With my experience in the mobile space over the past 2 decades, I rarely run across efficient mobile app testing that assures resource usage by the app as part of the overall test strategy and test plan.

Teams would often focus on the app usability, functionality, performance and security and as long as the app performs what it was designed to do — the app will get pushed to production as is.

Resource Consumption As an App Quality Priority

Let’s have a look at one of 2016 most popular mobile native apps, that is Pokemon Go. This mobile app alone, require constant GPS location services being active, it keeps the screen fully lit when in the foreground, operates the camera, plays sounds and renders 3d graphics content.

If we translate the above resource consumption when running this App on a fully charged Android device, research shows that in 2 hours and 40 minutes the phone will drop from 100% to 0% battery.

The thing is of course, that the end user will typically have at least 10 others apps running in the background at the same time, hence the battery drain of the device will be of course faster.

From a recent research done by AVAST, you can see 2 set of greediest apps in the market in Q3 2016. The 2 visuals below taken from the report show 2 sets of apps – 1 that is usually launched at the device startup, and the 2nd set of apps mostly launched by the users.

How to Test the App for Battery Drain?

• Mimic the end user environment
  
  Teams need to come as close as possible to their end-users, this is a clear requirement in today’s market. This means that from a battery drain testing perspective, the test environment needs to mimic the real user from the device perspective, OS, network conditions (2G, 3G, Wifi, Roaming), background popular apps installed and running on the device and of course a varying set of devices in the lab with different battery states.
• Test against multiple devices
  
  Device hardware is different across both models manufacturers. Each battery will obviously have a limited capacity than the other. Each device after a while will have degraded battery chemistry that impacts the performance, the duration it can last and more. This is why a variety of new, legacy and different battery capacities needs to be a consideration in any mobile device lab. This is a general requirement for mobile app quality, but in the context of battery testing – this gets a different angle that ought to be leveraged by the teams.
• Listen to the market and end-users’
  
  Since the market constantly changes, the “known state” and quality of your app including battery consumption and other resources consumption may change as well. This can happen due to app different performance on a new device that you have no experience with or it can be due to a new OS version released to the market by Google or Apple – we have seen plenty of examples like that, including the recent iOS 10.2 release.
  
  It is very hard to monitor these things in products, so one advice should be to start testing the app on OS Beta versions and measure the app battery consumption prior to the OS is released as GA – this can eliminate issues around new OS versions. Other methods that are commonly used by mobile teams is to monitor the app store and either get notified by the end-users’ about such issues (less preferred). Continuously including such tests on a refreshed device lab will reduce the risks and identify issues earlier in the cycle and prior to production. Make these tests or a subset of these part of your CI cycle to enhance test coverage and reduce risks.

Summary

In today’s market, there is not good automation method to test app battery drain, therefore my recommendation is to create a plethora of devices in the lab with varying conditions as mentioned above and measure the battery drain through native apps on the devices as well as timer measurements. The tests should be first against the app running on a clean device and then on a real end user device.