What visual facets of the mobile application do you require to test? This could consist of the typography, layout, images, colors, and animations.
2. Choose a test method: Automated or Manual visual testing? Manual tеsting encompasses visually examining the application on a series of devices & screen sizes. Automated visual test uses frameworks or tools to create screenshots and compare them to baseline images. 
3. Set up your test environ: This includes having the required devices, OSs, and test tools.
4. Generate a baseline image: This is a series of reference images that denote the projected visual appearance of your mobile application. You can generate a baseline manually or by utilizing automated visual testing tools.
5. Run your testing: This involves interacting with your mobile application and comparing the actual visual appearance to the baseline image.
6. Scrutinize the outcomes: Detect any visual dissimilarities between the actual and anticipated screenshots of your mobile application.
7. Fix visual errors: Once you have detected visual dissimilarities, you can work with your software development team to fix them.

Manual or Automated Mobile Visual Testing – Which to Choose?

Depending on Manual visual tests, can be quite prone to bugs and time-consuming. It includes QA testers checking the User Interface for irregularities or defects, a task that’s susceptible and subjective to human error, causing QA Engineers to overlook problems, introducing quality challenges, and reducing the test process.

As the app grows in intricacy, manual testing becomes highly sluggish and challenging, causing potential delays in the delivery timeline. Switching to automated visual tests can еasе up the complete mobile app testing procedure and the challenges linked with manual visual tests for mobile applications. 

Automated visual test tools have the capacity to capture and compare screenshots, pinpoint visual mismatches, log and report flaws, and implement testing repeatedly without the requirement for extra manual intervention. This approach excels at identifying even the minute visual variances that may go unnoticed during manual mobile visual tests—adopting an automated visual test not just saves time but also improves effectiveness, contributing to a complete improvement in the mobile test process.

How does visual testing benefit the development procedure for native mobile applications?

Visual testing proffers multiple benefits to the development procedure for native mobile applications:

1. Early Detection of Visual Flaws: By catching visual discrepancies during software development, QA teams can prevent them from reaching production and guarantee a polished user experience.
2. Improved Collaboration: Visual test fosters collaboration between developers, designers, and QA testers. Thus, resulting in better-coordinated efforts and smooth development iterations.
3. Better User Experience: By delivering a visually polished and faultless user experience, native mobile applications can attract and retain users, driving acceptance and success.
4. Streamlined Development Process: By automating recurring tasks, teams can focus on higher-value deeds, accelerate release cycles, and enhance overall productivity.
5. Increased Confidence in Releases: This type of testing also provides developers and stakeholders with confidence in the reliability and quality of each application release. 

How to Automate Visual Testing for Mobile Apps on the Cloud?

Cloud-based testing solutions like LambdaTеst offer AI-centered Smart UI testing platform, revolutionizing the identification of visual UI regression errors. 

What truly distinguishes LambdaTеst is its versatility in backup automated visual testing with mobile application test framеworks, including Appium on a scalable mobile device lab of real iOS and Android devices. This flexibility expands to multiple programming languages, including Nodе.js, Java, and C#.

To get started with Smart UI testing on LambdaTest, follow these steps:

1. Sign up and create your LambdaTest account.
2. Once you are in, browse the Dashboard, and navigate to Smart User Interface from the left menu.

3. Click on New Project. Pick the platform as Real Devices in order to run your automated testing. Provide project-centric descriptions such as Project Namе, Add Approvеr(s), & Add Tags.

4. Next, click on Create Project to generate your Smart UI Projеct.

5. Upload your iOS (.ipa) or Android (.apk) app to LambdaTest servers using the REST API. Utilize the cURL command with your credentials and application file path from the system or the application URL.

cURL command (using app file from the system):

curl -u “YOUR_LAMBDATEST_USERNAME:YOUR_LAMBDATEST_ACCESS_KEY” -X POST “https://manual-api.lambdatest.com/app/upload/realDevice” -F “appFile=@”/Users/

cURL command (using app URL):

curl -u “YOUR_LAMBDATEST_USERNAME:YOUR_LAMBDATEST_ACCESS_KEY” -X POST “https://manual-api.lambdatest.c

6. Copy the Appium Node.js GitHub repository  and navigate to the code directory.

1. git clone https://github.com/LambdaTest/LT-appium-nodejs
2. cd LT-appium-nodejs

7. Fix your LambdaTest Access Key and Username in environment variables. To obtain your LambdaTest credentials, choose Account Settings > Password and Security.

