Test with Accessibility Scanner
Why?
Accessibility Scanner can reveal many accessibility problems the app might have for different user groups. It tests for four categories: content labeling, implementation, touch target size, and low contrast. While it does not reveal all possible accessibility problems, it can help with catching many low-hanging fruits.
Installation
First, install the Accessibility Scanner on your device. You can install it from Google Play.
Testing
Google has extensive support articles for using Accessibility Scanner:
Or, if you prefer watching a video, there's Accessibility scanner - Accessibility on Android by Android Developers, embedded below: