Editor’s note: For further discussion on the topic of emulators, simulators, and physical devices, check out this in-depth article from the Sofy team!
While creating mobile applications, developers need to ensure that they look great and function as intended, all with as few defects as possible. By testing your app in a simulated environment that replicates real usage conditions, potential issues can be found and managed on the go.
However, as the diversity in mobile devices continues to increase, testing has a crucial role to play in the overall application lifecycle. But, given the huge swath of devices out there, running test cycles and debugging on every possible device can prove to be highly troublesome.
In this article, we will explore the pros and cons of using emulators and real devices for testing with the goal of helping developers solve for some classic testing dilemmas.
Testing using emulators
An emulator is an application (or software) that virtualizes all properties and behavior of a real device, including both the OS and hardware, onto a machine during the testing cycle. Emulators can be accessed through an internet browser or launched from a developer’s environment.
The main benefits that emulators provide are scalability and accessibility. With emulators, a tester can access an emulation environment, select a type of device and an operating system, and immediately command a running version of that device.
Essentially, emulators work like virtual machines. Developers usually utilize emulators as a next stage in the development and testing cycle after building and introducing new code, fabricated unit tests that can run during the Continuous Integration process.
Emulators provide significance advantages:
- Huge variety
Emulators provide developers a versatile method to test the most recent features, code patches, APIs, and many more across a variety of devices and screen resolutions, all without purchasing any actual devices for each configuration. Thus, testing applications on an emulator is (ideally) very close to testing on an actual gadget.
Smartphones and mobile devices can be very expensive, and prices for the latest in these devices only seem to continue to increase. This is where emulator can prove to be especially beneficial: Emulators present practically no maintenance costs. Additionally, with emulators, one squanders much less time and resources in having these devices repaired (or in replacing defective devices), whereas emulators may suffer from breakdowns only once in a while. And even if they do, fixing an emulator is comparatively quick and easy.
- Starting from the Baseline
Emulators can be utilized for both manual as well as automated testing. They are generally more valuable when an application is in the beginning phase of the software development lifecycle (SDLC). During the test, the tester can start from a freshly booted device state each time.
Practically-speaking, this can be very difficult to achieve with real devices, because they often requires manually-performed factory resets. Thus, testing on emulators can also increase the reliability of the test, as there won’t be any curveballs from a fresh virtual device during a test run.
However, for all their potential benefits, emulators also present users with unique disadvantages. Consider the following issues:
- False impressions
This is a very big one: One can never really depend on emulators because the conduct leading to the testing outcome may differ in a real-time situation. This can happen due to, for example, emulation software missing a couple of test conditions, or due to some hardware fallback on the tester’s machine that causes an emulator malfunction.
This implies that, sometime over the course of testing during the development lifecycle, developers will eventually have to cross verify if such a situation arises on a real device by retesting their product on one.
- Hardware and software mismatch
An emulator used by different vendors to test their applications on various hardware devices (from various manufacturers) can result in bugs. This is often due to hardware and software mismatch.
The underlying cause of such bugs is that an application’s creators tend to gain an extra edge in the market by providing more complex features that are never tested before on emulators and behave abruptly on different hardware. However, using hardware and software from the same vendor can reduce false positives and deliver more accurate results, as in that case the emulator will be well-adapted.
- Differences in computing resources
Emulators working on a host machine (or server) have a defined specification requirement with the machine’s computing power. However, the majority of the machines in any enterprise can’t sustain their proper function. This is due to their limited amount of computational power and memory. Hence, when you run emulators on your computer, your machine may struggle, and will not precisely mirror the user experience and device behavior during testing.
- Not all mobile apps can be tested on emulators
Emulators are only accessible for specific platforms. They don’t support the total array of applications from various vendors. They might also be incompatible with your application, or part of your application that includes important components.
For instance, a few emulators can test against Android devices from different manufacturers. However, they may or may not support other devices with different operating systems, like iOS. This implies that you may need to first introduce a large amount of fixes and adjustments before continuing to utilize the emulator.
Primary use case
The main use case for emulators is local development and validation. Emulators provide adaptable testing capabilities that you can use to set up complex modeling and testing different environments for the application. Emulators assist with mimicking numerous services for local development purposes.
With emulators, developers can even test an application against local storage services without incurring any extra costs. As emulators store data solely in memory (including pattern, schema, and configuration), all data resets on restart. Thus, emulators can theoretically be ideal for local development and testing, yet not for production deployments.
Testing using real devices
Generally, you should form a separate and customized testing plan for the app you develop. Sometimes a mobile application requires a specialized testing environment. This can be achieved by testing with actual, physical, real machines, devices utilized by users outside of the testing environment.
For real device testing, you must first acquire mobile devices of different models, operating systems, and screen sizes. Testing on these devices additionally permits developers to check for an application’s functionality and standards by way of real-time usage.
Real device testing presents a tremendous amount of benefits. Consider these points:
- Real-time testing
Everyday utilization of a phone incorporates a ton of interferences, such as receiving unexpected phone calls or your phone’s screen turning off. To truly take such real world conditions into account, your application should be tested for interferences like these, and this must be performed on a real device.
Real-time testing can help to easily simulate battery issues, handling interrupts, performance, notifications, OTPs and display jitters. These scenarios demonstrate that real device testing is generally more reliable than virtual device testing, as the former permits developers to test practically in all real-time situations.
- Better user interface validations
When trying to improve an application’s appearance, an emulator on a similar PC for each phone device will simply not work. Every device differs in factors like screen quality, size, and brightness. Hence, real device testing is necessary to take these aspects into account. Real device testing allows developers to ease up their user interface, for example, testing screen type (AMOLED, IPS, or LCD), shading of the screen, and the general look and feel of an application.
- Improved hardware and sensor-related validations
Real device testing permits developers to utilize sensors, such as a device’s gyroscope, accelerometer, orientation, and others. Sometimes, whether due to inefficient code or some other reason, an application may utilize excessive resources, like battery power, CPU, GPU, and RAM. Although the greater part of these things could potentially be caught on emulators, the battery drain is a major issue that is in practice difficult to catch on emulators, and hence real devices are again necessary.
The major disadvantage of utilizing real devices for testing purposes is the extremely high expenses generally associated with using them during the testing process. There are numerous device models available in the market, and testing on such a tremendous number of devices isn’t just time-consuming and tedious, it’s also very costly.
Enterprises must likewise consider financial aspects, not only in procuring these devices, but also their continued maintenance. Thus, real device testing can be overkill for some low-budget projects.
However, products like Sofy can provide a plethora of virtual devices during the testing cycle, on-demand. This helps in achieving maximum test coverage and simultaneously combats the additional cost overhead involved with real device testing.
Conclusion: There’s a better way!
When considering between an emulator or a real device for testing your application, it’s best to first identify which stage you are in the development life cycle. For instance, you may utilize an emulator to upgrade the look and feel of an application, then go on to perform different tests on real devices. You can choose whether to run application tests on an emulator or a real device dependent upon the situation, considering elements unique to your project, like budget, timelines, and other factors.
You can also use the combination of both, and establish your hybrid solution according to the application’s needs. Moreover, cloud-based testing platforms are currently emerging, and these can provide a highly accessible solution. Testing in the cloud means accessing numerous iOS, Android, and other operating system test emulators, as well as real devices, all directly from your browser.
Today, there’s no compelling reason to purchase real devices or to set up emulators. Instead, you can use cloud testing to test on many devices directly from your browser.