Testing on Emulators vs Simulators vs Real Devices
By Akshay Pai, Community Contributor and Pradeep Krishnakumar, Manager - June 20, 2019
Web Testing and App Testing has always been an important part of the overall development process. Testing involves finding and solving bugs – be it identifying glitches in navigation, issues with signup forms, breaks in payment processing or just a simple difference in font size. However, testing can ensure that every change does not break the user experience across different devices.
A key part of having a robust testing process is the devices on which the test is being run. A thorough testing procedure can also generate a variance in its results when performed on different devices. Thus, the significance of the testing device is paramount. The significance is even greater for testing on mobile devices, given the variety of devices, with different operating systems, browsers and hardware configuration.
To get a deeper understanding, let us study the different mobile testing device solutions.
Types of Mobile Testing Device Solutions
As the technology has evolved with time, testing too saw its share of advancements in the form of various mobile testing device solutions that emerged. These mobile testing solutions were built in order to support cross browser testing of websites and mobile app testing on different mobile phones by analyzing the application’s behavior, function and UI aspects.
The prime reason for this kind of testing is to ensure consistent behavior of the website and app on different mobile devices. Since these devices differ by hardware configuration, operating system and screen resolution, what might work in a certain way on one of the devices could vary for the other.
There are mainly two types of devices on which mobile testing is conducted:
- Real Devices
- Virtual Devices
What is a Real Device?
Real testing devices are the various models of mobile handsets that are used to run the website or app in order to test its functioning and behavioral patterns. These are actual handsets that the end user would use.
Generally, testing teams buy a couple of mobile handsets each with iOS, Blackberry, Android phones, tablets and iPads to test their software applications.
Here is an example of BrowserStack Live dashboard, running on Real Devices
Evolution of Testing Devices: From Real to Virtual Testing Devices
Although the results generated by testing on real devices are highly accurate, the cost of testing is on a higher side, as the company has to buy multiple devices and has to update them from time to time as new devices hit the market.
This expense of testing on real devices was a big challenge that companies have overcome by introducing virtual testing devices such as Simulators and Emulators. Thus, virtual testing devices came into regular use while conducting cross browser compatibility testing for the software.
What is a Virtual Testing Device?
A Virtual Testing Device is a software program on the computer, unlike a real device, that provides simulation for most of the important features of an actual smartphone device. It mimics the nature of the smartphone, which helps the testers to run the software application on it to get an idea about how it would run on the designated real device.
Although virtual testing devices happen to mimic the devices and are cost-efficient, it cannot replace real devices due to accuracy and reliability factors.
There are two types of virtual testing devices:
What are Emulators?
An emulator is a software that mimics the hardware and software of the target device on your computer. They do this by translating the ISA (Instruction Set Architecture) of the target device to the one used by the computer you are using to conduct testing using binary translation.
ISA is the set of instructions that are written in Machine Language by each of the processor families, which they use to build their own device configuration depicting the functionality and behavior of the device.
By translating the ISA of the target mobile device into your computer, you can mimic the way your target device works, forming a virtual environment for testing.
However, these near-native capabilities of the target mobile device, that enable you to adjust the physical sensors, geolocation, etc. come at the cost of latency.
What are Simulators?
A simulator is a software that helps your computer run certain programs built for a different Operating System. They are mostly meant for iPhone and iPad devices, unlike Android devices that can be emulated easily.
The iOS simulators mimic iOS and run the required application inside it, by sitting on top of the computer’s Operating System. But to run the iOS simulator, one needs to work on the macOS only, as it needs Apple’s native Cocoa API. This Cocoa API is essential for the GUI, runtime and many other operations.
This poses an issue as developers have to either work on the MacBook or virtualize macOS on their existing systems.
Simulators unlike emulators, do not mimic hardware. Thus one cannot investigate certain functionalities like battery usage, cellular interrupts, etc. while using simulators for testing.
Emulators vs Simulators: Know the difference
While these virtual testing devices are sometimes interchangeably used in communication, in reality, emulators and simulators differ from each other in many ways.
|Target Area||Mobile device hardware, software, and Operating System||Internal behavior of the mobile device|
|Provided by||Emulators are provided by device manufacturers||Simulators are provided by device manufacturers and other companies|
|Internal Structure||Written in Machine-level assembly language||Written in High-level language|
|Suitable for Debugging||Emulators are reliable and more suitable for debugging||Simulators, on the other hand, are less reliable and not so suitable for debugging|
|Performance||Binary translation makes them slower due to latency||Simulators are faster as there is no Binary Translation|
|Example||Android SDK||iOS Simulator|
Real testing device vs Virtual testing device
Real testing device and virtual testing devices differ in their capabilities.
|Criteria||Real testing device||Virtual testing device|
|Cost||Buying real devices at scale is cost prohibitive||Minimal cost incurred as oftentimes one can install them for free|
|Reliability||Real devices exhibit accurate results and allow for testing in the same condition as a user||Virtual testing devices only mimic the device and can’t replicate real user conditions like hardware and software configurations|
|Processing Speed||Software testing on real devices is much faster||Software testing on virtual devices is slower due to Binary translation|
|Suitable for Debugging||Debugging with real testing devices could be tricky, especially while capturing defects||Virtual devices make step by step debugging easy with the features, where you can capture the defects|
|Cross-Platform Testing||Cross-Platform Testing can be conducted normally using real devices||Cross-Platform Testing can be seamlessly conducted using virtual devices|
Real Device, Emulators and Simulators: When to test on what
With the features that each of these devices offer, when used diligently they can deliver optimized results making cross browser compatibility testing a lot easier. The best practices primarily include testing on the right devices for better outcomes.
Since the virtual devices offer a better debugging facility, it is best suited to use them during the initial stages of code development. With the frequent iterations that are required in the initial stages, using the virtual devices could make the cycle faster and more efficient.
On the other hand, Sanity Testing and User Acceptance Testing can be better done with real devices due to the accuracy factor. Parts of Regression testing could still be done using virtual devices after a point, it might result in compromised results.
Take a step ahead with Real Device Cloud
Real and virtual devices have their own pros and cons, that makes them suitable for one phase of testing and not so much for others. However, adopting a Real Device Cloud for testing can provide the best of both worlds.
Get your testing done right with just a single real device cloud that offers you
- Native real device experience, accuracy, and reliability
- Cost savings
- Easy debugging like virtual devices
- Web automation testing and app automation mobile testing for rapid testing at scale
- Hassle-free live interactive cross browser testing and interactive app testing
Real device cloud is thus the ideal solution, both for testers to find bugs and for developers to fix bugs with ease while keeping costs low.