Is there any penetration testing which detects any loop holes or security concern?
Hi , you can check this post , maybe will help you https://learn.techbeacon.com/units/how-get-started-mobile-penetration-testing-android
A fun side topic of testing you might want to look into is Mutation testing, this changes source code paths to see if the tests fail, i.e. sad paths have been tested in your code base. It’s not penetration testing, but it opens your thought process up to the inverse of what your code is capable of.
Also download the app, Show Java from play store and try hacking your app, see if you can extract the source code, and read what is written in it.
Then download MT Manager, it might help in hacking your own app. You can edit .dex files