Reducing battery consumption is an important goal, but it is sometimes important to keep some applications running in the background, even if it compromises the smartphone's lifetime. This is what a group of developers think that last year launched a website that intended to force Google to abandon the policy of "killing" applications. And this app inspired by that movement.
ADontKillMyApp is actually a benchmark application to understand the behavior of your smartphone with the applications that are in the background. The validation can take between one to eight hours, depending on the interval chosen by the user, and the application will launch several applications, calculating the tasks that have been performed.
If the percentage is low, it means that the smartphone is not allowing background applications to have access to resources. Even if the app helps to remove the protections that Android prevents or disable the "Twelve" mode of the operating system.
The app is available for Android on the Google Play store but is still in development mode, with early access. If you want you can check the source code that is available on Github.