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Emulators and Simulators vs. Real Devices For Automation

Emulators and Simulators vs Real Devices For Automation

In this article, we are going to go through testing mobile applications on emulators & simulators vs. on real devices 📱

Emulators and simulators are software tools that imitate various operating systems. Did you know search engines such as Google began prioritizing websites friendly to mobile over websites only rendering information via desktops?

As a result, it’s critical we resolve serious issues before releasing an application to the market. The fundamental testing principles are similar between mobile and desktop. However, the details are different with mobile.

Table of Contents

What Are Mobile Emulators and Simulators

A mobile emulator is a program that replicates the software and hardware of our system. It’s a program that copies the behavior of a real target device. However, emulators are set up in a virtual environment. By establishing a virtual environment, the software development team has access to end to end functional testing.

Some of the hardware components that can be tested include battery performance, random access memory (RAM), processor, camera, and keypad. The software includes components such as messaging, security, and browsing the web 🌐 Due to specifications on the phone, the emulator could fail to maintain a desirable pace if the website is massive.

A mobile simulator is a program created in a virtual environment that also copies the configuration and behavior of a real target device. It sounds very similar to a mobile emulator because both programs provide a comparable purpose. Often, the terms are used interchangeably but the difference revolves around the hardware.

Simulators do not mimic the hardware. Only emulators can test a feature like the microphone or speaker. A simulator is created to accommodate only softwares that exist in a mobile’s production environment.

Mobile Test Types

There are many mobile applications and multiple types of testing for those applications. The most common type is functional testing which confirms an application is working according to requirements. Other types include:

  • Compatibility Testing – checks if the mobile application is compatible with different operating systems and versions.
  • Installation Testing – checks if the installation and uninstallation process is effortless for the user. It also guarantees the updates are error free and investigates what happens when a user does not update a certain application.
  • Interruption Testing – checks the behavior of an application while in a suspended state then resuming to the previous state. For example, a user is watching a video and receives an incoming phone call. The video application should run in the background then resume to the previous state prior to the interrupted phone call.
  • Load Testing – checks how an application responds when many user access the application at the same time. The users attempt to install, uninstall, and use an application simultaneously to see if it crashes or has slow load times.
  • Localization Testing – checks the quality of being responsive to a certain geographic region. For example, the test may include verifying a specific language, local regulation requirements, or time zone.
  • Performance Testing – checks the performance under specific workload conditions such as reviewing the speed of an application, bad network coverage, and low available memory.
  • Security Testing – checks vulnerability to authentication, authorization, hacking, and data security.
  • Usability Testing – checks if users have positive feedback. The goal is to verify whether the application is easy to accomplish a particular objective.

Mobile Automation Testing Tools/Frameworks

Automation tools are part of a blazing trend for mobile 📈 A few reasons include fast feedback, CI/CD, more accurate test, and maximized productivity. Here’s a list of some technology leading tools:

  • AppiumAppium is an open source automation framework for testing native, hybrid, and mobile applications.
  • TestProjectTestProject is a free test automation platform for mobile (Android & iOS), web, and API testing.
  • DetoxDetox is an open source end to end testing framework which runs on a real device or simulator.
  • EspressoEspresso is a native framework for testing Android applications.
  • XCUITestXCUITest is a testing framework for iOS applications.

When To Use Emulators & Simulators vs. Real Devices

There are strengths to using emulators, simulators, and real devices. The testing route we choose depends on an application’s risk and phase. For example, if the only risk is rendering a website, then it’s best to choose an emulator or simulator.

Both are sufficient if responsiveness is the objective for an end-user 👩‍💻 In addition, the cost is much favorable compared to using a real device. However, some defects can only be caught by using a real device. So if the main risk involves actually swiping and dragging an application, it’s probably best to not choose an emulator or simulator.

Organizations prefer to only use real devices, but they are costly. Therefore, the ambition is to use a combination of emulators, simulators, and real devices. A rule of thumb is to use emulators for testing hardware and simulators for testing software. An emulator can check how our application operates using different CPU’s or different memory allocations.

A good example is testing firmware using an emulator. Firmware is everywhere on our phone. It’s software that supplies a low-level oversight for the mobile’s hardware.

The simulator can ensure that an internal application performs strongly when interacting with an external application, such as sending data between applications. Emulators and simulators are helpful when testing across an extensive range of conditions.

In spite of that, it’s beneficial when they are not replacements for real devices. Testing on a real device serves a great use when applied at important points before production. The testing phases should escalate with emulators, simulators, and real devices.

The closer we get to production, our choice between each option steps up. An organization can utilize a virtual platform in the early phase, that involves development cycles. Unit testing and smoke testing are performed because developers isolate units of their code.


Emulators and simulators assist with providing fast feedback. Since real devices are expensive, they are retained for later phases such as integration testing and functional testing that’s designed for specific types of test ✅

About the author

Rex Jones II

Rex Jones II has a passion for sharing knowledge about testing software. His background is development but enjoys testing applications.

Rex is an author, trainer, consultant, and former Board of Director for User Group: Dallas / Fort Worth Mercury User Group (DFWMUG) and member of User Group: Dallas / Fort Worth Quality Assurance Association (DFWQAA). In addition, he is a Certified Software Tester Engineer (CSTE) and has a Test Management Approach (TMap) certification.

Recently, Rex created a social network that demonstrate automation videos. In addition to the social network, he has written 6 Programming / Automation books covering VBScript the programming language for QTP/UFT, Java, Selenium WebDriver, and TestNG.

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