The role of Android emulators and iOS simulators in mobile application testing

Given how prevalent smartphones are today, mobile testing involves a huge list of devices that run on the two major mobile operating systems: Android and iOS. Operating systems have advanced over the years, but much of that advancement has been towards software features designed with smartphone hardware and mobile functionality in mind. Whether it's manual or automated testing, using virtual testing devices—emulators and simulators—plays a big role in assessing the mutual compatibility of native mobile applications.

Emulation and simulation explained

Running tests in virtual environments is an effective way to cover the majority of the software testing you need to perform on mobile applications, and not just because real device testing is prohibitively expensive. Setting up a virtual environment with the required hardware and software combination is key to achieving optimized testing.

Emulation and simulation are two ways of initializing virtual devices we call emulators and simulators. Emulation is the process of mimicking underlying hardware and software to perform actions within a guest system. Simulation is responsible for modelling the software system and dependencies to study its behavior as accurately as possible.

Emulator vs. simulator

Testers use emulators and simulators to replicate various devices to test mobile applications. Below are the key differences between them:

An overview of mobile testing

Let's discuss mobile application testing and its importance to understand how to use simulators and emulators for real devices. Whether they're native to iOS or Android platforms, mobile applications are deeply integrated with mobile device hardware. Modern mobile applications are developed to run on physical devices and are regularly assessed to determine whether they're performing all of their functions without deviating from projects' requirements.

Uses of mobile testing

Comprehensive mobile application testing helps testers identify anomalies associated with the following components of software functionality:

• User interface (UI) - Users expect applications to display UI elements accurately, with snappy responses to their interactions.
• Screen resolution - Different mobile devices feature different screen resolutions, and developed mobile applications should work flawlessly across hardware configurations.
• Features - To provide advanced functionalities, mobile application features are designed to take full advantage of the actual hardware available in mobile devices.
• Integrations - Modern applications rely heavily on integrations with third-party services for added functionality and for triggering workflows that facilitate advanced operations.
• Performance - Every mobile application's functionalities must work efficiently, continuously, across a multitude of real-world scenarios, and for a variety of end user personas.
• Security - Mobile applications require robust security, as even a single vulnerability can lead to a potential breach, which could put all of the user's personal data in the mobile phone at risk.
• Compatibility - If the mobile device meets the minimum technical requirements, irrespective of the hardware configuration, the application should work flawlessly for maximal adoption.
• User experience - Every aspect of the mobile application, including the prerequisites mentioned above as well as other criteria, contributes to the end user experience.

Today, there are hundreds of different mobile device models in use, if not thousands. Testers must assess the advanced functionalities of mobile applications across all of these device combinations, and virtual devices are the answer to these scenarios.

Why you should use virtual devices for mobile application testing

Software testing teams around the globe rely on virtual devices for mobile testing, irrespective of a project's size or complexity. Here are some reasons to use them instead of testing real devices:

• Cost-effective - Configuring a lab of real devices requires purchasing and setting up a physical infrastructure of iOS and Android mobile devices for testing, which is expensive.
• No degradation - Unlike real devices, which are susceptible to performance drops and obsolescence, time doesn't affect the performance and effectiveness of virtual devices.
• Ease of use - The different device combinations one must test to assess an application's compatibility need to be connected physically and in succession. However, since their underlying hardware is easily accessible, virtual devices don't require a complex process to run tests.
• Parallel testing - Performing parallel testing simultaneously across multiple virtual devices doesn't require any extra setup, whereas it's sometimes impossible to connect multiple real devices.
• Uninterrupted testing - Testing performed on simulators and emulators is not affected by cellular disruptions like incoming calls, notifications, and more—or the battery state of the test device.
• Reliability - Simulators and emulators are not mere reproductions, but replications that are as similar to real devices as possible. These virtual devices also support the advanced features and hardware capabilities of real devices.
• Continuous updates - Platforms that provide a collection of emulators or simulators continuously update the list of available testing devices as the latest actual devices are released in the market.

