Top 20 Appium Interview Question & Answers

Freshers and entry-level professionals in Computer Science, Information Technology (IT), and related fields tend to be on a constant lookout for career advice and interview prep resources. This blog will discuss some of the most commonly-asked Appium interview questions during the hiring process for full-stack developers. 

We have covered a good mix of questions from beginner and intermediate levels to support you every step of the way! 

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Top 20 Appium Interview Questions & Answers

1. What is Appium? List its capabilities.

Appium is an automation framework used for testing mobile applications. Developers use this open-source tool to run scripts and test native, mobile web, and hybrid apps on Android or iOS. 

With Appium, you can:

• Support JSON wire protocol;
• Do away with recompilation of the app;
• Support automation test on physical device and emulators; and
• Use a web driver without depending on mobile devices.

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2. What are the different types of mobile app testing?

There are several types and approaches to mobile app testing. Some of them are:

• Functional Testing: Ensures that the flow, features, and purpose of the app operate correctly and meet the specifications.
• Usability Testing: Checks the user-friendliness and intuitiveness of the app with the view of improving customer experience. 
• Compatibility Testing: Non-functional testing done to examine whether the software works on different operating systems, devices, network environments, etc.
• Performance & Load Testing: Probes the performance of device, network, and API / server to reduce the risk of malfunctioning. 
• Security Testing: Tests device behaviour under various permission schemes to ensure the protection of users’ personal information. 
• Installation Testing: Inspects whether the app can be installed and uninstalled properly and that updates can happen without interruption and errors.
• Localisation Testing: Scrutinises that the app meets the local legal regulations and is accessible by a wide variety of markets.
• Manual Testing: Involves complex mechanisms and tests to explore use cases that may not be obvious in the first instance.
• Automated Testing: Uses a thoughtfully packaged framework to build and maintain test scripts and management of test runs. 

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3. How does a typical mobile testing framework function?

A standard mobile testing framework is divided into three segments, namely:

• Application Package: This is the target mobile app that requires testing.
• Test Case Runner: It is an instrumentation test-runner for the target app, containing an SDK tool (for building tests) and an API provider (for writing the program).
• Test Package: It has two classes, known as Test Case and Mock Objects. Tests Case classes comprise test methods, whereas the Mock Objects include mock data or sample inputs for the test cases.  

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4. Explain the Appium design concept.

The main components of the Appium architecture are:

• Appium Server: An HTTP-based server that responds by translating automation commands to a language understandable by Android devices.
• Appium Clients: A framework of clients that list the supported languages, such as Java and Python. 
• Appium Driver: The UIAutomator2 driver that supports mobile operating systems.

Node.js should be pre-installed before initialising the Appium Server. Upon downloading Appium, the REST API gets exposed and one receives the connection and command request from the client. This command can be executed on Android or iOs devices. The machine then gives HTTP responses, using automated mobile app testing tools to execute the request and drive the app’s user interface. 

5. Which languages can Appium support?

Appium supports those languages capable of supporting HTTP requests. These include Java, JavaScript, Node.js, Python, PHP, Ruby, Perl, among others. 

6. Do you need a server machine to run tests?

No. Appium facilitates a server-2 architecture that makes it possible to run tests without a server machine. The entire process is automated as the test machine connects to a test server on which Appium is running. This way, Appium can run on the same machine on which your test runs. 

7. What are some limitations of using Appium?

While Appium has many functionalities and advantages, there are some shortcomings to using this automated testing framework for mobile app testing. Here are some of them:

• It is not possible to test Android versions lower than 4.2. 
• The switching action of an app from the web to native and vice versa is tricky to navigate with Appium.
• You cannot run Appium Inspector on Microsoft Windows.

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8. What are the basic requirements for Appium test writing?

Driver Client, Appium Session, Desired Capabilities, and Driver Commands are the four must-haves for wrong Appium tests. These are described in detail below:

• Driver Client: Enables you to use the client library for writing your own tests, wrapping test steps, and sending over to HTTP. Appium drives the mobile app just like a user would.
• Appium Session: Tests occur in a particular session. Once the automation is done, you have to wait for another session to initialise Appium. 
• Desired Capabilities: PlatformName, DeviceName, and PlatformVersion are some examples of parameters that need to be defined to initialise an Appium session.
• Driver Commands: This is the extensive vocabulary of commands that is ultimately used to write tests.

