UI Testing of Mobile Apps (iOS and Android UI Testing)

Mobile Apps UI Testing Guide: Learn how to perform iOS and Android UI Testing

With the flourishing market for mobiles, testing of mobile applications has become exciting day by day.

Just by running functional tests on a mobile application you cannot sign off the app. There few other testing as well like field testing, network testing, UI testing, battery life testing etc., that needs to be done apart from this. And UI testing is one of the important tests in mobile application testing and it should not be taken lightly.

UI Testing for mobile apps

As a user will you feel like using an app that lacks user interaction and makes it difficult to understand how to use it?

When the users use a mobile application for the first time, it’s not just the performance that steals the attention but also the appealing UI. A UI friendly application sells more when compared to an app which is best developed but with a nasty UI.

If an application has a perfect and a splendid UI on one device but on the other device it is completely twisted just because it has a different size or a different OS, then it will leave a very bad impression. The commercial success of the application will be badly affected.

Will you promote an app where the button is too small to click blocking the whole set of functionality?


Aren’t these unpleasant experiences for the users? Due to the above-mentioned cases, it becomes very important to test the UI of an application. The two major verification that needs to be done for mobile applications is user friendliness and appearance across different models and OS versions.

Following is an Example of how the UI should be perfect across different screen sizes:

UI Variation with phone size

How to Decide on how much UI Testing is Required?

The following chart denotes the various verticals in which mobile apps can be categorized:

Mobile App Verticals

[image source]

From the above chart, you can make out that Gaming apps take the majority of market share of about 24.43%, and then followed by business and education apps.

  • Apps developed as gaming apps need a thorough testing at each and every aspect as the UI is the biggest contributor to gain success no matter if it’s a Native or Hybrid app
  • A business app may not completely rely on the UI for its success because in most cases the target audiences are trained to use the app. Hence, such apps may have a simple UI.
  • Apps developed for educational purposes need a thorough UI testing.
  • Commercial apps like shopping, travel etc also need a complete UI testing across devices and various OS versions.

In short, depending on the purpose of the app, the depth of UI testing can be decided but UI testing should always be done on at least 3 different OS versions.

What Should be Tested in UI Testing for Mobile Applications?

While testing UI on a mobile application, there are various characteristics that need to be verified.

Following are some of the characteristics that should be tested for every app:

#1) Screen Resolution:

Following are some of the common screen resolutions that are considered while creating test beds:

  • 640 × 480
  • 800 × 600
  • 1024 × 768
  • 1280 × 800
  • 1366 × 768
  • 1400 × 900
  • 1680 × 1050

All of these resolutions are a must for testing when you have a multi-column layout in your app.

Hence verification needs to be done starting from the smallest to the biggest resolution. Apart from this, if your app has a long list of cards with information then those also need to be tested on a different resolution for their information wrapping.

UI multi column layout

UI card travel

[image source]

#2) Different UI Elements:

The UI elements like buttons, headings, icons, images, selection fields, text fields, checkboxes etc., are some of the different elements that need to be verified for their appearance and size on the screen.

Specifically for text fields, if the soft keyboard shows up on a tap in the text field should be tested and verified.

Most importantly a thorough testing of button sizes is required because I remember in our app while testing on Galaxy S phone, we found a blocker where a button had blocked the entire app just because the button appeared too tiny to click on.

The position of the UI elements should also be verified against the requirement i.e. if all are to be center-aligned or left-aligned etc.

#3) Color and Theme Scheme of the Device:

The app UI and color scheme should be consistent with different colors and theme schemes of the phone. The color and theme of a Samsung phone are very different from that of Nokia or a MI phone.

Hence you need to verify if the app is looking consistent across such phones.

#4) Multi-touch or Single touch:

If your app is supporting the multi-touch feature like pinch to zoom or pinch to shrink etc., then you need to thoroughly test this feature and create a lot of test cases for this for all the applicable screens.

#5) Long or Short Press:

A long press on an icon shows the context menu while a short touch performs the very first action of the menu. If this feature is provided in your app, then you need to verify this functionality and all the functionalities around it.

How to Test UI Variations across different OS Versions?

The UI varies with the OS version and with the launch of a new version, enhancements are made in the UI.

Let us observe the UI of the 3 latest OS that are currently available and understand how these variations affect a mobile application.

They are:

  1. Lollipop
  2. Marshmallow
  3. Nougat

UI variations

Looking at the above list of new UI or functionality features, as a QA you need to design test cases around this.

1) Lollipop:

  • Create test cases for the effect of the new design on your app.
  • Not necessarily for all the screens but create test cases for accessing the new shortcuts on your app.

2) Marshmallow:

  • If your app deals with emojis, create test cases to verify the new emojis. Apps which allow the users to write reviews or to chat are the ones which use emojis frequently.
  • When your app is published and installed for the first time, it may need to ask for permission hence the need for UI testing of the new permission screen needs to be done. And create test cases for the same.
  • If your app is using Google Now then you need to create test cases to test the updated Google Now feature’s UI.

3) Nougat:

  • A thorough testing of your app needs to be done for the daydream reality mode and hence create test cases accordingly.
  • Create test cases to verify the menu options for your app.
  • If your app deals with emojis and GIFs, then create test cases to verify the new emojis and the option to send GIFs.

Real Devices or Emulators: What to Choose for UI Testing?

When you have to test a mobile application you may think about what the test bed should be?

Whether to test on a real device or emulator or both? There’s no firm answer to this because the choice depends on what you want to test.

For testing the functionality, performance, network response, field test etc., you should always prefer a real device. But for things like UI you should choose emulators along with some real devices.


The pros of using emulators for UI testing are:

1) It is not practically possible to collect the devices of all resolutions and that would also cost an enormous amount of money. But emulators cost nothing.

2) With an emulator, you can create all screen resolution and OS combinations.

3) If you have only one set of real devices but the QA team is of more than 1 person, then it is not possible that all QAs can test for the same test bed in parallel. With an emulator, every QA can create the same combination on their machine and test in parallel.

4) Testing on an emulator is less time consuming and is faster when compared to a real device.

5) Common bugs related to the UI like alignment etc can be easily caught on emulators.


Cons include:

1) Gestures can’t be tested on emulators. Only one gesture can be emulated at a time.

2) Physical inputs of GPS, dropping or weak network etc also can’t be tested.

3) There is no way that you can create an emulator for Sony, LG, Nexus, etc phones.

4) It is not possible to create a real environment with a low battery or low memory etc., on the emulator.

Hence the decision should be made depending on your app and the testing requirement.

Is Manual UI Testing Feasible or should I Automate?

No product whether it a desktop app or web app or mobile app can be released without testing. As a QA we struggle to find and report each and every defect but still, they are reported by customers.

Do you know why?

Because lengthy tests that are often avoided or missed thus leaving undetected bugs. Also 100% coverage, in-depth execution is not possible with manual testing.

UI testing is pretty simple and straightforward and you just have to look at how it is appearing to your eye. Now if this is done manually it is very time-consuming. Also, most of the times we need to create a huge data for UI testing like a scroll will appear only if the rows or cards cross a particular count.

Creating big data is very time-consuming. Having an automated suite can solve both the problems.

On the contrary, if the functionalities or UI of the app are still in a changing phase then it doesn’t make sense to invest in automation. Similarly, if the functionalities of the app are vital, then it is better to test manually.

Hence depending on the following pointers, you should decide whether to test manually or to automate:

  • The nature of your app.
  • The stability of your app.
  • The resources available like manpower to study the tools and compare them.
  • How much time is invested study and ramp up of an automation tool that is required?
  • Is the client ready to invest time in the ramp-up and study?

Best Automation Tools for UI Testing

Following is a list of 5 tools that can be used for UI testing of a mobile application for Android and/or iOS.

(For functionality testing tools you can refer to the list of automation tools on our automation tools for testing Android applications page).

#1) Selendroid:

Selendroid is one of the best and most recommended tools for mobile application automation for UI testing.

It can be used for both Native and Hybrid apps. It can be used only for Android apps and the client API tests are written using Selendroid 2. It can also be used with more than one device and is fully compatible with JSON.

#2) Testdroid:

This is a cloud-based tool and can be used for a variety of devices, different screen resolutions and OS versions of both Android and iOS. Parallel device testing is a big advantage of this tool and is a good tool for UI testing. It helps the developers to improve the time-to-market.

#3) SeeTest:

It is a paid tool and can be used for Android, iOS, Windows, Symbian etc.

It is a cross-platform tool and hence the advantage is that same test can be run on all platforms. It can be used for all mobile applications and the tests can be run in parallel on more than one device.

#4) UI Automation:

This is the official UI testing tool of Apple and is the best tool for automating iOS applications. Although it is hard to learn, it offers a great advantage with libraries, performance, UI testing etc.

#5) Calabash:

It can be used for both Android and iOS testing for native or hybrid apps. It is a cross-platform tool and it is best used for automating gestures, screenshots, assertions etc. It can be used on real touchscreen devices. It also has support for cucumber.

When developers are unit testing the app, they can also do UI testing using Android Studio but it can only be used for Android applications, you can study more about it on developer.android.com.


All the mobile applications need a UI testing but the deepness of testing required is defined by the category or purpose of the application. You should do a complete analysis of the application’s UI features against the phone’s model or OS versions before you finalize your test bed.

Based on this analysis, you should create your test cases for testing. Use automation wherever possible to save your time.

Keep an open eye while testing the UI because it is simple yet it has a big effect on the selling of your app.

Take a look at our upcoming tutorial for detailed information on Mobile Responsive Test.