Testing the performance of your app on a real device allows you to validate its functionality as the end-user would experience it. Testing apps on real devices take into consideration tweaks to the operating system made by the manufacturer and the behaviour of other apps that you may not have considered in your staging or development environments. While many developers are using the Android Emulator to measure the performance of their app, the emulator only provides you with the performance of your app on an ideal device when running in a minimal environment.
For those who don’t know, an emulator is a virtual device (often a software program) that is designed to be a digital replica of the device in question. Since it duplicates the internal operation of the hardware, the OS, software, and support resources of the real device in question, you get an idea of how the app you are testing will run on the real device.
Regardless of how great an emulator is, there will come a point when you need to run a real device test for the app being designed. This is because certain questions will arise; how does the application look on the device’s display? Are there resolution problems on some devices? How does it interact with the device’s controls? How does it handle voice input and audio output? What is the actual speed of response? The reason why these questions arise is because of the differences in the performance metrics of emulators and real devices.
There are some metrics that cannot be measured by emulators. For example, let’s say you are using an emulator to test an application that utilizes the phone’s accelerometer; it is highly likely that the application might not work on the real device as expected. Emulators are also not able to simulate the incoming interrupts for SMS, as well as the incoming calls. There also might be a discrepancy in the performance of your application running on the same OS across different devices. This is something that emulators are not quite able to capture.
Emulators are useful for validating functional behaviours that are not specific to device or carrier. They also provide the ability to simulate situations that are difficult to recreate on a device. Let’s say you want to test the performance of an application on a device with a low battery. It can easily be imitated on the emulators. The capturing issue of screenshots over a simulator is very easy. Web app testing is also easy as users simply copy and paste the application on the URL. Overall, the performance of emulators tends to be slower than the original devices at times.
With real devices, the tester gets to physically switch from device to device in order to test the performance of the application. Testing with a device allows you to test your app with live networks. This type of testing is more difficult using only emulators: testing your app under different signal strength, latency, bandwidth, and packet loss across various types of wireless networks. However, testing your application on a network is key since most apps depend on the mobile network for operation and performance. Especially as real devices allow stringent performance testing issues like working with a real-time transport application for 15 hours continuously. This is something that cannot be successfully simulated by the emulators. Testing with real-world devices can also easily simulate incoming interruptions for SMS.
With real devices, the tester gets to physically switch from device to device in order to test the performance of the application. Testing with a device allows you to test your app with live networks. This type of testing is more difficult using only emulators: testing your app under different signal strength, latency, bandwidth, and packet loss of multiple devices connected to various types of wireless networks.
However, testing your application on a network is key since most apps depend on the mobile network for operation and performance. Especially as real devices allow stringent performance testing issues like working with a real-time transport application for 15 hours continuously. This is something that cannot be successfully simulated by the emulators. Testing with real-world devices can also easily simulate incoming interruptions for SMS.
The biggest drawback of using real devices is the cost. So you might want to use a few devices if you are simply testing the performance of the application. However, one major factor real devices fail to address is the load placed on applications at any given moment. That said, testing with real-world devices is very helpful in terms of interoperability testing as such testing provides more in terms of reliability. Overall real devices tend to perform faster than the emulators.
Considering the significant role of mobile applications in our day to day life, your applications will require a lot of testing to ensure that they perform optimally. That is why regardless of the differences in their performance metrics, testing in both the emulator as well as the real-world devices, will always be necessary. It is just a question of determining which testing mode works best in a given context.