9. What do you mean by an Appium Inspector?

Appium Inspector is similar to Selenium’s IDE record and Playback tools. While Selenium is an automation framework for web applications run on browsers, Appium is a suitable tool for apps that run on mobile devices. 

Appium Inspector can record and play native application’s behaviour by performing the following tasks:

• Inspecting DOM
• Locating element of the mobile app
• Generating test scripts in desired languages

10. Differentiate between Simulators and Emulators.

Simulation is concerned with modelling the underlying state of the target. In an ideal case, you can observe all original features in a simulation. On the other hand, emulation involves imitating the externally observable behaviour of the target. While the external state of the emulation matches the target, the same is not true for the internal properties.

Simulators and Emulators create room for running quick and easy tests inside flexible, software-defined environments without needing to set up a hardware device. 

11. Explain Locators with examples. 

One can identify the elements of a mobile application through some properties, some of which are standard in nature. The standard app properties are referred to as Locators, for example, ID, name, accessibilityID, className, XPATH, etc. 

12. Define XPATH and its use in locating elements.

You can navigate through the XML structure of any document with XPATH’s specific syntax. It is a string-based identifier that can reach any element. Appium has a ‘FindBy’ function that passes the XPATH string to return elements. 

13. How does FindElement differ from FindElements?

FindElement checks the availability of a specific element in the application UI screen. FindElements can locate multiple elements. 

Another difference between the two is that FindElement throws an exception upon not finding any element, but FindElements returns a 0 size array.

14. Mention some potential errors that you can encounter with Appium?

Errors can arise on account of:

• Not providing the Desired Capabilities like DeviceName, PlatformName, etc., when they are required.
• Forgetting to set the <ANDROID_HOME> environment variable with the SDK root directory path. The error could say, “Could not find or locate ADB.”
• Unrestricted querying and XPATH usage. The error indicates the failure to locate a DOM element or to find XPATH in a mobile application.

15. Define implicit and explicit wait in Appium.

On certain occasions when there is a delay in loading elements on the application screen, Appium provides the options of Implicit and Explicit Wait, which add a delay for a specified time and for specific conditions, respectively. 

16. How do you perform debugging with Appium? 

You can debug Appium tests using the underlying language or IDE of the platform. It is fairly easy to do so as Appium is a Node.js application and the code is freely available on GitHub. You can use Java Remote and also grasp the root cause of any issue using the server logs provided by Appium. For example, Monitor.bat (for Android) and iPhone configuration utility (for iOS) can help reveal why a failure has happened. 

17. Describe Data Exchange in the context of Appium.

Data Exchange refers to the trade of information in different parts of your review-based app, usually hosted by complex objects like the window object. Suppose you had to dispatch and capture events. In that scenario, your app would have to perform several functions and the information could flow in many ways. Some objects may have a state or the state machine in your app may be large, which may create problems while testing. So, data exchange is different from getting the value of a textbox or setting an element’s attribute. 

18. What are the risks of automation testing?

Automation testing requires some practical knowledge of programming. So, the inability to find or hire skilled resources in your team is a high-priority issue. The high cost of initial setup, training, and maintenance associated with automation tools poses another concern. The cost for script maintenance can become exorbitant if the UI is not fixed.

19. What are the prerequisites for automation testing?

First and foremost, you have to segregate the test cases that you want to automate. Depending on your needs, you prepare the test data and write reusable functions that would be frequently used in your test cases. Then, you prepare the test scripts and apply loops and conditions as you go along. 

20. What are the pros and cons of using Appium?

Advantages of using Appium:

• All complexities remain under a single server irrespective of the platform.
• It enables cross-platform mobile testing.
• It does not require additional components to make the application automation-friendly.

Disadvantages of using Appium:

• Scripts can run on multiple iOS simulators at the same time.
• It uses UIAutomator that does not support older APIs 

This brings us to the end of our list of top Appium interview questions! 

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The above-mentioned Appium interview question and answers will help understand and strengthen the basics, whether you are a fresh computer science graduate or an IT professional. Having a good grasp of these fundamental concepts can lead to a stellar first impression!