Linux/macOS:

export LT_USERNAME=YOUR_USERNAME

export LT_ACCESS_KEY=YOUR_ACCESS_KEY

Windows:

set LT_USERNAME=YOUR_LAMBDATEST_USERNAME  

set LT_ACCESS_KEY=YOUR_LAMBDATEST_ACCESS_KEY

8. Try to configure your testing script with Appium Desired Competencies. You can create Appium abilities for your test script from the LambdaTest Automated Capabilities Generator.

let capabilities = {

    deviceName: "iPhone 12", // Configure your Device for appium test (Mandatory)

    platformName: "ios", // Configure your OS for appium test (Mandatory)

    platformVersion: "14", // Configure your OS Version for appium test (Mandatory)

    isRealMobile: true, // Configure if you want to test in a real device (Mandatory)

    app: "APP_URL", // Set your uploaded App URL for testing (Mandatory)

    visual: true, // Configure your Capture screenshot  for appium test (Mandatory)

    name: "testing app session ", // Name of the test for appium (Recommended)

    build: "Real Device App Build", // Name of the build for appium (Recommended)

    "smartUI.project": "<Your Project Name>", // Replace the name of the project with the new project name (Mandatory)

    "smartUI.build": "<Your Build Name>", // Replace the name of Build with the new Build name (Optional)

    "smartUI.baseline": false, // Enable if you want to update to a new baseline build (Optional)

};

// Connecting to the LambdaTest Appium Cloud Grid with Smart UI

let gridUrl =

    "https://" +

    "<Your Username>" +

    ":" +

    "<Your Access Key>" +

    `@mobile-hub.lambdatest.com/wd/hub`;

// Here is your Remote WebDrive Connection

let driver = await new webdriver.Builder()

    .usingServer(gridUrl)

    .withCapabilities(capabilities)

    .build();

let capabilities = {

    deviceName: "iPhone 12", // Configure your Device for appium test (Mandatory)

    platformName: "ios", // Configure your OS for appium test (Mandatory)

    platformVersion: "14", // Configure your OS Version for appium test (Mandatory)

    isRealMobile: true, // Configure if you want to test in a real device (Mandatory)

    app: "APP_URL", // Set your uploaded App URL for testing (Mandatory)

    visual: true, // Configure your Capture screenshot  for appium test (Mandatory)

    name: "testing app session ", // Name of the test for appium (Recommended)

    build: "Real Device App Build", // Name of the build for appium (Recommended)

    "smartUI.project": "<Your Project Name>", // Replace the name of the project with the new project name (Mandatory)

    "smartUI.build": "<Your Build Name>", // Replace the name of Build with the new Build name (Optional)

    "smartUI.baseline": false, // Enable if you want to update to a new baseline build (Optional)

};

// Connecting to the LambdaTest Appium Cloud Grid with Smart UI

let gridUrl =

    "https://" +

    "<Your Username>" +

    ":" +

    "<Your Access Key>" +

    `@mobile-hub.lambdatest.com/wd/hub`;

// Here is your Remote WebDrive Connection

let driver = await new webdriver.Builder()

    .usingServer(gridUrl)

    .withCapabilities(capabilities)

    .build();

Make certain you have fixed the capability visual: true is set to capture screenshots.

9. Attach the subsequent web hook in the Appium script where you wish to take a screenshot.

driver.execute("smartui.takeScreenshot=<Name_of_your_screenshot>");

10. Contingent to your language or framework, you can implement your test suite. Here, in the case of Node.js, we execute the below command.

npm i && node your_test_script.js

11. To check your visual test outcomes, navigate to the LambdaTest Smart UI Dashboard.

Conclusion

Overall, visual testing plays a vital role in ensuring the consistency, quality, and usability of native mobile apps on iOS and Android platforms. Furthermore, integrating a cloud-based visual testing platform like LambdaTest takes it up a notch by tapping into the power of Artificial Intelligence. This dynamic duo not only intensifies effectiveness and quality but also brings intelligent insights, optimizing the complete test process for unparalleled results.