Mobile application testing using iOS simulators

Xcode, Apple's integrated development environment, features a simulator that's deeply integrated with macOS and features the latest iOS mobile devices. The availability of Apple's native Cocoa API ensures that the simulators work efficiently and are readily available for testing without requiring any initial setup—but only for macOS.

This simulated environment includes support for scrolling, multi-gesture taps, and everything else needed to interact with the installed iOS application. Virtual environments also support the replication of hardware button interactions, which is also helpful when it comes to testing an iOS application's behavior, especially in physical devices. An example of a good simulation is one that uses the power/lock button, which provides the opportunity to test the application when the phone is switched between the sleep/wake state.

Mobile application testing using Android emulators

There's a rich variety of third-party emulators available for Android devices, some of the most popular of which are Blustacks, NoxPlayer, and Genymotion. However, the officially recommended emulation software is Android Studio. Unlike Xcode, it works on both Windows and macOS platforms.

Software development kits available for Android applications natively support deep integrations with hardware and core system functionalities. Android apps need to be installed in emulators, as is the case with simulators. Emulators can take advantage of available customization options to test mobile applications in environments that are as similar to real devices as possible.

Apart from the usual navigation options, emulators provide hardware acceleration, just like the physical devices used in the real world. To test applications, emulators accurately emulate software environments and other components present in real devices. For example, these virtual devices can help assess an app's background memory management as though it's a real device.

Disadvantages of emulators and simulators for mobile testing

Even though the emulators and simulators provide a huge list of advantages and advanced features, there are a few disadvantages:

• Bandwidth usage - Generally, mobile devices rely on network data as opposed to WiFi or broadband connections, and checking mobile applications for data usage therefore isn't possible on virtual devices. Downloading assets or transferring data between services for communication consumes data; the role of testing is to optimize applications to use minimal data.
• Interface - The interfaces of virtual devices don't provide the same usability as those of real devices.
• Battery consumption - Testing on virtual devices doesn't account for real-world battery consumption, upon which other systems and tasks place demands.
• Debugging - While assessing an application's features in a virtual device is easy, but comprehensive testing and debugging requires the installation of extensions and third-party tools.
• Distractions - Real-life mobile application use is frequently interrupted by notifications, phone calls, messages, and other distractions. The ideal conditions testers observe in emulators and simulators often don't reflect real-world experiences. Interruptions and user behaviors can affect the performance of mobile applications.
• Usability testing - Usability testing constitutes the last leg of the entire testing phase. Even though the use of virtual devices is enough to improve coverage, checking applications on real devices provides more accurate user feedback that closely reflects the real world.

Can virtual devices be used for the entire testing process?

While testers can substitute real devices for virtual devices like simulators and emulators throughout most of the testing process, to get an accurate understanding of how their applications perform in the real world, they need to test their applications on real devices. Real device testing isn't constrained by the limitations of virtual environments when it comes to assessing software.

Mobile application testing with Zoho QEngine

Zoho QEngine enables developers to test mobile applications with simulators and emulators. QEngine's virtual testing devices accommodate advanced gestures to emulate user interactions, hardware acceleration for improved performance, and an accurate implementation of hardware buttons. These—as well as other features—combine to provide a software testing environment that can predict applications' behaviors in the hands of end users.

With Zoho QEngine, you can easily set up and perform mobile application testing in minutes by following a few simple steps:

1. Download and install Zoho QEngine’s local agent on your operating system(s).
2. Download and install the extension for your web browser(s) of choice.
3. Install a testing application.
   1. To access Android emulators, install and set up the latest version of Android Studio on Windows or macOS.
   2. To access iOS simulators, install Xcode on macOS.
4. Once Android Studio or Xcode are installed, configure the required emulators and simulators for use inside the local agent.

Use a no-code recorder, a low-code builder, or pro-code editor to write test cases for testing Android and iOS applications.